riddleme
Well-Known Member
This is my first thread in the Advanced section, I have spent most of my time here at RIU trying to lead new growers in the right direction. So I spend more time in the noob forum answering questions. But I do come here and read threads and find it very enlightning and enjoyable, a nice break from the constantly repeated questions elsewhere.
In preparation for my next grow (next set of experiments) I have been doing some research, a few things I am looking at is silica, and far infared light/heat, a very different way of topping as well as a few other things. In my travels to pursue this research I came across a new website that has info that blew me away (I'll share the link at the end) I am going to quote some of the info articles here so you can read em (but also in case the website fails) These articles emphasize the things that growers like myself and Uncle Ben have been spreading to the new growers here at RIU but also take that info in a very new direction. They are not MJ specific but as you read them you will see that it readily applies (as if they are talking about MJ without saying so)
This is going to be a lot of reading but in the end I think you all will agree that it is worth the time, here is the first article,,,,,,,,,,,
Nutrient Ratios for Modern Crops by Erik Biksa
Who has determined what the N-P-K values and ratios are that you feed your prized crop through the vegetative and bloom phases of growth? What about other important macro elements such as calcium and magnesium, and the complex relationships that trace elements such as boron, iron, zinc and manganese have with the other nutrient ions that influence the health and development of plants? There are 13 elements that are considered vital to plant growth, with many others showing to be beneficial. This gives a lot of possibilities in terms of the potential ratios and concentrations that these elements may have in a crop feeding nutrient solution; for example think, of the possible number of combinations you could have rolling 13 dice all at once.As indoor growers we are applying too much phosphorous because the recommendations for applications and formulations have been based on outdoor field agriculture practices.
So, now back to the question: “Who has determined the nutrient values and ratios in your crop feeding program?” All right, well most folks are likely to say “the manufacturer.” Okay, so the manufacturer determined the nutrient ratios. That beckons the question of how they were able to determine what concentrations and ratios of plant nutrient elements to provide for your particular crop and at what times in the vegetative and bloom phases of growth. Well from there you can only guess, unless you have information that says otherwise.
Chances are that the nutrient solution was formulated based on previous research that was performed on the nutrient requirements of various crops. Obviously, any reputable nutrient manufacturer will have also tested their formulation and will make adjustments, as required. There are hydroponic crop feeding solutions that were formulated in 1865, although Hoagland appears to have created the first “complete” nutrient solution in the 1930s. Since then, modern scientists and horticulturalists have learned much about plants and their nutrient requirements. One of the key points of knowledge is that different types of plants use nutrients in different quantities and ratios; creating preferred nutrient profiles for various types of plants. On top of that, the same type of plants will use nutrients differently when grown using different cultural practices or when grown in different climatic conditions. For example, outdoor field crops in natural settings that take six months to reach maturity versus indoor crops grown in artificial environments that will require only three months to reach maturity are hardly playing on the same ball field.
What does this all mean, and where is this article going with it? Well, to put it bluntly, there are a surprising number of nutrient formulations that are simply “wrong” for modern indoor growing, and here’s why:
So, why the improvement? There are several reasons, including plant genetics. However, a large part of this increase can be attributed to nutrient formulations and grow gear that have started to evolve to specifically address artificial and intensive modern growing environments and the types of plants that people like to grow in them. This article is here to state that there is still much more to be done in the way of research and improvements in nutrient formulations that are intended for intensive artificial growing environments and the new breed of plants being grown in them. Products that have been developed through research on modern indoor crops are now available to indoor growers, while some growers continue to use out-dated technologies to achieve moderate harvests.
Now that’s a bold statement. Well, here’s a little dose of proof:
Ask an experienced grower what the most important crop element is in the bloom phase, and the vast majority of the time you will hear phosphorous, which is the “P” in “N-P-K”. Yes, phosphorous is important, now asking the grower a follow-up question along the lines of “why is that the most important element?” Chances are you will hear, “because it’s used the most in the bloom phase.”
Wrong. Due to archaic field crop research crossed over into nutrient formulations intended for modern high producing indoor crops, there are some really huge misconceptions about what is optimal for nutrient ratios in the bloom phase for indoor crops grown in artificial environments. The simplest way to illustrate this fact is to look at one of the most popular types of products in the hydroponics industry, and that’s the “bloom booster.”
The majority of bloom boosters contain very high levels of phosphorous and moderate to lower amounts of potassium. They may also contain other macro and micro elements including magnesium, sulfur and iron. Growers begin to apply these types of products through the early bloom phase and late into flowering prior to “flushing” the crop before harvest. There seems to be a general consensus that the modern indoor containerized (or “systemized,” if you prefer) plant in the bloom phase needs abundant amounts of phosphorous relative to other nutrients. Well the truth is that they do not, because:
To answer the first part of the question, as indoor growers we are applying too much phosphorous because the recommendations for applications and formulations have been based on outdoor field agriculture practices, which simply don’t apply directly to indoor gardens. In nature the soil is very deep, and roots do not occupy the entire body of soil as they do in containers, beds or systems found with indoor gardens. Phosphorous leeches from the root zone in natural soils quickly, washing away from the contact zone with plant roots, as it drains with water further into the depths of the earth. To ensure a healthy supply of phosphorous, outdoor conventional field agricultural growers do a sort of “over-application” of phosphorous, because it has been determined that much of it will be quickly leeched away from the plant roots; what remains at any given time can be taken up by the crop. From this, we can learn that excessive “P” values in our N-P-Ks are not necessary for indoor growers, where phosphorous maintains a high level of contact within the root zone of plants grown in artificial soils and in containers, beds and systems commonly found with intensive indoor growing environments.
Now what affects can excessive phosphorous levels have on crops? Firstly, excessive levels of phosphorous can create nutrient imbalances in the root zone, and consequently inside the plant. This creates a form of stress in the plant which can diminish yield potential and increase the plant’s susceptibility to problems such as insects and diseases. Conversely, it can also be said that a slight stress induction from excess phosphorous may have some benefits in the late bloom/ripening phase as the plants reach maturity. However, creating this stress from early in the bloom phase and continuing it throughout will not create the correct nutrient profile for optimal harvest potential. This is not to say that growers should not supply phosphorous throughout the bloom phase, although it is to say that grower’s crops will yield larger harvests if phosphorus is supplied in the correct and balanced ratios with other nutrients, as determined through careful tissue analysis of indoor crops versus conventional field agricultural data.
In simple terms, based on the macro and micro nutrient profile analysis of a healthy, high yielding indoor crop (plant tissue analysis) growers have some options with how best to address the nutritional requirements of their favorite crop to get bigger yields than they have ever been able to achieve before.
Firstly, don’t apply bloom boosters with high phosphorous to potassium ratios continually through the bloom phase. For the first week of flowering to help trigger the natural plant stresses that amplify the plant’s flowering process, it’s okay to give the crop a dose of bloom boosters that have higher P to K ratios in the NPK values stated on the label. Usually, these types of bloom boosters that are formulated for indoor crops at the onset of flowering will also have other components in the formulation that help to control vertical growth; stacking internodes and flowering sites tighter together for each foot of vertical growth to give maximum yields.
