Flushing Question!.

EL Connoisseur

EL Connoisseur

Well-Known Member
Hi cannaculties!..I was wondering and I have a question about flushing.. should i drop down the ec level immediately and keep it there for a week or so(in coco)?..or should i give plain phed water for a week to low the ec periodically and at the end of the week it should be at the water's level.?.which from the 2 methods is the right?..
Thank you very much!
Appreciate your help..
-Keep Growin'-
 
Dr. Who

Dr. Who

Well-Known Member
Flushing for better taste is a MYTH!

YOU CAN NOT FLUSH NUTRIENTS FROM A PLANT!

I got asked about this in a PM by a member after seeing the disaster another thread became. He asked where to find books and papers on "flushing" and said he might try the "fade".

Here's my answer to him......I felt it needs to be seen,,,,,,again!

Your looking for post grad work. You would do better to search papers......The thing is, NOTHING in agriculture gets 'flushed" and that leads to little to no research in the area. You see, the thing is, the whole "idea" of "flushing is nonsense! Plants don't work that way! They do not take up nutrients or salts as most of you think of them! They do not "store" them in the sense you think of them! Not only that, but the nutritional "stores" in a plant are not in buds or budding or flowers! NO amount of "flushing" will "exchange" plant "stored" nutrition back "out" of the plant! Scientifically impossible by the way most of you guys understand......Ok, that's my word on "flushing". (No one listens to this in threads if they don't want to hear it or accept it.)

Now then, you propose the "FADE TO FINISH" method. Great idea in theory but, and this IS a BIG BUT! Remember when I said above that "the nutritional "stores" in a plant are not in buds or budding or flowers!" ? This shoots that theory in the ass right away. You see the main amount of stored nutrition is in either the roots and the rest in leaves and some in small amounts in transit in the phloam (the sap that actually moves the nutrients around the plant)......

Now when you "starve a plant" it will draw from it's self by actually breaking down the needed parts of it's self to do an "emergency" attempt to reproduce! (This can happen in certain plants even in veg! A kind of last ditch effort to continue the species.)

With that in mind you take the fact that the plant is not "moving" nutrients "out" of buds, but into them to speed growth and as fast as it can - "reproduce". This single minded process the plant now puts it's self on causes the plant to stress it's self. This self induced stress can, in many cases if done long enough, lead the plant to go bisexual, and produce "banana's" in a last ditch effort to reproduce and "carry on the line" and produce seeds...

Basically put, In reality you are moving nutrients that you're "attempting" to get rid of,,right to where your trying to remove them from! You are also stressing the plant in the way for "Herming" to actually happen easier!

I and many others that have tried to convey this actual plant science, are called everything you can think of and those 'impossible of understanding these facts", fight so hard against us that many of us have simply chosen to avoid the issue or don't fight to hard.

Anyway, there you are in as short and sweet and as simple/understandable as I can...

The thing is you have to understand Botany and Horticulture (and there are LOTS of subsections to those that are involved here) to truly put together the pieces of the puzzle to get your head wrapped around the idea that flushing and the "fade" don't work for what they are intended or alleged to actually do!

There you go Mods, nice, polite and to the point. (Sorry about the other thread Sunni)

There you go, Now have at it!
I'm stepping back to watch the circus.

Read this too!

https://www.rollitup.org/t/the-truth-about-flushing.409622/
 
Venus55

Venus55

Well-Known Member
Another long but very interesting read:

There have been a lot of debates on this forum about flushing and there is a lot of misunderstanding about it in general flushing has its place in gardening and in the real world (other than MJ forums) is referred to as leeching.

This will be a long read but I hope it will set the record straight for everyone, this has been posted in several places here but I am putting this post together to clear things up a bit for all of you.

first a ditty from Sensi Seeds with links verifying,,,

From an administrator at Sensi Seeds

"Advanced - Flushing

A critical look at preharvest flushing

Pre harvest flushing is a controversial topic. Flushing is supposed to improve taste of the final bud by either giving only pure water, clearing solutions or extensive flushing for the last 7-14 days of flowering. While many growers claim a positive effect, others deny any positive influence or even suggest reduced yield and quality.

The theory of pre harvest flushing is to remove nutrients from the grow medium/root zone. A lack of nutrients creates a deficiency, forcing the plant to translocate and use up its internal nutrient compounds.

Nutrient fundamentals and uptake:

A good read about plant nutrition can be found here.

Until recently it was commonly thought that all nutrients are absorbed by plant roots as ions of mineral elements. However in newer studies more and more evidence emerged that additionally plant roots are capable of taking up complex organic molecules like amino acids directly thus bypassing the mineralization process.

