Leaf trimming
- Thread starter rcory69
- Start date
Yes, just remember the leaves are the most important part of the plant, it allows the plant to take light and produce energy (need this energy to produce big buds) . Imo each leaf trimmed off needs to be evaluated on what it is opening up. That one big fan leaves can produce a lot of energy, so if you cut it then you are losing that energy producer, if it opens up many smaller leaves and bud sites then it might be beneficial to cut the one leaf to give light to many. This could increase the amount of energy the plant can produce. I'm a big fan of less is more when talking about trimming during flower, for me it's more of a open up air flow, and getting rid of leaves and bud sites that are not in the light and not able to produce energy (lollipopping). But allowing light penetration is beneficial if done correctly.
Thanks figured I would check it out.
One of the principals over at cocoforcannabis (PhD in one of the ag disciplines) brought up a few interesting points about defoliating (vs pruning).
First issue was that removing a leaf at, for example, the canopy so as to allow a leaf that's 6" lower means that you're losing a good amount of photons because there's so much of a PPFD drop in even that short a distance. That's absolutely true. I use an Apogee and just changing the location by a few inches can see a loss of 100µmol.
A second point is that primary purpose of the leaves in the canopy is receive incoming photons and process them via photosynthesis. Leaves that are below the canopy do not have that as their primary function and are not as well suited to do that. He claims that exposing leaves in the canopy can actually lead to damaging those leaves. I've never thought of that and it's an interesting point.
One justification for removing leaves is to "expose bud sites" but I have no idea why that's needed. Bud sites are (future) flower buds and have a very different structure than leaves that are designed to photosynthesize. That trade off just didn't make sense to me.
What I have found interesting is that across the spectrum (pardon the pun) of researchers and consultants with a background in plant biology uniformly agree that we should prune and defoliate plants to remove damaged foliage, to ensure that there's adequate air flow, and to be proactive in terms of reducing the chances of disease. Other than that, there's agreement that there's no justification for removing healthy plant material.
It's interesting that cannabis conventional wisdom "leans heavily", to say the least, toward defoliation, some g torowers remove a staggering amount of leaves, while the pointed headed guys, whose reputations and livelihoods depend on the outcome of their pronouncements, look at the issue so differently.
My practice? I remove leaves from below the canopy only for airflow in almost all cases or to remove fan leaves that are obviously heavily senesced and ready to drop. However, I do remove small stems and immature buds simply because cannabis generates so much flower that I don't want to have to muck with the ash and trash when it comes to harvest.
If anyone has found any research on this, I'd appreciate you sharing a link.
First issue was that removing a leaf at, for example, the canopy so as to allow a leaf that's 6" lower means that you're losing a good amount of photons because there's so much of a PPFD drop in even that short a distance. That's absolutely true. I use an Apogee and just changing the location by a few inches can see a loss of 100µmol.
A second point is that primary purpose of the leaves in the canopy is receive incoming photons and process them via photosynthesis. Leaves that are below the canopy do not have that as their primary function and are not as well suited to do that. He claims that exposing leaves in the canopy can actually lead to damaging those leaves. I've never thought of that and it's an interesting point.
One justification for removing leaves is to "expose bud sites" but I have no idea why that's needed. Bud sites are (future) flower buds and have a very different structure than leaves that are designed to photosynthesize. That trade off just didn't make sense to me.
What I have found interesting is that across the spectrum (pardon the pun) of researchers and consultants with a background in plant biology uniformly agree that we should prune and defoliate plants to remove damaged foliage, to ensure that there's adequate air flow, and to be proactive in terms of reducing the chances of disease. Other than that, there's agreement that there's no justification for removing healthy plant material.
It's interesting that cannabis conventional wisdom "leans heavily", to say the least, toward defoliation, some g torowers remove a staggering amount of leaves, while the pointed headed guys, whose reputations and livelihoods depend on the outcome of their pronouncements, look at the issue so differently.
My practice? I remove leaves from below the canopy only for airflow in almost all cases or to remove fan leaves that are obviously heavily senesced and ready to drop. However, I do remove small stems and immature buds simply because cannabis generates so much flower that I don't want to have to muck with the ash and trash when it comes to harvest.
If anyone has found any research on this, I'd appreciate you sharing a link.
Star Dog
Well-Known Member
If I could point out a few roles of leafs that might get overlooked.
The obvious one, the collection of light it's the foundation of growth, leafs make food for growth via light.
They absorb co2 a vital building block for growth as we all know.
Transpiration, removing leafs kills transpiration as the surface area has been removed.
Transpiration...
the amount of nutrient getting taken up is reduced for obvious reason.