After the first week of flowering where a “trigger” bloom booster maybe used to help ignite the bloom phase, you may begin to apply a balanced P:K bloom booster in conjunction with a balanced base nutrient program. If you have gleamed anything from this article, you will be wondering what the appropriate P:K ratio would be for indoor flowering crops, and current research has been demonstrating that a 1:2 ratio seems to work best, the polar opposite of some of the bloom boosters currently being used by indoor growers. To build the biggest and heaviest flowers and fruits, bloom boosters should supply more than just the correct P:K ratios. Additions of L-amino acids and other forms of reduced nitrogen will further amplify and enhance the plant’s natural reproductive response, leading to bigger and heavier harvests of higher quality. Magnesium and sulfur are also very important components in the bloom process of most indoor crops.
In the late flowering phase, when the plant is ripening, and in some instances producing elevated levels of essential oils, a slight “spike” in phosphorous levels will induce a level of stress that can help to enhance crop quality. For example, this is when a 2:1 P:K ratio may be appropriate. Note that at this time, the plant is not developing structurally anymore. All crops should be sufficiently flushed of excess nutrients, beginning at least one week before the anticipated date of harvest. This is accomplished by applying a leeching agent to the growing medium or system and then running straight water possibly with digestive enzymes and/or humates for the final days before harvest.
Three part base nutrient systems have been widely used and accepted through the indoor gardening community, and have been delivering great results for years. Based on modern research conducted on indoor grown high yielding crops, it was determined that using the three part nutrient system actually produced better results when being applied in a 1:1:1 ratio versus the common 3:2:1 ratio, especially when bloom boosters intended for indoor crops were used in conjunction with the three part nutrient system. 2:1 ratios of three part base nutrients were the least effective of all (where the “grow” component was omitted entirely through the bloom phase).
Upon analyzing the nutrient levels and ratios achieved in the nutrient solution for feeding indoor crops in the bloom phase, applying the base nutrients in a 1:1:1 ratio using popular three part nutrient components, the level and ratios much more closely resembled those of the internal nutrient levels and ratios of the plant being grown versus using the three part nutrient components in the common 3:2:1 method.
After all is said and done, there is only really one way to find out what is going to give you the biggest and best quality harvests, and that’s to experiment a little. If anything, it’s the hope of this article that you will begin to question where the nutrient values you are using having been derived from, and if they are in fact correct for your modern indoor crop. You just may find that by tinkering with the products you are already using or better yet, by adopting more modern formulations, that you are able to surpass even your largest yield expectations. So, if in the last decade we have been able to nearly double yields through research and experimentation on indoor crops, just imagine the types of harvest we may have in another 10 years. This advancement cannot continue, however, without growers who are willing to push the limits and boundaries of what is held as the “common truth” of the times, because more often than not, it won’t remain “the truth” forever.
Here is the second article,,,,,,,,,,,,,,,,,
Yield of Dreams: An Optimal External Environment for Accelerated Crop Growth by Erik Biksa
Understanding what exactly makes your favorite plants tick will give you the insight you need to supercharge the natural process for faster growth and bigger yields.
Nature has created the perfect internal and inherent growing system within plants. Some growers using advanced crop feeding programs may already be accelerating plant growth, while not fully understanding the process that is working to their benefit. It is the intention of this article to shine some light on how the photosynthetic process(es) work and how they relate to modern indoor growing, practices that include artificial lighting, elevated carbon dioxide levels and intensive crop feedings.
Plants are considered to be “autotrophic,” basically meaning that they create their own food. They do this through photosynthesis, which translated means “to put together with light.” There are three foundations to photosynthesis:
1. Photosynthetic activity – the capturing of light energy to combine carbon dioxide (in air) and water (in soil) to produce glucose; the chemical energy that is used to fuel all the necessary internal reactions for plants to grow. In simple terms, in the presence of light plants’ manufacture the carbohydrates they need to do “work.” Oxygen is a by-product of this process.
2. Respiration – this mostly occurs in the “dark” phase. Plants “burn” the carbohydrates they create during light reactions in the presence of oxygen to send the energy through the plant’s internal “wiring,” which is a network of proteins/amino acids to supply a variety of functions with the free energy they require. Carbon dioxide is a by-product of this process, making it a “mirror” reaction to the photosynthetic reaction, as above.
3.Transpiration – occurs at higher rates during the light reactions/photosynthetic activity. This relates to the loss of water vapor through the leaves, as water is transported from the growing medium with nutrients, through the roots. The nutrients are delivered into the plants, while a portion of the hydrogen and oxygen ions (from H2O) are assimilated through the plant. The majority of the water taken up escapes the plant through the leaves. Water pressure (turgor) inside the plant is what gives plants their rigidity and structure; as plants are after all, “bone-less.”
Light Energy = Growth: Healthy plants with ample CO2, water and nutrients will continue to photosynthesize under bright light conditions.
One of the most important things to understand about how these processes work on an individual basis, and as they do in harmony with one another, is that they need to be maintained in a balanced equation.
For example, the chemical equation in photosynthesis can be given as:
So if one of the pre-cursors in the reaction is lacking, for example, the plant has only three units of carbon dioxide relative to six units of water in the presence of bright light (radiant energy), the reaction can only work as high as a rate that three units of carbon dioxide will allow, with the remainder of the light and water being “wasted.” In fact, it may create a situation that is more than just inputs being “wasted,” it can actually create situations where the plant is running at a deficit.
In other types of situations, common to indoor gardening, when temperatures climb above 85°F, the rate at which respiration occurs (the burning of carbohydrates for energy) can exceed the rate of photosynthesis (creating carbohydrates). This creates a situation where by some definition, the plant is “working itself to death.”
Very bright light conditions are easy for indoor gardeners to supply using HID (high intensity discharge) lighting sources. This is usually the factor that creates an “imbalance” in the equation and relationship between the photosynthetic process, respiration and transpiration. The plant is saturated with intense light energy, while other factors such as carbon dioxide, temperatures, minerals and vitamins required by photosynthesis, etc. are not available in the same abundance. This imbalance puts the plant in a situation similar to excessive temperatures where the plant is working itself to death.
Bear in mind that modern indoor growers are putting incredible demands on the super-strains of plants that are cultivating. In nature similar types of crops may require four to six plus months to reach maturity in natural settings. Indoors, growers are driving the same types of plants to reach complete maturity in two to four months. That equates to twice the work that is required by the plant on a day-to-day basis! The demands placed on the plants by the environment supplied by the indoor grower are astounding when you consider the time frame it takes the crop to reach maturity versus in natural settings.
"Nature has created the perfect internal and inherent growing system (photosynthesis) within plants."
So how exactly are we accomplishing this incredible feat as growers? Well, those of us who accomplish it the most successfully are driving and fuelling this natural process through improved crop growth technologies. As growers, we are supplying an abundance of the factors necessary and in the correct balance to amplify the plant’s natural and inherent responses.
