defoliation when in flower

Uncle Ben

Well-Known Member
Plants don't understand up, the grow towards the light source. I've don't bottom lighting and what happened was the branches all grew towards whatever light was closest to them. It was really interesting to have branches growing off the the side at the ground.
That is a hormonal response called phototropism.

Plants do indeed understand "up". That response is called gravitropism.
 

jacksthc

Well-Known Member
Means nothing except that cannabis will replenish what is lost to a limited extent. He lost yield and time due to recovery.

"Great" is a subjective term. It's not scientific and without a control group and a 3 time identical run with every factor controlled, it's meaningless.

"What if" he had left all leaves on?
The plants would have streched as the light was too high above the canopy.
without any trainning the plants would have grown tall so there would have been tall plants under a low amount of light
this would have reduce the yeild
also the plants would all be diffent height, very unlevel canopy

but will agrea the plants would have neede less time in veg
 

BobCajun

Well-Known Member
It has to do with light causing the thc to degrade faster where it has direct contact. It why lots of people say you should dry and cure in the dark and leave some fans on while hanging. Your observation is correct. And the post about leaving the bottoms a few days longer is also on point.


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One thing I noticed is that the lower buds are more resinous than upper ones, or at least more "greasy" feeling, and have less woody matter in them and are therefore milder. Tests have also shown that bottom resin is as potent as upper resin. There's no low THC resin anywhere on the plant, from the article I read anyway. It said that intense light is apparently not required to produce THC, at least not right at the bud site.
 

DrGhard

Well-Known Member
there are a couple of argument in favor of defoliating during flowering. with many caveats hoewever, and should be done cautiosly.

first of all I would like to say that the argument "leaves are the power cells of plants" etc etc etc is not 100% correct. in indoor conditions, if leaves are not reached by optimal light irradiation they actually take up more sugars than they produce. this means that the more illuminated leaves have to cater for the maintenance of the worst illuminated ones (and thus focus less on growth or bud formation). this said, defoliation in early stages of flowering should be done only in extreme cases of overcrowdness, and mostly with indica strains (they respond better to defoliation and have bigger leaves which cover up each other much more). excess defoliation at the wrong time can severly reduce your plant growth and final yield.
again, this should be done only in indoor growth, when growth light doesnt have an optimal penetration. outdoor growths have no such issue and dont need defoliation.

the second one (and more imprtant) is that stress signals or damage signals trigger a response in plant. especially the damage signals (which mimicks the damage from herbivores) from removing few leaves trigger an increased production of defence compounds. most defence compounds produced in responce to damage are secondary metabolites. and guess to which category THC and CBDs belong? :D
same goes to a certain extent when applying stress (like flushing the nutrients away for a week).
both techniques (defoliation and flushing) have the effect of increasing the production of THC and friends in the trichomes. this is hard to prove "at home" however because you cannot measure the THC/CBDs content by yourself (you can get an indication when you smoke it though hehe).

is true on the other hand that these techniques have a definite impact of growth. as such you should never defoliate or flush early in the flowering cycle, but rather towards the end of it, when buds are pretty much formed. and never exxagerate with both.
at a certain point in flowering however plants are not really investing energy into growth anymore, meaning that removing leaves will have little to no impact on bud growth, but will have a positive impact on potency.

in the end you dont really care of making 100g of less potent weed when you make maybe 95g of much more potent one through defoliation or fluching

cheers ;)

Dr Ghard
 
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BobCajun

Well-Known Member
With grapes they found that 20 leaves per bunch were optimal but cutting leaves off did not have a linear reduction in grape yield. They still got reasonable yields with 7 leaves, rather than less than half as expected. The remaining leaves became more efficient. Weird but true. You could remove half a plant's leaves and it would not make that big a difference, at least in grapes.
 

Flowki

Well-Known Member
Plants don't understand up, the grow towards the light source. I've don't bottom lighting and what happened was the branches all grew towards whatever light was closest to them. It was really interesting to have branches growing off the the side at the ground.


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I've never seen a seed do anything but roots going down and shoot going up no matter what way the seed faces. It's too much to assume this happens by accident, especially when many seeds of all kinds are germinated in darkness.

On all the vertical grows I've seen where the main or only light source was in a unnatural location the leaves did not look normal or happy above the light source. I don't know the science behind it but I guess it's the plant in a confused survival state trying to fight the countless years in evolution of gravity down / light up.
 

