SATORI F2 X QUERKLE MALE PROJECT

Levinthelyf

Active Member
Yea i cant wait to get my first grow going. Just waiting on these clones to root. Going to transplant them into one gallons. Veg for 2 to 3 weeks then going to flower. Hoping to run 72 plants my next run doing SOG. Would of done it this time but didn't have enough growth for that many clones.
 

im4satori

Well-Known Member
Yea i cant wait to get my first grow going. Just waiting on these clones to root. Going to transplant them into one gallons. Veg for 2 to 3 weeks then going to flower. Hoping to run 72 plants my next run doing SOG. Would of done it this time but didn't have enough growth for that many clones.
4x8 tray 32 plants veg 1 week 10 days max
4x8tray 50 plant veg 3 days max

how high is your ceiling?

you veg for 3 weeks you better have a 12ft ceiling

or are you adding more lights and larger grow?
 

Levinthelyf

Active Member
My 4x8 can hold 72 one gallon pots. My pots a 7.5"x7.5" square. So that fills the tent with a little room to spare. When I say veg I'm including the week and couple days of rooting in the humidity tray. So week and a half in humidy try and week and a half in veg. Then switching to flower.
 

im4satori

Well-Known Member
My 4x8 can hold 72 one gallon pots. My pots a 7.5"x7.5" square. So that fills the tent with a little room to spare. When I say veg I'm including the week and couple days of rooting in the humidity tray. So week and a half in humidy try and week and a half in veg. Then switching to flower.
that's still to many plants my friend

i will often fill my space with a few xtra and thin those that are slow to take off

i give them a few days veg even thou they don't need it
i gave 2 weeks veg just to get clones from the undersides..plants ended up 4ft tall

most strain,,, veg 3weeks the plant will fill a 2ftx2ft area when done and that's with pruning
 

Levinthelyf

Active Member
that's still to many plants my friend
My boy that gave me my LSD has been doing it for about a year and 2 months. He is running 2 4x8 and 2 5x9 flowering the 4x8 one month and the 5x9 the next doing SOG the whole time. That's why I want to do my first grow like his bc i have seen him do it.
 

im4satori

Well-Known Member
I would do something more like 32 plants 10" pots veg 2 weeks (don't need it)
plan for tall plants and remove all the lower growth that's not going to be healthy since it wont get much light

tomorrow I will show you a pic a 16 plants in a 4x4 tray and they got 2 weeks veg
there almost 5ft tall
granted they where tall plants ... I have grown other strains that didn't stretch as much but grew wide

your plants with that much veg and in soil are going to be root bound in those pots
 

im4satori

Well-Known Member
the whole point of a SOG is not to veg at all
get them rooted and established and go

there used to be a guy on another site named OZ from many years ago... I modeled my first grow off his journal

I still have his entire journal saved on word

let me see how much work it would be to copy and post it....I will get back to you
 
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im4satori

Well-Known Member
please note these are not my words..this is a copy paste of another grower named OZ from a decade ago

I usually flower 25 to 30 plants per table under 1200 watts of HPS, I yield around 1oz to 1.5 oz dry per plant keeping myself in a ready supply of exquisite marijuana, all homegrown

Over the next few weeks I will keep returning to my little patch of green and I will take closeups of the plants ripening and growing so people can learn the highly productive and high quality practises that I have made it my lifes work to learn and improve, I will also show you some of my current breeding projects and odds and ends that occur in my garden.

I welcome any questions also, from beginner to expert Id love to hear your comments, both good and bad

Oz



Some whiteskunk plants at around 6 weeks at the vesy front of the shot, these are roughly 16 inches in height after being set to flower at 7 inches, these are producing copious amounts of resin now they are in their final 2 or 3 weeks. Adjacent to them are some more WhiteSkunk at the beginning off the 3rd week of flowering, slightly taller at around 20 inches in height from being flowered at 9 inches



A look at the 3 week plants now, we can see a heavily seed laiden and pregnant AK47 mother in an ajoining table too.