In today’s day and age, it’s easy to provide optimal light durations (day lengths) and incredible lighting intensities using readily available artificial lighting sources. HPS (high pressure sodium) lamps do a good job of producing lots of lumens, although they are not as rich and complete as the sun in spectrum. They also produce a lot of heat, which can be detrimental to plant growth, as we discussed earlier.
Air- and water-cooled lighting fixtures can drastically reduce the excess unwanted heat created, removing it at the source, rather than overheating the plants. Artificial lighting spectrums can be improved by using modern HID lamps that have their spectrums enhanced to stimulate plant growth rather than illuminate parking lots. While they are no match for the sun’s “solar nutrition,” they are an improvement.
High output T5 fluorescent lights can be very rich in spectrum, and are ideal for stimulating healthy plant growth in the earlier stages, and can in some instances be used to raise plants to maturity.
Heavy Loads: When plants are able to manufacture adequate supplies of chemical energy, heavy fruit loads may develop.
LEDs perhaps offer growers the best opportunity to provide very exacting light wavelengths for different growth phases. At present, it would appear that the technology itself is “smarter” than we are; growers and LED manufacturers alike are learning about what will work best at different growth phases, as LED fixtures can be tailored to provide very exact wavelengths of light. The technology goes far beyond the capabilities of what HID lighting can offer. LED diodes emit very negligible amounts of heat, reducing cooling requirements and costs. The fact that they run cooler allows for more efficient supplementation of carbon dioxide levels in the growing environment for faster growth rates and bigger yields, due to reduced air exchange requirements.
Carbon dioxide (CO2) for light reactions is usually the most limiting factor in indoor gardens, assuming cooling requirements have been accomplished with a high level of control. If growers are able to maintain optimal temperatures during the intense light cycle, plants will grow at noticeably increased rates when elevating the levels of carbon dioxide in the growing environment. Carbon is the biggest component in the dry weight of plants, and elevating carbon dioxide levels can have a direct effect on increasing dry plant weights at maturity. Fermentation, releases of bottled CO2, and generation of CO2 through gas-fired combustion are common methods growers may use to elevate CO2 levels in the growing environment for better results.
All of the areas discussed above are “exogenous” or external factors that can be controlled by the grower through the use of specialized mechanical equipment. Now what about the internal or “endogenous” reactions that are going on inside of the plant? This is where the real magic happens.
Modern, advanced nutrient manufacturers have dissected the internal responses and materials required to fuel and sustain high rates of growth for intense indoor growing environments. These “ingredients” have been discovered, refined and blended into exacting ratios to create crop feeding programs that help meet and stimulate the tremendous functional demands placed on crops by modern indoor growers.
The end result of the photosynthetic response is glucose, which is “burned” during respiration to release energy. There are crop feeding supplements that are able to supply relatively available sources of carbohydrates to plants when they are applied accordingly. This means that for example, in instances when the rate of respiration is exceeding the rate at which photosynthesis (during high light and warm conditions in the presence of CO2), the plant’s reserves of energy may not run at a deficit, allowing the plant to continue growth, rather than “shutting down” to prevent exhaustion or even plant death.
Consider high intensity activity in humans such as long distance running. Athletes load up on carbohydrates to provide their bodies with the necessary levels of energy to meet the high demands of the task they are placing on their body’s energy system. During the activity, runners breathe harder, requiring more oxygen. Plant growth has a similar demand for vital gas, although it is carbon dioxide rather than oxygen. If there is insufficient carbohydrates or necessary vitamins, minerals, gases, etc., the runner will finish poorly, or may not even finish at all in some instances. This is the case with plants.
After strenuous physical demands plants, like athletes, also require proteins to repair and build new tissue and energy transfer ways to supply and direct energy. This is where L-amino acids for crops come into play. Plants normally have to manufacture amino acids and other forms of reduced nitrogen to help build new tissue and create the energy transfer ways.
Growers who supply crop feeding supplements that contain broad spectrum of L-amino acids including lysine during times of great mass gains, for example in the peak bloom phase, are in fact providing crops with the necessary materials to get bigger faster. The plant will not have to work as hard to manufacture these proteins, as they are supplied at some level of availability. Note that microbes in beneficial bacteria and fungi help to improve this process. This would be similar to an athlete drinking a well formulated protein supplement after strenuous physical activity versus eating a steak. The athlete’s body will more readily assimilate select proteins in their ideal ratios, rather than expending energy to convert proteins supplied in cruder forms such as meats, to forms that the body can use to build and repair tissue. This quickly translates into greater mass gains in shorter time frames; something every indoor grower should aim to accomplish.
Vitamins, minerals, enzymes and other co-factors also play a strong role at which the rate of all the reactions required by the plant to grow may occur. Most minerals are supplied to the plant through the roots, carried up with water in the transpiration process (loss of water through leaves). Without these vital minerals, and in their correct ratios for the type of crop being grown, the rate at which photosynthesis may occur will decrease. This is why it is important to choose your crop nutrients carefully. The correct balance and a high level of availability under a wide range of growing conditions should be of careful consideration.
Plants typically manufacture their own vitamins, enzymes and co-factors, although in nature it has been demonstrated that these substances may also occur in the growth medium and be transferred to the plant for uptake and assimilation for functions. Again, this is typically assisted through beneficial microbes, which are available in modern formulations to inoculate indoor crops. These beneficial vitamins, enzymes and co-factors can also be supplied through specialized and well formulated crop feeding additives more or less directly to the plants.
Similar in concept to supplementing the crop with carbohydrates and amino acids for higher rates of growth and mass gain, additions of vitamins, enzymes and co-factors will benefit the crop. By using specialized crop feeding programs designed to promote bigger yields and healthier plants grown under intense artificial light and elevated carbon dioxide levels, the grower is helping to “balance” the plant’s internal equation that is dictated by the three key foundations to plant growth: photosynthetic activity, respiration and transpiration.
Now that you know more about what exactly is making your favorite plants tick, you may be able to improve your yields, growth rates and crop quality by respecting and maintaining an understanding of these very important principles. Keep them in mind when constructing the ideal environment for your plant with regards to light intensity and quality, temperature and CO2 levels.
Once you can maintain and manage the optimal external environment, your crop can take advantage of full spectrum feeding programs that have been designed specifically to satisfy the needs of your plants being grown in an accelerated environment. In fact, some crop supplements will help your plants to maintain a higher degree of health and growth rates, even in less than perfect environments. However, supplements are not a replacement to creating the optimal growing environment for your favorite type of plants. It is about harmony, balance and respecting the perfect inherent mechanisms for growth that nature has developed, and with understanding we may achieve our own personal yield of dreams.
And one more,,,,,,,,,,,,,,,,,,,,
pH Management for Optimal Results by Andrew Taylor
Optimum pH for nutrient solutions
For nutrients to remain dissolved and, therefore, available for uptake by roots, it is critical to maintain the pH between 5.0 and 6.0 with an absolute maximum of 6.5. When the pH of the nutrient solution is above 7.0, calcium, sulfate (and trace elements of copper, iron, manganese and zinc) can precipitate and become unavailable to the roots, causing plumbing blockages. High pH values, or those above 6.0, are to be avoided more than low values of 4.5 to 5.0. The effect of low pH upon the stability of nutrients is relatively insignificant.