DrGhard

Well-Known Member
I've never seen a seed do anything but roots going down and shoot going up no matter what way the seed faces. It's too much to assume this happens by accident, especially when many seeds of all kinds are germinated in darkness.

On all the vertical grows I've seen where the main or only light source was in a unnatural location the leaves did not look normal or happy above the light source. I don't know the science behind it but I guess it's the plant trying to fight the thousands of years worth of instinct of gravity down / light up.
plants perceive gravity and light. when a plant germinates the roots grow down while the seedling grows up. the upwards growth of the seedling is just inverse gravitropism, ie the aerial part growing opposite of where the gravity stimulus (perceived in the roots) points to. the negative gravitropism of the young seedling only lasts until the chlorophyll is made and the cotyledons (the first 2 leaves) are open. at this stage phototropism takes over the aerial parts, which will grow always towards the light (even at a 90 degree angle). roots on the other hand follow gravitropism all the growth cycle.

cheers
 

kmog33

Well-Known Member
I've never seen a seed do anything but roots going down and shoot going up no matter what way the seed faces. It's too much to assume this happens by accident, especially when many seeds of all kinds are germinated in darkness.

On all the vertical grows I've seen where the main or only light source was in a unnatural location the leaves did not look normal or happy above the light source. I don't know the science behind it but I guess it's the plant in a confused survival state trying to fight the countless years in evolution of gravity down / light up.
There's a whole style of growing inverted, dunno how they start seeds, but I was talking more about foliar growth.



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Uncle Ben

Well-Known Member
There's no low THC resin anywhere on the plant, from the article I read anyway. It said that intense light is apparently not required to produce THC, at least not right at the bud site.
Best scientific data for this is Mel Frank's book.
 

Uncle Ben

Well-Known Member
With grapes they found that 20 leaves per bunch were optimal but cutting leaves off did not have a linear reduction in grape yield. They still got reasonable yields with 7 leaves, rather than less than half as expected. The remaining leaves became more efficient. Weird but true. You could remove half a plant's leaves and it would not make that big a difference, at least in grapes.
Now you're really getting into my expertise as I have a small vineyard selling premium vinifera grapes to winemakers. I've attended many a professional growers workshop and never heard anything about this leaves "become more efficient" stuff. In general, it takes 13-15 leaves per cluster to ripen a cluster properly. Here, have some.....

MouvCluster.jpg


You don't necessarily worry about balancing the cannabis crop with the canopy like you would for grapes or fruits. Your goal should be to provide the most healthy amount of root and foliage mass going into the flowering response as possible.

Uncle Ben
 

BobCajun

Well-Known Member
I think they do need a certain amount of fan leaf near a developing bud, because when I removed upper leaves and the top at 3-5 weeks they grew the first couple sets of leaves, right at the bottom of each bud, larger than normal bud leaf size. I'd say that the first 4 bud leaves grow to about the same total area as the large fan leaf that had been removed. It does then produce big solid buds though.

When plants flower, it's the leaves nearby the flowers that produce the florigen for those particular flowers. They don't spread it around the whole plant. That's probably why they replace them like that. Even though I had left large leaves at the bottom of the plant, the buds still wanted leaf right nearby, or else they wouldn't have used the energy to grow those bud leaves much larger than normal.
 
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Flowki

Well-Known Member
Your goal should be to provide the most healthy amount of root and foliage mass going into the flowering response as possible.
http://www.growweedeasy.com/marijuana-defoliation-tutorial

This man is doing the exact opposite in terms of foliage. Those plants don't look shy on top and lower bud.

Now maybe you are right and your method is superior. From the pics in that link though, can't be by much?. You are making defoliating out to be yield killing witch craft, I've seen too many grows that say otherwise.

It would be nice to see a unbiased side by side of both techniques and a dry weight.
 

jacksthc

Well-Known Member
http://www.growweedeasy.com/marijuana-defoliation-tutorial

This man is doing the exact opposite in terms of foliage. Those plants don't look shy on top and lower bud.

Now maybe you are right and your method is superior. From the pics in that link though, can't be by much?. You are making defoliating out to be yield killing witch craft, I've seen too many grows that say otherwise.

It would be nice to see a unbiased side by side of both techniques and a dry weight.
IMO is not a good example of defoliation, I defoliation all the larger fan leaves from the top of the canopy in early flower

right - Copy.JPG
 
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