Node space remains tight under the purely HPS lamps and provides just enough room for the genetically determined fist like clusters the Whiteskunk produces, by the end of flowering there will be little to no space and tight, hard resinous bud.




The SOG canopy, beautiful and perfectly healthy plants swaying in the breeze. The flowering marijuana plant is such a beautful thing, the lush greens and hues of purple around the lateral and distal leaf segments in this phenptype of the whiteSkunk was what initially attracted me to it, that and the massive oily nugs of course


these are at week 4 or so, a little to much orange in this picture as I jhad the lamps running, this table has GWS,ak47, g13, Whiteskunk in it, the GWS, G and others are visible at the front of the picture

Attached Thumbnails




HPS lamps are perfect for vegetaing motherplants, I have 5 and 6 year old moms in here, as you can see the plants just love the light and ideal conditions I have provided. Keeping very healthy motherstock is a prerequisite for Sea of Green farming, our demand for fast growing clones is so high and as I said, Im constantly on my toes keeping my technique up.

All these plants get fed nutrients at 1200ppm every other watering, so I water with nutes every second watering, they get fresh in between times and are flushed once per month. Ph sits at 5.7 to 5.9.


Sure Knore here is a few pics of the tables, you can see an 8 inch clone been planted in here which has been under 12/12 for 1 week now, the table floods to 3 inches in height on average, the watermark in the next pic indicates the level to which the tray floods, I have had these pots for 4 years or so too so they are well worn


Oz gives SOG a thumbs up




Hello guys

Im pushing 8600 fc over each area, each table has 1200 watts over 12 sqr foot. I havnt had any problems with them being rootbound as they get fed twiice daily, the roots sit in a bath of nutrient so the surface area exposure is ggood, there is also a lot of oxygen in the mixture I use as it dries out during waterings.
I use normal fluros and a humidity dome ot take clones, I clean the bottom inch of each clone, dip it in root powder and put it in a rockwool cube, just the oldschool way of cloning, nothing fancy but it gives me roots in around 5 to 7 days. I usually take the cuts and 10 days later they hit the tables, they are from anywhere between 6 and 9 inches in height I have decided after measuring a few, most are 8 inches.


As promised here is a few updated shots, we are in week 6 right now and you can see the buds are filling out totally, producing lots of sweet stick resin, the smell is strong and the nutrient utilization has slowed, they are sucking up the water though. Ive dropped the strength to around 1100 ppm with a PH of 5.7.


I say another 2 weeks, its often not necessary to let your plants go right to total orange in the leaf, harvesting at between 25% and 50% mature red trichs can give you some very psychoactive marijuana....


i. 20mins teice per day using Rockwool floc, for expanded clay or clay balls flood for 20mins every 4 hours.

ii. I use the main stem off my mother plants to clone, these give the fastest and highest yielding growth and flowering

iii I use Canna nutrients and Canna Pk 13-14 for all my grow and bloom needs

iv High plant numbers are a legal consideration, the necessity to have high numbers of healthy clones can be a lot of work also.


Hello sweetleaf420

1. I get penetration right to the bottoms, its a SOG grow. 1200 watts over 12 sqr foot ie., 1 table.
2. Absolutley no idea whatsoever, its a 65 litre res.
3. Depends on the strain, from 12 to 36 inches at finish/harvest. Clones are from 8 to 10 inches depending on strain.



Hey S2, i use granular rockwool, its like rockwool potting mix, it holds a reasonable amount of solution and has good drainage also.

My moms are in 8 inch squat pots filled with perlite and vermiculite mixture. They are handwatered



Helo Das Masser

You are obviously very new to growing so I invite you to take a read of our grow guide. Its elementry reading and will help explain some of the concepts involved in growing marijuana for your personal use. You have raised some interesting points that with some further reading and understanding may help you to grow and post some pictures for us to see your praticing of our craft . I have never seen any of your pictures so its hard for me to gauge your level of experience or even if you have ever grown before. Still ill take the time to help you here as you obviously are interested.