The precise pH at which precipitation of macro-nutrients starts is determined by the combined concentrations of calcium and sulfate. Except for fertilizers low in calcium and sulfate this problem commonly occurs at pH 6.5 where the net* EC is 2.5 mS, or pH 7.0 for 1.5 mS solutions. Hence, to avoid precipitation, higher nutrient concentrations generally must be held at lower pH values. *Assume make-up water has nil EC.
In spite of this precipitation problem, some references advocate pH values well above 6.5 for some plant varieties, conditions that risk depleted concentrations of the above mentioned elements.
Figure one: Simplified illustration of how nutrient uptake effects pH of the nutrient solution
pH recommendation of 6.2 to 6.3?
Although 6.2 to 6.3 is a popular pH recommendation, which has no scientific basis. It appears to have gained mythological status from the early days of hydroponics when the only cheap means of measuring pH was the common ‘bromothymol blue’ pH indicator used for testing fish tank water. Interestingly, the lowest pH value able to be determined by that indicator is about 6.2. Hence, this value has unfortunately become an entrenched recommendation in some sections of the hydroponic industry.
Adjusting nutrient pH
The working nutrient pH should be checked at the following times:
Figure two: pH indicators are useful for determining how much acid needs to be added to the nutrient reservoir.
How to minimize pH fluctuation
Step 1. Measure the pH: Use either a liquid pH indicator or an electronic pH meter (see sections below). Before measuring the pH, ensure that the nutrient is well stirred and that the sampling container is clean.
Step 2. Choosing a target pH: Note that it is inconvenient and unnecessary to hold pH at a single point value. Therefore, choose a target pH that minimizes the amount of pH maintenance:
Step 3. Adjusting the pH: Add a small amount of pH down or up product*. Then stir well and check pH. Repeat this process until the target pH is achieved.
*Important: Pre-dilute the dose into one quart (or at least 100 fold) of water before adding to nutrient, then rapidly stir the nutrient as you add this mixture. Failure to do this may cause permanent precipitation of essential nutrients. Also, if accidental overdosing to above 6.5 occurs, reduce the pH back to below 6.0 as quickly as possible using pH down.
Figure three: This is the color range produced by a wide range pH indicator within the optimum pH range 5.0 to 6.5. Note the ease with which pH change can be detected.
Handy hints for adjusting nutrient pH
1. Add “high pH” (alkaline) additives before adding nutrient: Most additives will affect nutrient pH at least slightly. The best technique to adopt with those that elevate pH significantly is to add them to the water and adjust the pH down to 6.0 prior to adding the nutrient.
The less preferred but simplest alternative is to pre-dilute the additive in a separate volume of raw water. Then once this solution is added to the nutrient solution, quickly lower the pH to below 6.5. Note that a white cloudy precipitate (calcium sulfate) may form when the pre diluted additive initially merges with the nutrient solution. However, because the initial particle size of the precipitate is small, it will usually re-dissolve if the pH is immediately re-adjusted.
2. Do not pre-adjust pH of raw water: Note that the pH values being discussed here are the values of the working nutrient solution, not your make-up water. Unless your make-up water has a high alkalinity, do not bother attempting to adjust its pH prior to the nutrient being added. If you attempt this procedure you will typically get wild pH swings either side of the pH target without ever landing on the target value.
3. Estimating the volume of acid (especially for larger systems):
pH indicators are undoubtedly the simplest and most reliable method of measuring nutrient pH. Although they will not distinguish between, for example, a pH of 5.2 and 5.3, wide range indicators with good color resolution can be:
pH indicators work on the principle that the color produced by the particular dye used in the indicator formulation is dependant on the pH of the solution (figure three).
Experience shows if you are aiming to adjust pH to 5.5 (orange) then an accuracy of +/- 0.2 is achievable. Because of their fundamental accuracy, reliability and easy of use, wide range pH indicators are the preferred method for measurement of pH in nutrient solutions. Note that pool and aquarium pH indicators are usually not suitable because unlike broad range indicators, they do not operate below pH 6.0.
Figure four: Thoroughly stir nutrient reservoir before sampling. Then leave the electrode in the sample for a few minutes before switching the meter on and taking the measurement. Do not immerse the electrode deeper than ~1 inch.
Taking pH readings
Step 1. Before measuring the pH ensure that the nutrient is well stirred, especially after pH up or down products are used. This is one of the most common mistakes made when testing pH (or conductivity). Also, ensure that the sampling container is clean.
Step 2. Using the sampling vial, remove a small sample of nutrient from the nutrient reservoir, add a drop of the indicator, mix, and then compare the final solution color with those on the colored reference chart (figure three).
Step 3. If the pH is not between 5.0 and 6.5, adjust it immediately.
Measuring pH with pH meters
pH meters employing a glass electrode are useful for precise pH measurement in nutrient solutions but require frequent calibration, proper storage and handling to ensure accuracy and reliability. The principle on which such meters operate is based on the fact that when glass of a certain composition separates two aqueous solutions having different hydrogen ion concentrations, a voltage is developed between the two faces of the glass. The electronic meter is simply a very sensitive voltmeter which measures that voltage but is calibrated in terms of pH units instead of volts.
Obtaining pH readings
Step 1. Make sure the meter is calibrated.
Step 2. Remove a ‘representative’ sample from the nutrient reservoir (figure four):
Step 4. If the pH is not between 5.0 and 6.5, adjust it immediately.
Step 5. When complete, rinse the electrode with distilled water. Store the electrode in a proper storage solution when not in use.
The website is the same as the title of this thread, Maximumyield.com. There are lots of good articles there and it is like an online magazine or Ezine, they have hundreds of great articles as well as several charts (click extras link), I hope everyone enjoys them as much as I did
Riddle Out
In preparation for my next grow (next set of experiments) I have been doing some research, a few things I am looking at is silica, and far infared light/heat, a very different way of topping as well as a few other things. In my travels to pursue this research I came across a new website that has info that blew me away (I'll share the link at the end) I am going to quote some of the info articles here so you can read em (but also in case the website fails) These articles emphasize the things that growers like myself and Uncle Ben have been spreading to the new growers here at RIU but also take that info in a very new direction. They are not MJ specific but as you read them you will see that it readily applies (as if they are talking about MJ without saying so)
This is going to be a lot of reading but in the end I think you all will agree that it is worth the time, here is the first article,,,,,,,,,,,
Nutrient Ratios for Modern Crops by Erik Biksa
Who has determined what the N-P-K values and ratios are that you feed your prized crop through the vegetative and bloom phases of growth? What about other important macro elements such as calcium and magnesium, and the complex relationships that trace elements such as boron, iron, zinc and manganese have with the other nutrient ions that influence the health and development of plants? There are 13 elements that are considered vital to plant growth, with many others showing to be beneficial. This gives a lot of possibilities in terms of the potential ratios and concentrations that these elements may have in a crop feeding nutrient solution; for example think, of the possible number of combinations you could have rolling 13 dice all at once.As indoor growers we are applying too much phosphorous because the recommendations for applications and formulations have been based on outdoor field agriculture practices.