They store starch/food that's responsible for feeding plants in the dark period,
a iodine and starch test confirms this, it's set in stone.
If you do a iodine starch test before and after lights on you get very different results, before light the leafs stays white because there's no starch available for the iodine to bond to, after light on the leaf turns black because iodine is bonding with starch the plant has made through photosynthesis.
(Science based fact)
The obvious one, the collection of light it's the foundation of growth, leafs make food for growth via light.
They absorb co2 a vital building block for growth as we all know.
Transpiration, removing leafs kills transpiration as the surface area has been removed.
Transpiration...
the amount of nutrient getting taken up is reduced for obvious reason.
They store starch/food that's responsible for feeding plants in the dark period,
a iodine and starch test confirms this, it's set in stone.
If you do a iodine starch test before and after lights on you get very different results, before light the leafs stays white because there's no starch available for the iodine to bond to, after light on the leaf turns black because iodine is bonding with starch the plant has made through photosynthesis.
(Science based fact)
rcory69
Member
Thank you for the info. I don't remember how I found this site but I've learned alot reading and chatting with folks on here
EmeraldGreenGal
Member
Thanks so much for all the info in this thread! I was about to ask the same question but search function to the rescue!
Star Dog
Well-Known Member
I use these little pouches for convenience I really like them.
I keep mother's and potential mothers in them from each crop and even prep plants to flower with them.
Naturally I see there root growth every day and without a doubt each time I defoliate (purposely to slow growth on stock plants) I see the root growth slow quite considerably, it had been brought to my attention previously but I'll not go into that.
On the upside to defoliation it can be a saviour if you're humidity is out of control it does lower rh% through less transpiration in the area.
I started to defoliate if it's required after flipping to limit stretch, I'm robing the plant of the ability to grow is my logic and it appears to work?
The plants at the back were more sativa leaning and the ones at the front more indica leaning, I defoliated the back and left the front.
It finished pretty even all considered.
I keep mother's and potential mothers in them from each crop and even prep plants to flower with them.
Naturally I see there root growth every day and without a doubt each time I defoliate (purposely to slow growth on stock plants) I see the root growth slow quite considerably, it had been brought to my attention previously but I'll not go into that.
On the upside to defoliation it can be a saviour if you're humidity is out of control it does lower rh% through less transpiration in the area.
I started to defoliate if it's required after flipping to limit stretch, I'm robing the plant of the ability to grow is my logic and it appears to work?
The plants at the back were more sativa leaning and the ones at the front more indica leaning, I defoliated the back and left the front.
It finished pretty even all considered.
Fatjoe
Well-Known Member
Your dead on. Good description of common sense leaf removal. I might add we need those leaves not just for the plant but for us as well. The leaf is the first warning sign for most everything that can go wrong.
amneziaHaze
Well-Known Member
dont be one of those guys that cuts all fan leafs.plan is to have soo much leafs you dont see lamps direct light on the floor
Fatjoe
Well-Known Member
@pilted I like the way you think. You had me at..less is more...Welcome aboard.
@Star Dog You lay out info so I can understand it better. Thanks. I seem to always have a small pile of leaf outside my tent when I'm done for the day. Like your example of there's a time and place for removing leaf. Ya just use common sense.
@Delps8 thanks for all that info. Your another one who makes it easy to understand. Lots of valid points in all that. I read all I can find on this stuff and I'm hands on with my plants daily. Use a lot of training with screens. I have no choice but to remove leaf..lol
I kinda look at it like this. No way I'll ever match that sun outside. Being indoors I can setup my environment perfectly but can't match that big star. To me somethings gotta give to get the most light I can get penetrating my canopy...leaf.
@rcory69 Welcome to Riu. Thanks for starting this thread. It sparked some great info being shared.
@Star Dog You lay out info so I can understand it better. Thanks. I seem to always have a small pile of leaf outside my tent when I'm done for the day. Like your example of there's a time and place for removing leaf. Ya just use common sense.
@Delps8 thanks for all that info. Your another one who makes it easy to understand. Lots of valid points in all that. I read all I can find on this stuff and I'm hands on with my plants daily. Use a lot of training with screens. I have no choice but to remove leaf..lol
I kinda look at it like this. No way I'll ever match that sun outside. Being indoors I can setup my environment perfectly but can't match that big star. To me somethings gotta give to get the most light I can get penetrating my canopy...leaf.
@rcory69 Welcome to Riu. Thanks for starting this thread. It sparked some great info being shared.
Fatjoe
Well-Known Member
That shit makes me just cringe..lol I call them Charlie Brown trims