You have mentioned a couple of things here which the others have found amusing, Ill take the time to briefly explain them to you so you arn't fooled into making the same basic errors again. Its all experience man, try not to take it to hard

Quote:

I have a ques. Is it just the lighting or do the fan leaves have lots of brown spots?? They get that from over watering

Ahh chlorosis and narcrosis, those two processes of chloryphill degradation. Usually occuring in the last 2 weeks of the flowering cycle as the remaining nitrogen and sugars are used by the plant as I run fresh water. The plants had not been watered for 1 week in those shots, thus the narcrotic spots as the leaf energy was used up prior to harvest. Overwatering problems present as narcrotic spots in the lower leaves, not the tops


Quote:

Another thing is that you are probably blowing on them too hard. In one picture the leaves look wilted and I'm sure you shut the fan off to take the picture(I do the same thing). They should still be perky and angled up.

I made alot of the same basic errors when I was starting out too. Leaf posture is effected by many factors, during the transitional veg to flowering period the fans and dorsal leaves will often stand to attention, with correct conditions sufficient resin will accrue on the topside leaf planes to weigh these leaves down, couple this with nutirent withdrawl later in the piece and the leaves begin to sag and look wilted.

Its funny that you are suggesting leaf wilt due to air movement, again as you are a beginner its an easy mistake to make. Leaf wilt results from excess heat and hyper transpiration, not excess movement in the grow room. Again a read of our elementry grow guide will help you understand these 'entry level' concepts

Quote:

Try to find some Mylar to get more light bouncing around in there.

My walls are lined and as Im using horizontal twin parabolic reflectors my light refraction rate could not be higher. Im clocking 10,000 fc over my garden. This is ideal. If you would like to understand how light is absorbed and optimum reflection levels we have some great beginners articles in our Library. Take a read, they are illuminating

So thanks for raising those points and for he nice comments Das Masser, as a grower I like being able to educate new growers and beginners as it reasures me I keep my knowledge current

Grow on


Hey st0ney: They dont have any issues with being rootbound that I have seen and I have grown them to around 5 foot in these pots using the same amount of medium, the feeding gives them enough to encourage a large mass without any issues developing.

'edStash: Nah no foliar feeding, just the Canna grow and bloom nutes and their pk 13-14. I also add silica for the first 3 weeks as it gets them off to a nice start in regards to limb structure.

__________________
 
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im4satori

Well-Known Member
you can see from the pics the canopy is nice and even and the plants are spaced close but don't look like there one big ball of weeds

if you space them to close they'll just stretch to holy hell competing with each other for light and space... the lower growth will be unhealthy
 

im4satori

Well-Known Member
levi16.png
Sea of Green (SOG) is the theory of harvesting lots of small plants, matured early to get the fastest production of buds available. Instead of growing a few plants for a longer period of time, in the same space many smaller plants are grown that mature faster and in less time. Thus, less time is required between crops. This is important to you when the electricity bill comes each month. One crop can be started while another is maturing, and a continuous harvest, year round can be maintained. 4 plants per square foot will be a good start for seedlings. 1 plant per square foot will allow plenty of room for each plant to grow a large top cola, but will not allow for much bottom branching. This is OK since indoors, these bottom branches are always shaded anyway, and will not grow very well unless given additional light and space. The indoor grower quickly realizes that plants that are too tall do not produce enough at the bottom to make the extra growing time used worth while. An exception to this rule would be if it is intended the plants are to go outside at some point, and it is expected that the light/shading issue will not be a factor at that point.


The plants, if started at the same time, should create what is called a "green canopy" that traps most of the light at the top level of the plants. Little light will penetrate below this level, since the plants are so close together. The gardener is attempting to concentrate on the top of the plant, and use the light and space to the best advantage, in as little time as possible. Use of nylon poultry fence or similar trellising laid out over the green canopy will support the plants as they start to droop under the weight of heavy fruiting tops. Stakes can be used too, but are not as easy to install for plants in the middle and back of the room, where reach is more difficult.