So, now back to the question: “Who has determined the nutrient values and ratios in your crop feeding program?” All right, well most folks are likely to say “the manufacturer.” Okay, so the manufacturer determined the nutrient ratios. That beckons the question of how they were able to determine what concentrations and ratios of plant nutrient elements to provide for your particular crop and at what times in the vegetative and bloom phases of growth. Well from there you can only guess, unless you have information that says otherwise.
Chances are that the nutrient solution was formulated based on previous research that was performed on the nutrient requirements of various crops. Obviously, any reputable nutrient manufacturer will have also tested their formulation and will make adjustments, as required. There are hydroponic crop feeding solutions that were formulated in 1865, although Hoagland appears to have created the first “complete” nutrient solution in the 1930s. Since then, modern scientists and horticulturalists have learned much about plants and their nutrient requirements. One of the key points of knowledge is that different types of plants use nutrients in different quantities and ratios; creating preferred nutrient profiles for various types of plants. On top of that, the same type of plants will use nutrients differently when grown using different cultural practices or when grown in different climatic conditions. For example, outdoor field crops in natural settings that take six months to reach maturity versus indoor crops grown in artificial environments that will require only three months to reach maturity are hardly playing on the same ball field.
What does this all mean, and where is this article going with it? Well, to put it bluntly, there are a surprising number of nutrient formulations that are simply “wrong” for modern indoor growing, and here’s why:
- The formulation(s) has been based on un-applicable or less relevant research information. The data gathered growing field crops using conventional methods tells us something, however, it cannot be accurately used to create optimal nutrient ratios for the unique requirements of modern crops grown indoors.
- For optimal results, crop formulas need to be created specifically for the type of crop being grown and the types of conditions it is being grown under; what’s optimal for one type of plant will not be optimal for another. One size does not fit all. However, nutrient components may be tailored by savvy growers to create the optimal profile for their particular plant type; provided that the grower knows what those ratios are.
- The optimal nutrient ratios change slightly through different crop developmental phases such as in the seedling/cutting phase versus the vegetative growth phase versus the bloom phase. It’s important to know what these changes are and to have them reflected in the crop feeding schedule.
So, why the improvement? There are several reasons, including plant genetics. However, a large part of this increase can be attributed to nutrient formulations and grow gear that have started to evolve to specifically address artificial and intensive modern growing environments and the types of plants that people like to grow in them. This article is here to state that there is still much more to be done in the way of research and improvements in nutrient formulations that are intended for intensive artificial growing environments and the new breed of plants being grown in them. Products that have been developed through research on modern indoor crops are now available to indoor growers, while some growers continue to use out-dated technologies to achieve moderate harvests.
Now that’s a bold statement. Well, here’s a little dose of proof:
Ask an experienced grower what the most important crop element is in the bloom phase, and the vast majority of the time you will hear phosphorous, which is the “P” in “N-P-K”. Yes, phosphorous is important, now asking the grower a follow-up question along the lines of “why is that the most important element?” Chances are you will hear, “because it’s used the most in the bloom phase.”
Wrong. Due to archaic field crop research crossed over into nutrient formulations intended for modern high producing indoor crops, there are some really huge misconceptions about what is optimal for nutrient ratios in the bloom phase for indoor crops grown in artificial environments. The simplest way to illustrate this fact is to look at one of the most popular types of products in the hydroponics industry, and that’s the “bloom booster.”
The majority of bloom boosters contain very high levels of phosphorous and moderate to lower amounts of potassium. They may also contain other macro and micro elements including magnesium, sulfur and iron. Growers begin to apply these types of products through the early bloom phase and late into flowering prior to “flushing” the crop before harvest. There seems to be a general consensus that the modern indoor containerized (or “systemized,” if you prefer) plant in the bloom phase needs abundant amounts of phosphorous relative to other nutrients. Well the truth is that they do not, because:
- Phosphorous is highly available to containerized or systemized plants grown indoors relative to outdoor conditions where it is quickly leeched away from the root zone via mass flow.
- When examining analytical reports charting the nutrient profile of a high yielding indoor crop at harvest (plant tissue analysis) it becomes clear that even in a variety of strains within the same plant type, that the plant requires nearly five times more each nitrogen and potassium relative to phosphorous.
To answer the first part of the question, as indoor growers we are applying too much phosphorous because the recommendations for applications and formulations have been based on outdoor field agriculture practices, which simply don’t apply directly to indoor gardens. In nature the soil is very deep, and roots do not occupy the entire body of soil as they do in containers, beds or systems found with indoor gardens. Phosphorous leeches from the root zone in natural soils quickly, washing away from the contact zone with plant roots, as it drains with water further into the depths of the earth. To ensure a healthy supply of phosphorous, outdoor conventional field agricultural growers do a sort of “over-application” of phosphorous, because it has been determined that much of it will be quickly leeched away from the plant roots; what remains at any given time can be taken up by the crop. From this, we can learn that excessive “P” values in our N-P-Ks are not necessary for indoor growers, where phosphorous maintains a high level of contact within the root zone of plants grown in artificial soils and in containers, beds and systems commonly found with intensive indoor growing environments.
Now what affects can excessive phosphorous levels have on crops? Firstly, excessive levels of phosphorous can create nutrient imbalances in the root zone, and consequently inside the plant. This creates a form of stress in the plant which can diminish yield potential and increase the plant’s susceptibility to problems such as insects and diseases. Conversely, it can also be said that a slight stress induction from excess phosphorous may have some benefits in the late bloom/ripening phase as the plants reach maturity. However, creating this stress from early in the bloom phase and continuing it throughout will not create the correct nutrient profile for optimal harvest potential. This is not to say that growers should not supply phosphorous throughout the bloom phase, although it is to say that grower’s crops will yield larger harvests if phosphorus is supplied in the correct and balanced ratios with other nutrients, as determined through careful tissue analysis of indoor crops versus conventional field agricultural data.
In simple terms, based on the macro and micro nutrient profile analysis of a healthy, high yielding indoor crop (plant tissue analysis) growers have some options with how best to address the nutritional requirements of their favorite crop to get bigger yields than they have ever been able to achieve before.
Firstly, don’t apply bloom boosters with high phosphorous to potassium ratios continually through the bloom phase. For the first week of flowering to help trigger the natural plant stresses that amplify the plant’s flowering process, it’s okay to give the crop a dose of bloom boosters that have higher P to K ratios in the NPK values stated on the label. Usually, these types of bloom boosters that are formulated for indoor crops at the onset of flowering will also have other components in the formulation that help to control vertical growth; stacking internodes and flowering sites tighter together for each foot of vertical growth to give maximum yields.