The major nutrient uptake processes are:

1) Active transport mechanism into root hairs (the plant has to put energy in it, ATP driven) which is selective to some degree. This is one way the plant (being immobile) can adjust to the environment.

2) Passive transport (diffusion) through symplast to endodermis.

http://www.biol.sc.edu/courses/bio102/f99-3637.html

http://www.hort.wisc.edu/cran/Publications/2001 Proceedings/min_nutr.pdf

The claim only;chemically ferted plants need to be flushed should be taken with a grain of salt. Organic and synthetic ferted plants take up mineral ions alike, probably to a different degree though. Many influences play key roles in the taste and flavor of the final bud, like the nutrition balance and strength throughout the entire life cycle of the plant, the drying and curing process and other environmental conditions.

3) Active transport mechanism of organic molecules into root hairs via endocytosis.

http://acd.ucar.edu/~eholland/encyc6.html

Here is a simplified overview of nutrient functions:

Nitrogen is needed to build chlorophyll, amino acids, and proteins. Phosphorus is necessary for photosynthesis and other growth processes. Potassium is utilized to form sugar and starch and to activate enzymes. Magnesium also plays a role in activating enzymes and is part of chlorophyll. Calcium is used during cell growth and division and is part of the cell wall. Sulfur is part of amino acids and proteins.

Plants also require trace elements, which include boron, chlorine, copper, iron, manganese, sodium, zinc, molybdenum, nickel, cobalt, and silicon.

Copper, iron, and manganese are used in photosynthesis. Molybdenum, nickel, and cobalt are necessary for the movement of nitrogen in the plant. Boron is important for reproduction, while chlorine stimulates root growth and development. Sodium benefits the movement of water within the plant and zinc is neeeded for enzymes and used in auxins (organic plant hormones). Finally, silicon helps to build tough cell walls for better heat and drought tolerance.

http://www.sidwell.edu

You can get an idea from this how closely all the essential elements are involved in the many metabolic processes within the plant, often relying on each other.

Nutrient movement and mobility inside the plant:

Besides endocytosis, there are two major pathways inside the plant, the xylem and the phloem. When water and minerals are absorbed by plant roots, these substances must be transported up to the plant's stems and leaves for photosynthesis and further metabolic processes. This upward transport happens in the xylem. While the xylem is able to transport organic compounds, the phloem is much more adapted to do so.

The organic compounds thus originating in the leaves have to be moved throughout the plant, upwards and downwards, to where they are needed. This transport happens in the phloem. Compounds that are moving through the phloem are mostly:
Sugars as sugary saps, organic nitrogen compounds (amino acids and amides, ureides and legumes), hormones and proteins.

http://www.sirinet.net

Not all nutrient compounds are moveable within the plant.

1) N, P, K, Mg and S are considered mobile: they can move up and down the plant in both xylem and phloem.
Deficiency appears on old leaves first.

2) Ca, Fe, Zn, Mo, B, Cu, Mn are considered immobile: they only move up the plant in the xylem.
Deficiency appears on new leaves first.

http://generalhorticulture.tamu.edu

Storage organelles:

Salts and organic metabolites can be stored in storage organelles. The most important storage organelle is the vacuole, which can contribute up to 90% of the cell volume. The majority of compounds found in the vacuole are sugars, polysaccharides, organic acids and proteins though.

http://jeb.biologists.org.pdf

Translocation:

Now that the basics are explained, we can take a look at the translocation process. It should be already clear that only mobile elements can be translocated through the phloem. Immobile elements cant be translocated and are not more available to the plant for further metabolic processes and new plant growth.

Since flushing (in theory) induces a nutrient deficiency in the rootzone, the translocation process aids in the plants survival. Translocation is transportation of assimilates through the phloem from source (a net exporter of assimilate) to sink (a net importer of assimilate). Sources are mostly mature fan leaves and sinks are mostly apical meristems, lateral meristem, fruit, seed and developing leaves etc.

You can see this by the yellowing and later dying of the mature fan leaves from thesecond day on after flushing started. Developing leaves, bud leaves and calyxes don’t serve as sources, they are sinks. Changes in those plant parts are due to the deficient immobile elements which start to indicate on new growth first.

Unfortunately, several metabolic processes are unable to take place anymore since other elements needed are no longer available (the immobile ones). This includes processeswhere nitrogen and phosphorus, which have likely the most impact on taste, are involved.

For example nitrogen: usually plants use nitrogen to form plant proteins. Enzyme systems rapidly reduce nitrate-N (NO3-) to compounds that are used to build amino-nitrogen which is the basis for amino acids. Amino acids are building blocks for proteins, most of them are plant enzymes responsible for all the chemical changes important for plant growth.