It is easy to want big plants, since they will produce more yield per plant, but it is usually better with limited space to grow smaller plants that mature faster and pack into smaller spaces. Sea of Green was developed in Holland. Instead of fitting 4 large plants in that small room, fit 12 small ones on a shelf above 12 other small plants. These plants take only 3-4 months to mature from germination to ripe buds, and harvesting takes place constantly, since there is both a vegetative and flowering area devoted to each, with harvests every 45-60 days.

It is not the size of the plant, but the maturity and quality of the product that counts. Twice as many plants grown half as big will fill the grow space twice as fast, so harvests take place almost twice as often. Get good at picking early flowering plants, and propagate only those that are of the best quality.

6" square containers will allow for 4 plants per square foot. You may also gauge by the size of your growing tray (for passive hydroponics); I like kitty litter boxes. ($3 each at Target) Planted 4 per square foot, (for vegatative seedlings) a 12 sq. ft. closet will hold 48 seedlings on one shelf. In my case, I use 4" rockwool cubes that fit into kitty litter pans @ 12 cubes per pan. I can get 5 pans onto a 12 sq. ft. closet upper shelf, so that is 60 seedlings on one small shelf!



For flowering indoors, 1 plant per sq. ft. is a good rule of thumb for SOG. If less plants are grown in this size space, it will take them longer to fill the space, thus more electricity and time will be used to create the same amount of product. If more than one plant p.s.f. is attempted, the grower will soon find that plants thus crowded tend to be more stem than bud, and the total harvest may be reduced, so be cautious.

It is good to avoid "topping" your plants if you want them to grow as fast as possible. It is better just to grow 2 or 4 times more plants, since they will produce more, faster, in the same space. Also, "training" plants with twist-ties is a great way to get them to bush out a bit. Just take any type of plastic or paper twist tie and wrap it around the top of the plant, then pull it over until the top is bent over 90-180 degrees and then attach this to the main stem lower on the plant. Do this for one week and then release the plant from it is bond. The plant can be trained in this fashion to take less vertical space and to grow bushier, to fill the grow space and force lower limbs to grow upward and join the green canopy. This technique takes advantage of the fact that if the top is pulled over, it creates a hormonal condition in the plant that makes it bush out at all lower internodes.

Sea of Green entails growing to harvest the main cola (top) of the plant. Bottom branches are trimmed to increase air flow under the "blanket" of growing tops. Use these cuttings for clones, as they are the easiest part of the plant to root. It is also the fastest part of the plant to regenerate after flowering has occurred.
 

im4satori

Well-Known Member
not my words...copy and pasted;


Humidity plays a major role in plant growth, and it's effects are often underestimated or overlooked. To the right you will see the "tools of the trade" for controlling humidity...the dehumidifier and the humidifier.

Plants breathe through tiny openings on the undersides of their leaves called stomata. Plants can (and do) open and close their stomata under certain conditions, for example if heat becomes excessive and causes a plant to start loosing more water than it can take up, the plant will close it's stomata to slow down the water loss.


The ideal humidity range for healthy plant growth is 50% humidity, plus or minus 10%.


Unfortunately, by closing the stomata and slowing evaporation the plant also has slowed down it's cooling mechanism. This causes heat to build up in the plant tissue, and in temperatured too hot the plant actually cooks itself. It is important to understand the opening and closing of the stomata and how it, in turn, controls plant transpiration.

Plant transpiration is how plants breath. Plants do not have lungs, however, so when molecules of gas and water vapor are released from the stomata they tend to just hang there in the abscence of any breeze. That is why it is so important to have box fans or oscillating fans in a garden to circulate the air (in addition to exhaust fans). These fans are actually like the plant's lungs, and without them the plants would have no way of moving fresh CO2 molecules into contact with their plant tissue. The plants would slowly choke on their own transpired gasses and water vapor.