After the first week of flowering where a “trigger” bloom booster maybe used to help ignite the bloom phase, you may begin to apply a balanced P:K bloom booster in conjunction with a balanced base nutrient program. If you have gleamed anything from this article, you will be wondering what the appropriate P:K ratio would be for indoor flowering crops, and current research has been demonstrating that a 1:2 ratio seems to work best, the polar opposite of some of the bloom boosters currently being used by indoor growers. To build the biggest and heaviest flowers and fruits, bloom boosters should supply more than just the correct P:K ratios. Additions of L-amino acids and other forms of reduced nitrogen will further amplify and enhance the plant’s natural reproductive response, leading to bigger and heavier harvests of higher quality. Magnesium and sulfur are also very important components in the bloom process of most indoor crops.
In the late flowering phase, when the plant is ripening, and in some instances producing elevated levels of essential oils, a slight “spike” in phosphorous levels will induce a level of stress that can help to enhance crop quality. For example, this is when a 2:1 P:K ratio may be appropriate. Note that at this time, the plant is not developing structurally anymore. All crops should be sufficiently flushed of excess nutrients, beginning at least one week before the anticipated date of harvest. This is accomplished by applying a leeching agent to the growing medium or system and then running straight water possibly with digestive enzymes and/or humates for the final days before harvest.
Three part base nutrient systems have been widely used and accepted through the indoor gardening community, and have been delivering great results for years. Based on modern research conducted on indoor grown high yielding crops, it was determined that using the three part nutrient system actually produced better results when being applied in a 1:1:1 ratio versus the common 3:2:1 ratio, especially when bloom boosters intended for indoor crops were used in conjunction with the three part nutrient system. 2:1 ratios of three part base nutrients were the least effective of all (where the “grow” component was omitted entirely through the bloom phase).
Upon analyzing the nutrient levels and ratios achieved in the nutrient solution for feeding indoor crops in the bloom phase, applying the base nutrients in a 1:1:1 ratio using popular three part nutrient components, the level and ratios much more closely resembled those of the internal nutrient levels and ratios of the plant being grown versus using the three part nutrient components in the common 3:2:1 method.
After all is said and done, there is only really one way to find out what is going to give you the biggest and best quality harvests, and that’s to experiment a little. If anything, it’s the hope of this article that you will begin to question where the nutrient values you are using having been derived from, and if they are in fact correct for your modern indoor crop. You just may find that by tinkering with the products you are already using or better yet, by adopting more modern formulations, that you are able to surpass even your largest yield expectations. So, if in the last decade we have been able to nearly double yields through research and experimentation on indoor crops, just imagine the types of harvest we may have in another 10 years. This advancement cannot continue, however, without growers who are willing to push the limits and boundaries of what is held as the “common truth” of the times, because more often than not, it won’t remain “the truth” forever.
Here is the second article,,,,,,,,,,,,,,,,,
Yield of Dreams: An Optimal External Environment for Accelerated Crop Growth by Erik Biksa
Understanding what exactly makes your favorite plants tick will give you the insight you need to supercharge the natural process for faster growth and bigger yields.
Nature has created the perfect internal and inherent growing system within plants. Some growers using advanced crop feeding programs may already be accelerating plant growth, while not fully understanding the process that is working to their benefit. It is the intention of this article to shine some light on how the photosynthetic process(es) work and how they relate to modern indoor growing, practices that include artificial lighting, elevated carbon dioxide levels and intensive crop feedings.
Plants are considered to be “autotrophic,” basically meaning that they create their own food. They do this through photosynthesis, which translated means “to put together with light.” There are three foundations to photosynthesis:
1. Photosynthetic activity – the capturing of light energy to combine carbon dioxide (in air) and water (in soil) to produce glucose; the chemical energy that is used to fuel all the necessary internal reactions for plants to grow. In simple terms, in the presence of light plants’ manufacture the carbohydrates they need to do “work.” Oxygen is a by-product of this process.
2. Respiration – this mostly occurs in the “dark” phase. Plants “burn” the carbohydrates they create during light reactions in the presence of oxygen to send the energy through the plant’s internal “wiring,” which is a network of proteins/amino acids to supply a variety of functions with the free energy they require. Carbon dioxide is a by-product of this process, making it a “mirror” reaction to the photosynthetic reaction, as above.
3.Transpiration – occurs at higher rates during the light reactions/photosynthetic activity. This relates to the loss of water vapor through the leaves, as water is transported from the growing medium with nutrients, through the roots. The nutrients are delivered into the plants, while a portion of the hydrogen and oxygen ions (from H2O) are assimilated through the plant. The majority of the water taken up escapes the plant through the leaves. Water pressure (turgor) inside the plant is what gives plants their rigidity and structure; as plants are after all, “bone-less.”
Light Energy = Growth: Healthy plants with ample CO2, water and nutrients will continue to photosynthesize under bright light conditions.
One of the most important things to understand about how these processes work on an individual basis, and as they do in harmony with one another, is that they need to be maintained in a balanced equation.
For example, the chemical equation in photosynthesis can be given as:
So if one of the pre-cursors in the reaction is lacking, for example, the plant has only three units of carbon dioxide relative to six units of water in the presence of bright light (radiant energy), the reaction can only work as high as a rate that three units of carbon dioxide will allow, with the remainder of the light and water being “wasted.” In fact, it may create a situation that is more than just inputs being “wasted,” it can actually create situations where the plant is running at a deficit.
In other types of situations, common to indoor gardening, when temperatures climb above 85°F, the rate at which respiration occurs (the burning of carbohydrates for energy) can exceed the rate of photosynthesis (creating carbohydrates). This creates a situation where by some definition, the plant is “working itself to death.”
Very bright light conditions are easy for indoor gardeners to supply using HID (high intensity discharge) lighting sources. This is usually the factor that creates an “imbalance” in the equation and relationship between the photosynthetic process, respiration and transpiration. The plant is saturated with intense light energy, while other factors such as carbon dioxide, temperatures, minerals and vitamins required by photosynthesis, etc. are not available in the same abundance. This imbalance puts the plant in a situation similar to excessive temperatures where the plant is working itself to death.
Bear in mind that modern indoor growers are putting incredible demands on the super-strains of plants that are cultivating. In nature similar types of crops may require four to six plus months to reach maturity in natural settings. Indoors, growers are driving the same types of plants to reach complete maturity in two to four months. That equates to twice the work that is required by the plant on a day-to-day basis! The demands placed on the plants by the environment supplied by the indoor grower are astounding when you consider the time frame it takes the crop to reach maturity versus in natural settings.
"Nature has created the perfect internal and inherent growing system (photosynthesis) within plants."
So how exactly are we accomplishing this incredible feat as growers? Well, those of us who accomplish it the most successfully are driving and fuelling this natural process through improved crop growth technologies. As growers, we are supplying an abundance of the factors necessary and in the correct balance to amplify the plant’s natural and inherent responses.
