-
ICMag with help from Phlizon, Landrace Warden and The Vault is running a NEW contest for Christmas! You can check it here. Prizes are: full spectrum led light, seeds & forum premium access. Come join in!
To defoliate or not?
- Thread starter Cvh
- Start date
It's a very broad term that can cover a wide range of practice from light to extreme leaf removal.
Personally i only remove leaves if they are shading a bud site or if they are getting old and fading.... my brain can't compute how removing lots of healthy leaves will increase yield, and nobody has ever given me a satisfactory scientific reason why it would.. neither have i seen a proper side by side comparison that gave better results for heavy defol.
That said, some people who do defoliate get results that are hard to argue with.
VG
Personally i only remove leaves if they are shading a bud site or if they are getting old and fading.... my brain can't compute how removing lots of healthy leaves will increase yield, and nobody has ever given me a satisfactory scientific reason why it would.. neither have i seen a proper side by side comparison that gave better results for heavy defol.
That said, some people who do defoliate get results that are hard to argue with.
VG
I too have seen threads that show how effective it can be. I have tried it in the past. For me it was more work and stress on the plants. They tend to stall for a bit then take off when they recover from it. I think it really depends on both the setup and the plant itself.
Where I really found it most effective was in pest control of mites and thrips. I would do extreme defoliation down to new growth tips and a few smaller fans. Then apply my treatments daily until eradication.
Where I really found it most effective was in pest control of mites and thrips. I would do extreme defoliation down to new growth tips and a few smaller fans. Then apply my treatments daily until eradication.
It really depends on the type of grow you have. A very dense full canopy will need to have leaves removed to facilitate air flow and light pen. I use a extreme method when I remove my fans. I want to be able to see through the plants all the way to the walls when I am done. Also some light pen to the floor helps with the light avoidance response. If you a only running a couple plants or have a lightly filled trellis then the method of just removing a few that block light to lower bud sites is more in order. Check out some of Greengenes defoil videos. He goes extreme and gets excellent results. It can be strain dependent as well. Some are going to react better than others to that type of treatment. My gg4 clone does not mind at all being stripped down round day 21. You can almost not tell after just a week or so. I think it really helps my yield and bud development down low. I have NEVER had mold, PM or Botrytis. I do live in the desert so that helps.
Have a great day all. Peace, negative.
Have a great day all. Peace, negative.
The plant evolved to have all the leaves, why remove them, it reduces the growth rate and hence yield, I only remove leaves when they die.
El Timbo
Well-known member
It evolved in an environment that most probably had resident herbivores.
Can i ask the people who DO heavy defol if they have ever tried making a proper comparison with a plant that has had less or no defol?
Just because the plant grows its leaves back doesn't necessarily mean that the practice has been beneficial...
Just because the plant grows its leaves back doesn't necessarily mean that the practice has been beneficial...
unlikely that a herbivore would carefully munch leaves without eating the bud sites and stems as well !
El Timbo
Well-known member
yes - really I was just pointing out that the plant's evolution has little to do with the discussion. The question is whether or not defoliation produces a better or more product (I don't know).
Switcher56
Comfortably numb!
This discussion has taken place before and the jury is pretty much out on the subject. I manifold/mainline all my grows now (indoors). Large fan leaves (also known as solar panels) require to be water and fed, along the way to the top(s), not unlike a kid at the end of a line getting the left overs. Mainlining when using the home water concept, of a 3/4" supply with 1/2" take offs. Pressure remains constant when a tap is opened because the main as more volume, than the take offs. That water has to go somewhere. Physics 
Ithink Paddi did some side by side grows with same genetics and defo.
From memory the yield was very similar but defo plants had tighter buds and finished a bit earlier... but not 100% sure, someone should check for his grows.
I personally defoliate to some extent, mostly for exposition and air circulation, the leaves sometimes cannot breathe properly and get wet from other leaves moisture, those i remove.
Cheers
From memory the yield was very similar but defo plants had tighter buds and finished a bit earlier... but not 100% sure, someone should check for his grows.
I personally defoliate to some extent, mostly for exposition and air circulation, the leaves sometimes cannot breathe properly and get wet from other leaves moisture, those i remove.