As water evaporates from the surfaces of leaves, the surface tension of the water molecules tend to pull the next water molecule along behind it, up through the plant's veins. Water is pulled up through the plant stem, which is pulled from the plant's roots. This creates a negative water pressure in the root zone and allows the roots to suck moisture up out of the root zone like a straw. The process of water absorbing into the plant through the roots is known as osmosis

Which brings me back to humidity. Water vapor is humidity. As a plant transpires, the humidity immediately surrounding the leaves will become saturated with water vapor. Now, the entire plant transpiration cycle is controlled by evaporation. When gasses surrounding a leaf become saturated with water vapor (100% humidity), there is no place for the next molecule of water vapor to evaporate to.

The end result is that water vapor is not evaporating, so water is not being drawn up from the root zone...and neither are any nutrients. If nutrients are not being taken up, than developing fruits are not getting the food they need to be healthy. This is exactly why high humidity will cause blossom end rot in fruiting tomatoes just like a Calcium deficiency. It is another reason why it is so important to keep box fans and oscillating fans in the garden area to keep the air circulating.

So, evaporation controls plant transpiration. High temperatures and low humidity therefor both cause fast transpiration. Fast transpiration means your plants will be taking up and using lots of water (and nutrients). This is fine, unless you were feeding your plants strong to begin with. Your plants can only handle so much fertilizer within a specific period of time.

So if you now have warm temperatures, low humidity, and fast transpiration rates you may find your plants are using a little too much fertilizer a little too quickly. Leaf tip burn is usually a sign of this. Under these circumstances you can feed your plants with a weaker nutrient solution.

Or, if all other plant growth influencing factors are in their ideal ranges, you can try to maximize plant growth by adding CO2 (in which case you should experience heavy plant growth without showing any signs of stress or damage.
 

im4satori

Well-Known Member
not my words...copy and pasted


"Fine-tuning temperature and water for maximum quantity and quality.

Why waste light and electricity growing stem? Stretched-out plants are the bane of indoor growers. There are several ways to reduce internodal length and thus grow denser, more efficient buds.


Temperature control

The easiest and most under-used way to control internodal stretch is temperature control. Plant internodal length is directly related to the difference between day and night temperatures – the warmer your day cycle is as compared to your night cycle, the greater your internode length will be. The opposite also holds true; the closer your day and night temperatures, the shorter your internodes will be. Ever notice how as the warmer summer months approach, your plants begin to stretch? Part of this problem may lie in an overall hotter grow-room, but a larger factor is the increased difference between day and night temperatures.

Lets look at putting this to play in your grow room. Maximum temperatures should ideally never rise above 78.8°F, so you must do everything you can to prevent your room getting too hot (run lights at night, use exhaust fans, air conditioners, etc). An ideal temperature range is 75-77°F when the lights are on, and 71°F when the lights are off.

The temperature technique is most effective under a 12/12 light regime, which is ideal as this is when cannabis stretches the most. When the light cycle is brought to 12/12 we will raise the night temperature to the daytime level of 75-77°F. Space heaters on timers work well for this, and max/min type thermometers are ideal for
tracking temperatures.

It is during the first 2-3 weeks of the flower cycle that most strains begin to lengthen internodes, making it a very important time to control temperature, as this is when the framework for future colas is built. After this 2-3 week window we need to drop the night temperature back down to 71°F, as this is where the plant is happiest.


As floral development begins we need to keep in mind that the total size of your buds is determined largely by average daily temperature, provided it does not exceed optimal. So if you are letting your day temperatures drop below 75°F or your night drop below 71°F, you are costing yourself in overall weight and harvest.

Once your buds have reached optimal size and and you have begun the flushing period, you may consider dropping temperature down to 62-66 F for the final week or two. This drop in temperature triggers anthocyanin production, which intensifies the color of the floral clusters and makes for a showier bud, especially with "purple" varieties. This final temperature change is not always feasible and can be omitted.