In today’s day and age, it’s easy to provide optimal light durations (day lengths) and incredible lighting intensities using readily available artificial lighting sources. HPS (high pressure sodium) lamps do a good job of producing lots of lumens, although they are not as rich and complete as the sun in spectrum. They also produce a lot of heat, which can be detrimental to plant growth, as we discussed earlier.
Air- and water-cooled lighting fixtures can drastically reduce the excess unwanted heat created, removing it at the source, rather than overheating the plants. Artificial lighting spectrums can be improved by using modern HID lamps that have their spectrums enhanced to stimulate plant growth rather than illuminate parking lots. While they are no match for the sun’s “solar nutrition,” they are an improvement.
High output T5 fluorescent lights can be very rich in spectrum, and are ideal for stimulating healthy plant growth in the earlier stages, and can in some instances be used to raise plants to maturity.
Heavy Loads: When plants are able to manufacture adequate supplies of chemical energy, heavy fruit loads may develop.
LEDs perhaps offer growers the best opportunity to provide very exacting light wavelengths for different growth phases. At present, it would appear that the technology itself is “smarter” than we are; growers and LED manufacturers alike are learning about what will work best at different growth phases, as LED fixtures can be tailored to provide very exact wavelengths of light. The technology goes far beyond the capabilities of what HID lighting can offer. LED diodes emit very negligible amounts of heat, reducing cooling requirements and costs. The fact that they run cooler allows for more efficient supplementation of carbon dioxide levels in the growing environment for faster growth rates and bigger yields, due to reduced air exchange requirements.
Carbon dioxide (CO2) for light reactions is usually the most limiting factor in indoor gardens, assuming cooling requirements have been accomplished with a high level of control. If growers are able to maintain optimal temperatures during the intense light cycle, plants will grow at noticeably increased rates when elevating the levels of carbon dioxide in the growing environment. Carbon is the biggest component in the dry weight of plants, and elevating carbon dioxide levels can have a direct effect on increasing dry plant weights at maturity. Fermentation, releases of bottled CO2, and generation of CO2 through gas-fired combustion are common methods growers may use to elevate CO2 levels in the growing environment for better results.
All of the areas discussed above are “exogenous” or external factors that can be controlled by the grower through the use of specialized mechanical equipment. Now what about the internal or “endogenous” reactions that are going on inside of the plant? This is where the real magic happens.
Modern, advanced nutrient manufacturers have dissected the internal responses and materials required to fuel and sustain high rates of growth for intense indoor growing environments. These “ingredients” have been discovered, refined and blended into exacting ratios to create crop feeding programs that help meet and stimulate the tremendous functional demands placed on crops by modern indoor growers.
The end result of the photosynthetic response is glucose, which is “burned” during respiration to release energy. There are crop feeding supplements that are able to supply relatively available sources of carbohydrates to plants when they are applied accordingly. This means that for example, in instances when the rate of respiration is exceeding the rate at which photosynthesis (during high light and warm conditions in the presence of CO2), the plant’s reserves of energy may not run at a deficit, allowing the plant to continue growth, rather than “shutting down” to prevent exhaustion or even plant death.
Consider high intensity activity in humans such as long distance running. Athletes load up on carbohydrates to provide their bodies with the necessary levels of energy to meet the high demands of the task they are placing on their body’s energy system. During the activity, runners breathe harder, requiring more oxygen. Plant growth has a similar demand for vital gas, although it is carbon dioxide rather than oxygen. If there is insufficient carbohydrates or necessary vitamins, minerals, gases, etc., the runner will finish poorly, or may not even finish at all in some instances. This is the case with plants.
After strenuous physical demands plants, like athletes, also require proteins to repair and build new tissue and energy transfer ways to supply and direct energy. This is where L-amino acids for crops come into play. Plants normally have to manufacture amino acids and other forms of reduced nitrogen to help build new tissue and create the energy transfer ways.
Growers who supply crop feeding supplements that contain broad spectrum of L-amino acids including lysine during times of great mass gains, for example in the peak bloom phase, are in fact providing crops with the necessary materials to get bigger faster. The plant will not have to work as hard to manufacture these proteins, as they are supplied at some level of availability. Note that microbes in beneficial bacteria and fungi help to improve this process. This would be similar to an athlete drinking a well formulated protein supplement after strenuous physical activity versus eating a steak. The athlete’s body will more readily assimilate select proteins in their ideal ratios, rather than expending energy to convert proteins supplied in cruder forms such as meats, to forms that the body can use to build and repair tissue. This quickly translates into greater mass gains in shorter time frames; something every indoor grower should aim to accomplish.
Vitamins, minerals, enzymes and other co-factors also play a strong role at which the rate of all the reactions required by the plant to grow may occur. Most minerals are supplied to the plant through the roots, carried up with water in the transpiration process (loss of water through leaves). Without these vital minerals, and in their correct ratios for the type of crop being grown, the rate at which photosynthesis may occur will decrease. This is why it is important to choose your crop nutrients carefully. The correct balance and a high level of availability under a wide range of growing conditions should be of careful consideration.
Plants typically manufacture their own vitamins, enzymes and co-factors, although in nature it has been demonstrated that these substances may also occur in the growth medium and be transferred to the plant for uptake and assimilation for functions. Again, this is typically assisted through beneficial microbes, which are available in modern formulations to inoculate indoor crops. These beneficial vitamins, enzymes and co-factors can also be supplied through specialized and well formulated crop feeding additives more or less directly to the plants.
Similar in concept to supplementing the crop with carbohydrates and amino acids for higher rates of growth and mass gain, additions of vitamins, enzymes and co-factors will benefit the crop. By using specialized crop feeding programs designed to promote bigger yields and healthier plants grown under intense artificial light and elevated carbon dioxide levels, the grower is helping to “balance” the plant’s internal equation that is dictated by the three key foundations to plant growth: photosynthetic activity, respiration and transpiration.
Now that you know more about what exactly is making your favorite plants tick, you may be able to improve your yields, growth rates and crop quality by respecting and maintaining an understanding of these very important principles. Keep them in mind when constructing the ideal environment for your plant with regards to light intensity and quality, temperature and CO2 levels.
Once you can maintain and manage the optimal external environment, your crop can take advantage of full spectrum feeding programs that have been designed specifically to satisfy the needs of your plants being grown in an accelerated environment. In fact, some crop supplements will help your plants to maintain a higher degree of health and growth rates, even in less than perfect environments. However, supplements are not a replacement to creating the optimal growing environment for your favorite type of plants. It is about harmony, balance and respecting the perfect inherent mechanisms for growth that nature has developed, and with understanding we may achieve our own personal yield of dreams.
And one more,,,,,,,,,,,,,,,,,,,,
pH Management for Optimal Results by Andrew Taylor
Optimum pH for nutrient solutions
For nutrients to remain dissolved and, therefore, available for uptake by roots, it is critical to maintain the pH between 5.0 and 6.0 with an absolute maximum of 6.5. When the pH of the nutrient solution is above 7.0, calcium, sulfate (and trace elements of copper, iron, manganese and zinc) can precipitate and become unavailable to the roots, causing plumbing blockages. High pH values, or those above 6.0, are to be avoided more than low values of 4.5 to 5.0. The effect of low pH upon the stability of nutrients is relatively insignificant.