Sulfur and calcium among others have major roles in production and activating of proteins, thereby decreasing nitrate within the plant. Excess nitrate within the plant may result from unbalanced nutrition rather than an excess of nitrogen.


Summary:

Preharvest flushing puts the plant(s) under serious stress. The plant has to deal with nutrient deficiencies in a very important part of its cycle. Strong changes in the amount of dissolved substances in the root-zone stress the roots, possibly to the point of direct physical damage to them. Many immobile elements are no more available for further metabolic processes. We are loosing the fan leaves and damage will show likely on new growth as well.

The grower should react in an educated way to the plant needs. Excessive, deficient or unbalanced levels should be avoided regardless the nutrient source. Nutrient levels should be gradually adjusted to the lesser needs in later flowering. Stress factors should be limited as far as possible. If that is accomplished throughout the entire life cycle, there shouldn’t be any excessive nutrient compounds in the plants tissue. It doesn’t sound likely to the author that you can correct growing errors (significant lower mobile nutrient compound levels) with preharvest flushing.

Drying and curing (when done right) on the other hand have proved (In many studies) to have a major impact on taste and flavour, by breaking down chlorophylls and converting starches into sugars. Most attributes blamed on unflushed buds may be the result of unbalanced nutrition and/or overfert and unproper drying/curing."
 
Dr. Who

Dr. Who

Well-Known Member
Venus55 said:
Another long but very interesting read:

There have been a lot of debates on this forum about flushing and there is a lot of misunderstanding about it in general flushing has its place in gardening and in the real world (other than MJ forums) is referred to as leeching.

This will be a long read but I hope it will set the record straight for everyone, this has been posted in several places here but I am putting this post together to clear things up a bit for all of you.

first a ditty from Sensi Seeds with links verifying,,,

From an administrator at Sensi Seeds

"Advanced - Flushing

A critical look at preharvest flushing

Pre harvest flushing is a controversial topic. Flushing is supposed to improve taste of the final bud by either giving only pure water, clearing solutions or extensive flushing for the last 7-14 days of flowering. While many growers claim a positive effect, others deny any positive influence or even suggest reduced yield and quality.

The theory of pre harvest flushing is to remove nutrients from the grow medium/root zone. A lack of nutrients creates a deficiency, forcing the plant to translocate and use up its internal nutrient compounds.

Nutrient fundamentals and uptake:

A good read about plant nutrition can be found here.

Until recently it was commonly thought that all nutrients are absorbed by plant roots as ions of mineral elements. However in newer studies more and more evidence emerged that additionally plant roots are capable of taking up complex organic molecules like amino acids directly thus bypassing the mineralization process.

The major nutrient uptake processes are:

1) Active transport mechanism into root hairs (the plant has to put energy in it, ATP driven) which is selective to some degree. This is one way the plant (being immobile) can adjust to the environment.

2) Passive transport (diffusion) through symplast to endodermis.

http://www.biol.sc.edu/courses/bio102/f99-3637.html

http://www.hort.wisc.edu/cran/Publications/2001 Proceedings/min_nutr.pdf

The claim only;chemically ferted plants need to be flushed should be taken with a grain of salt. Organic and synthetic ferted plants take up mineral ions alike, probably to a different degree though. Many influences play key roles in the taste and flavor of the final bud, like the nutrition balance and strength throughout the entire life cycle of the plant, the drying and curing process and other environmental conditions.

3) Active transport mechanism of organic molecules into root hairs via endocytosis.

http://acd.ucar.edu/~eholland/encyc6.html

Here is a simplified overview of nutrient functions:

Nitrogen is needed to build chlorophyll, amino acids, and proteins. Phosphorus is necessary for photosynthesis and other growth processes. Potassium is utilized to form sugar and starch and to activate enzymes. Magnesium also plays a role in activating enzymes and is part of chlorophyll. Calcium is used during cell growth and division and is part of the cell wall. Sulfur is part of amino acids and proteins.

Plants also require trace elements, which include boron, chlorine, copper, iron, manganese, sodium, zinc, molybdenum, nickel, cobalt, and silicon.

Copper, iron, and manganese are used in photosynthesis. Molybdenum, nickel, and cobalt are necessary for the movement of nitrogen in the plant. Boron is important for reproduction, while chlorine stimulates root growth and development. Sodium benefits the movement of water within the plant and zinc is neeeded for enzymes and used in auxins (organic plant hormones). Finally, silicon helps to build tough cell walls for better heat and drought tolerance.

http://www.sidwell.edu

You can get an idea from this how closely all the essential elements are involved in the many metabolic processes within the plant, often relying on each other.