For extreme height control you may even use warmer night temperature than day, but be very careful when running settings like this, as even a zero difference between night and day temperatures will lead to leaf chlorosis (yellowing) after 2-3 weeks.

Some things you will notice while using this technique are a change in the leaf angle, upwards during warm days and downwards during warm nights. There is also the chlorosis if this is done for too long. Neither of these symptoms is nutrient related and will fix themselves when the temperature is changed back.


Moisture and conductivity

Whether you're growing hydro or in soil, the electrical conductivity (EC) and moisture of your medium are two key elements that should be manipulated to meet your needs. Both of these factors are controlling the same thing; the ability of a plant to uptake water and nutrients from the growth medium. (EC measures the level of fertilizer salts in the water.)

A plant grows by first dividing cells then expanding them, and in order to do this it requires water. By limiting the amount of water available to a plant you limit the expansion of cells. This can work for you by keeping your internodes close together, or against you by limiting bud growth. Both the amount of water you give your plants and the EC at which you grow them control the uptake of water.

A plant's roots act much like a pump, using osmotic pressure to move water into the plant. In order for this to work there must be a larger concentration of fertilizer salts in the plant's roots than in the soil or hydroponic solution, so when the medium's level of salt rises above the roots', the plant will wilt. Raising the salt level in the medium closer to that which is in the roots limits the water availability just the same as if we had provided less water.

During the vegetative stage we want our plants to form very tight internodes, especially under artificial lighting. By allowing the EC to drop below ideal during this stage we are wasting valuable space growing stem instead of bud. Most marijuana strains are happiest when grown at an EC of between 1.5 and 1.8, but different strains have different preferences. Try growing one of your plants using straight water for a week or so, you will see the internode length stretch dramatically compared to the ones on a regular fertilizer regime.


Hydroponic tomato growers sometimes will grow their transplants at extremely high EC's (up to 6 EC!) in order to get really nice stocky production plants. Please note that when doing this they use special nutrient formulas designed for this purpose, most of which have potassium to nitrogen ratios of 4:1, much higher than normal, as too much nitrate at this high an EC will easily damage a plant.

(Try this formula if you're interested: calcium nitrate 7 grams, potassium nitrate 0.095 grams, potassium sulphate 9.25 grams, mono potassium phosphate 2.2 gram, magnesium sulphate 5 grams, micromix .02 grams. Slowly raise your EC during veg stage, I would not recommend going above 3 or 4 EC. This is experimental! Do not try on all of your plants at once until you are sure your strain can handle it. All of these ingredients should be available at your local hydroponics store, it is usually called "six pack formula". Be sure to bring your EC back down once you enter floral stage, by the time tufts of pistils are visible you want to be at your ideal EC of 1.5-1.8.)

Try not to change the EC too quickly as a sharp drop can cause root damage. This also goes during your final flushing period when you want to eliminate all fertilizer from the medium – lower the EC over a couple of days, as the sudden change in salt level will harm the roots.

When growing hydroponically, the only way of manipulating water availability is with the EC, while in soil we may also use the moisture level of the medium to the same ends. Many growers are under the mistaken impression that the EC and pH of their nutrient solution remains the same when applied to the soil. This in not the case, and you must test the soil in order to have a true
picture.


To test your soil, take a sample from the center of the root zone at the side of the pot (don't worry the torn roots will be fine). Mix the soil with 2 equal parts distilled water and let sit for 20 minutes. Once the time is up take an EC reading and multiply this number by 2.4 (this takes into account the dilution and the pore space factor) this will give you an accurate picture of the EC the roots are actually being exposed to. The pH should also be checked at this time. It is not feasible in soil to maintain an exact EC at all times, what we need to try and avoid is EC's climbing much above what we want and plants going for long periods with very low EC's.

A frequent mistake marijuana growers make is over-emphasizing the need for a plant grown in soil to dry out completely between waterings. Cannabis does like dry feet but this simply means that the root zone must not be kept extremely wet at all times. Keep in mind that if the soil has an EC of 1.8 and then dries out completely the amount of salt remains the same, causing the EC to double or more.