The precise pH at which precipitation of macro-nutrients starts is determined by the combined concentrations of calcium and sulfate. Except for fertilizers low in calcium and sulfate this problem commonly occurs at pH 6.5 where the net* EC is 2.5 mS, or pH 7.0 for 1.5 mS solutions. Hence, to avoid precipitation, higher nutrient concentrations generally must be held at lower pH values. *Assume make-up water has nil EC.
In spite of this precipitation problem, some references advocate pH values well above 6.5 for some plant varieties, conditions that risk depleted concentrations of the above mentioned elements.
pH recommendation of 6.2 to 6.3?
Although 6.2 to 6.3 is a popular pH recommendation, which has no scientific basis. It appears to have gained mythological status from the early days of hydroponics when the only cheap means of measuring pH was the common ‘bromothymol blue’ pH indicator used for testing fish tank water. Interestingly, the lowest pH value able to be determined by that indicator is about 6.2. Hence, this value has unfortunately become an entrenched recommendation in some sections of the hydroponic industry.
Adjusting nutrient pH
The working nutrient pH should be checked at the following times:
- When working nutrient solutions are first made.
- After the addition of top-up water or additives, especially if they are highly alkaline.
- In re-circulating systems, pH should be checked on a daily basis because the uptake of water and nutrients causes pH to change (figure one).
How to minimize pH fluctuation
- Use a nutrient brand that is highly pH buffered, particularly when using highly alkaline water.
- Supply at least two gallons of nutrient for each large plant. Failure to do this will magnify pH (and EC) fluctuations, especially during hot and dry weather where water uptake and evaporation are excessive. Note, to avoid excess water uptake and evaporation; keep air temperature below 86oF and relative humidity above 50 per cent.
Step 1. Measure the pH: Use either a liquid pH indicator or an electronic pH meter (see sections below). Before measuring the pH, ensure that the nutrient is well stirred and that the sampling container is clean.
Step 2. Choosing a target pH: Note that it is inconvenient and unnecessary to hold pH at a single point value. Therefore, choose a target pH that minimizes the amount of pH maintenance:
Step 3. Adjusting the pH: Add a small amount of pH down or up product*. Then stir well and check pH. Repeat this process until the target pH is achieved.
*Important: Pre-dilute the dose into one quart (or at least 100 fold) of water before adding to nutrient, then rapidly stir the nutrient as you add this mixture. Failure to do this may cause permanent precipitation of essential nutrients. Also, if accidental overdosing to above 6.5 occurs, reduce the pH back to below 6.0 as quickly as possible using pH down.
Handy hints for adjusting nutrient pH
1. Add “high pH” (alkaline) additives before adding nutrient: Most additives will affect nutrient pH at least slightly. The best technique to adopt with those that elevate pH significantly is to add them to the water and adjust the pH down to 6.0 prior to adding the nutrient.
The less preferred but simplest alternative is to pre-dilute the additive in a separate volume of raw water. Then once this solution is added to the nutrient solution, quickly lower the pH to below 6.5. Note that a white cloudy precipitate (calcium sulfate) may form when the pre diluted additive initially merges with the nutrient solution. However, because the initial particle size of the precipitate is small, it will usually re-dissolve if the pH is immediately re-adjusted.
2. Do not pre-adjust pH of raw water: Note that the pH values being discussed here are the values of the working nutrient solution, not your make-up water. Unless your make-up water has a high alkalinity, do not bother attempting to adjust its pH prior to the nutrient being added. If you attempt this procedure you will typically get wild pH swings either side of the pH target without ever landing on the target value.
3. Estimating the volume of acid (especially for larger systems):
Step 1. Take a one quart sub-sample (or known volume) of working nutrient.
Step 2. Add a few drops of pH indicator (figure two ‘a’
.
Step 3. While stirring this solution, measure the volume of acid required to turn this solution yellow – figure two ‘b’ (Yellow indicates a pH of 6.0 with most broad range liquid indicators).
Step 4. Multiply the volume of acid* by the volume of nutrient in your reservoir. That calculation will give you the volume of acid required to adjust the entire volume down to pH 6.0, for example.
Measuring pH with ‘indicators’Step 2. Add a few drops of pH indicator (figure two ‘a’
.Step 3. While stirring this solution, measure the volume of acid required to turn this solution yellow – figure two ‘b’ (Yellow indicates a pH of 6.0 with most broad range liquid indicators).
Step 4. Multiply the volume of acid* by the volume of nutrient in your reservoir. That calculation will give you the volume of acid required to adjust the entire volume down to pH 6.0, for example.
pH indicators are undoubtedly the simplest and most reliable method of measuring nutrient pH. Although they will not distinguish between, for example, a pH of 5.2 and 5.3, wide range indicators with good color resolution can be:
- fast and user friendly
- extremely accurate and reliable
- economical
pH indicators work on the principle that the color produced by the particular dye used in the indicator formulation is dependant on the pH of the solution (figure three).
Experience shows if you are aiming to adjust pH to 5.5 (orange) then an accuracy of +/- 0.2 is achievable. Because of their fundamental accuracy, reliability and easy of use, wide range pH indicators are the preferred method for measurement of pH in nutrient solutions. Note that pool and aquarium pH indicators are usually not suitable because unlike broad range indicators, they do not operate below pH 6.0.
Taking pH readings
Step 1. Before measuring the pH ensure that the nutrient is well stirred, especially after pH up or down products are used. This is one of the most common mistakes made when testing pH (or conductivity). Also, ensure that the sampling container is clean.
Step 2. Using the sampling vial, remove a small sample of nutrient from the nutrient reservoir, add a drop of the indicator, mix, and then compare the final solution color with those on the colored reference chart (figure three).
Step 3. If the pH is not between 5.0 and 6.5, adjust it immediately.
Measuring pH with pH meters
pH meters employing a glass electrode are useful for precise pH measurement in nutrient solutions but require frequent calibration, proper storage and handling to ensure accuracy and reliability. The principle on which such meters operate is based on the fact that when glass of a certain composition separates two aqueous solutions having different hydrogen ion concentrations, a voltage is developed between the two faces of the glass. The electronic meter is simply a very sensitive voltmeter which measures that voltage but is calibrated in terms of pH units instead of volts.
Obtaining pH readings
Step 1. Make sure the meter is calibrated.
Step 2. Remove a ‘representative’ sample from the nutrient reservoir (figure four):
- Stir the nutrient thoroughly prior to sampling.
- Ensure the sampling container is clean.
Step 4. If the pH is not between 5.0 and 6.5, adjust it immediately.
Step 5. When complete, rinse the electrode with distilled water. Store the electrode in a proper storage solution when not in use.
The website is the same as the title of this thread, Maximumyield.com. There are lots of good articles there and it is like an online magazine or Ezine, they have hundreds of great articles as well as several charts (click extras link), I hope everyone enjoys them as much as I did
Riddle Out