Cheers
This discussion has taken place before and the jury is pretty much out on the subject. I manifold/mainline all my grows now (indoors). Large fan leaves (also known as solar panels) require to be water and fed, along the way the top, not unlike a kid at the end of a line getting the left overs. Mainlining when using the home water concept, of a 3/4" supply with 1/2" take offs. Pressure remains constant when a tap is opened because the main as more volume, than the take offs. That water has to go somewhere. Physics
that takes no account of the energy that those leaves produce... by the same token the removed leaf will not be transporting sugars into the plant. Biology
It's never made much sense to me, but if someone can show a study that proves it works I will do it.
I came across a couple of interesting reads on the subject, basically saying that a lot of people do this but that there is no evidence it works. A couple of exerts from the articles and links below.
These studies below all agree that pruning of less than 25% in the vegetative stage, doesn’t cause significant yield loss. This is encouraging news for Cannabis farmers because almost across the board, it seems pretty common, especially with indoor farmers, to thin the canopy to allow increased airflow – before the end of week three.
However once you get fully into the flower stage, the detrimental effects increase rapidly.
https://cannabis-science-consulting....ation-studies/
Evidence And Conclusion:
I looked all over for any and all controlled grows, comparing defoliated plants to controls. Unfortunately i found very few. The ones i did find showed clear indications of no improvement but infact a decline in yeild. You would think that of all the people who have grown, they would have done such a simple experiment. However it seems people keep insisting on doing the method without controls and make subjective opinions on the matter. The most surprising one is where people defoliate and somehow are surprised that a few days later there is more growth. Then conclude the success of their experiment. I cannot enough make it clear how important, controlled side by side comparisons are. This is to remove any and all variables that you 'may' or 'may not' expect, regardless of what you have experienced in the past. Visial bias alone is enough to convince somone of something that is not true. Not everything is as it appears.
https://www.cocoforcannabis.com/comm...-to-defoliate/
I came across a couple of interesting reads on the subject, basically saying that a lot of people do this but that there is no evidence it works. A couple of exerts from the articles and links below.
These studies below all agree that pruning of less than 25% in the vegetative stage, doesn’t cause significant yield loss. This is encouraging news for Cannabis farmers because almost across the board, it seems pretty common, especially with indoor farmers, to thin the canopy to allow increased airflow – before the end of week three.
However once you get fully into the flower stage, the detrimental effects increase rapidly.
https://cannabis-science-consulting....ation-studies/
Evidence And Conclusion:
I looked all over for any and all controlled grows, comparing defoliated plants to controls. Unfortunately i found very few. The ones i did find showed clear indications of no improvement but infact a decline in yeild. You would think that of all the people who have grown, they would have done such a simple experiment. However it seems people keep insisting on doing the method without controls and make subjective opinions on the matter. The most surprising one is where people defoliate and somehow are surprised that a few days later there is more growth. Then conclude the success of their experiment. I cannot enough make it clear how important, controlled side by side comparisons are. This is to remove any and all variables that you 'may' or 'may not' expect, regardless of what you have experienced in the past. Visial bias alone is enough to convince somone of something that is not true. Not everything is as it appears.
https://www.cocoforcannabis.com/comm...-to-defoliate/
Last edited:
We are not growing in nature and I answered that exact question in my first post. Those statements about growth rate and yield are your opinion not facts....
I can get that there might be an argument about air flow, but not about light penetration. Why do you seem to think it is more important for direct light to hit the lower leaves tha upper leaves? What about ambient light? There seems to be this perception that only leaves that are directly getting light are adding to the plant, whereas ambient light is present below the canopy. Using the solar panel analogy, the less solar panels, the less energy. A solar panel in full or partial shade may not work as well, but it still contributes.
I often hear of people getting "excellent results" through defoliating, but nowhere do you see an actual experiment comparing clones that are defoliated to clones that are not (control). Many get excellent results by not defoliating as well.
I did experiments about 30 years ago and all the defoliated plants yielded less.
The fist link just says that a hemp plant can tolerate defoliation without significant reduction in seed yield.
the second link is just someone saying that it is good without any scientific proof.
heirloomganja
Active member
Depends on the variety you grow I think