As a general rule, during the vegetative stage you should keep your plants a little on the drier side as this will restrict cell elongation, creating a shorter noded plant structure capable of creating a dense bud cluster in the floral stage. (Unless of course you are using the high EC method described above, in this case you must not let your soil get too dry because of the increased fertilizer level you will create.) Maintain this level of moisture into the first 14 to 20 days of 12/12 to minimize internode stretch.

As soon as early flowering begins you need to increase soil moisture to a nice evenly moist (not soaked) level to maximize bud expansion. Growing marijuana too dry during this stage will adversely affect your overall yield, as will having too high an EC in the medium.

In these times of government oppression we must make the most efficient use of available growing space in order to produce the copious amounts of cannabis necessary to overflow the boundaries placed upon us. Control your cannabis!"
 

im4satori

Well-Known Member
not my words...copy and pasted

Day-Night Temperatures
For the majority of flowering and fruiting plants produced hydroponically, plant growth and flowering will be optimal under conditions where the night temperature is lower than the day temperature. Most plant species exhibit these 'Diurnal rhythms' where certain plant process such as the rate of growth of the flower buds, stomata opening, discharge of perfume from flowers, cell division and metabolic activity, occur more rapidly at a certain time within a 24 hour period. For example, photosynthesis in most plants is known to reach a maximum just before noon, and cell division also seems to always reach a maximum just before dawn. Many species flower or grow well only when temperatures during the part of the diurnal cycle that normally comes at night are lower than temperatures during the day. Also light given during the normal night period may actually inhibit some plant processes.



Plants such as tomatoes seem to be particularly sensitive to the alternation in temperature between day and night: they produce more flowers when night temperatures are lower than day temperatures - this effect in plants is called 'Thermoperiodism', and is common amongst many plant species. Pepper plants also require lower night than day temperatures for good production, it has been found that many more buds on pepper plants will actually develop into open flowers when night temperatures are at least 6 C(11F) lower than day temperatures. Where day and night temperatures remain at similar levels on a long term basis, flowering and fruiting can be adversely affected, particularly where temperatures are warm. Bud, flower and fruitlet abscission is much more common on crops which do not receive lower night temperatures and this often limits production of crops such as tomatoes and peppers under tropical conditions.



Night temperatures for most plants are optimal at around 18 C (65F) too 24 C(75F) lower than day temperatures, provided day temperatures are held at optimal levels for photosynthesis. At night, where the 'sinks' which receive the assimilates (sugars) produced via photosynthesis, become cooler, transport of sugars into these is promoted. 'Sinks' on most plants are the developing flower buds, flowers and fruit which have the greatest affinity for the sugars produced by the plant. The 'Source' is the producer of the assimilates - usually the leaves, but sometimes also the stem in some plant species. So cooler 'sinks' get more assimilate pumped into them at night than if they remained as warm as they were during the day light hours.



Apart from the physiological effects on plant growth and flower development, having a lower night temperature setting has other beneficial effects on plant processes. Firstly root pressure is greater at night under cooler conditions - this increases the pressure in the xylem vessels, so that calcium and other plant growth compounds which are carried in the xylem stream are forced out to the leaf tips and into developing buds, flowers and fruits. This turgor pressure is often essential in the prevention of tip burn as it ensures calcium is carried to the very edges of the leaves. Often, this root or xylem pressure can be seen in the form of 'guttation' which are visible droplets of water which can be seen at the tips of leaves on plants in the early morning. It is this root or xylem pressure which also acts to 'pump up' the plant during the cooler night temperatures particularly after a day when transpiration rates and warm temperatures have resulted in some wilting and loss of turgour.
Maintaining cooler night temperatures also ensures that plant respiration does not occur at too greater rate. Respiration uses up valuable assimilates and the rate of respiration increases rapidly with temperature. Under very warm night temperature conditions, night respiration can burn nearly as much assimilate as has been produced via photosynthesis and can severely limit plant growth.
 
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