Nutrient movement and mobility inside the plant:

Besides endocytosis, there are two major pathways inside the plant, the xylem and the phloem. When water and minerals are absorbed by plant roots, these substances must be transported up to the plant's stems and leaves for photosynthesis and further metabolic processes. This upward transport happens in the xylem. While the xylem is able to transport organic compounds, the phloem is much more adapted to do so.

The organic compounds thus originating in the leaves have to be moved throughout the plant, upwards and downwards, to where they are needed. This transport happens in the phloem. Compounds that are moving through the phloem are mostly:
Sugars as sugary saps, organic nitrogen compounds (amino acids and amides, ureides and legumes), hormones and proteins.

http://www.sirinet.net

Not all nutrient compounds are moveable within the plant.

1) N, P, K, Mg and S are considered mobile: they can move up and down the plant in both xylem and phloem.
Deficiency appears on old leaves first.

2) Ca, Fe, Zn, Mo, B, Cu, Mn are considered immobile: they only move up the plant in the xylem.
Deficiency appears on new leaves first.

http://generalhorticulture.tamu.edu

Storage organelles:

Salts and organic metabolites can be stored in storage organelles. The most important storage organelle is the vacuole, which can contribute up to 90% of the cell volume. The majority of compounds found in the vacuole are sugars, polysaccharides, organic acids and proteins though.

http://jeb.biologists.org.pdf

Translocation:

Now that the basics are explained, we can take a look at the translocation process. It should be already clear that only mobile elements can be translocated through the phloem. Immobile elements cant be translocated and are not more available to the plant for further metabolic processes and new plant growth.

Since flushing (in theory) induces a nutrient deficiency in the rootzone, the translocation process aids in the plants survival. Translocation is transportation of assimilates through the phloem from source (a net exporter of assimilate) to sink (a net importer of assimilate). Sources are mostly mature fan leaves and sinks are mostly apical meristems, lateral meristem, fruit, seed and developing leaves etc.

You can see this by the yellowing and later dying of the mature fan leaves from thesecond day on after flushing started. Developing leaves, bud leaves and calyxes don’t serve as sources, they are sinks. Changes in those plant parts are due to the deficient immobile elements which start to indicate on new growth first.

Unfortunately, several metabolic processes are unable to take place anymore since other elements needed are no longer available (the immobile ones). This includes processeswhere nitrogen and phosphorus, which have likely the most impact on taste, are involved.

For example nitrogen: usually plants use nitrogen to form plant proteins. Enzyme systems rapidly reduce nitrate-N (NO3-) to compounds that are used to build amino-nitrogen which is the basis for amino acids. Amino acids are building blocks for proteins, most of them are plant enzymes responsible for all the chemical changes important for plant growth.

Sulfur and calcium among others have major roles in production and activating of proteins, thereby decreasing nitrate within the plant. Excess nitrate within the plant may result from unbalanced nutrition rather than an excess of nitrogen.


Summary:

Preharvest flushing puts the plant(s) under serious stress. The plant has to deal with nutrient deficiencies in a very important part of its cycle. Strong changes in the amount of dissolved substances in the root-zone stress the roots, possibly to the point of direct physical damage to them. Many immobile elements are no more available for further metabolic processes. We are loosing the fan leaves and damage will show likely on new growth as well.

The grower should react in an educated way to the plant needs. Excessive, deficient or unbalanced levels should be avoided regardless the nutrient source. Nutrient levels should be gradually adjusted to the lesser needs in later flowering. Stress factors should be limited as far as possible. If that is accomplished throughout the entire life cycle, there shouldn’t be any excessive nutrient compounds in the plants tissue. It doesn’t sound likely to the author that you can correct growing errors (significant lower mobile nutrient compound levels) with preharvest flushing.

Drying and curing (when done right) on the other hand have proved (In many studies) to have a major impact on taste and flavour, by breaking down chlorophylls and converting starches into sugars. Most attributes blamed on unflushed buds may be the result of unbalanced nutrition and/or overfert and unproper drying/curing."
Click to expand...
Translation: Don't flush

Nice post on clearing up for many, just what is where and how it gets there....
 
nurrgle

nurrgle

Well-Known Member
There is all kinds of really good info about not flushing out there and it makes sense.

All I can say is after 20 years of growing I find my harvest tastes and burns better when I give them just water for 10 days.
 
Dr. Who

Dr. Who

Well-Known Member
nurrgle said:
There is all kinds of really good info about not flushing out there and it makes sense.

All I can say is after 20 years of growing I find my harvest tastes and burns better when I give them just water for 10 days.
Click to expand...
Bet that's still a conformation bias problem.....look that term up.... If your mind is given a task to find a difference..It will, even if there is none to find...

Proper cure, proper cure, proper cure..
 
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