To defoliate or not?

[negative37dBA]

Well seems as though you guys have all the answers without my contribution. Pretty much done with dropping any knowledge I have learned over the years....you guys got it all figured out...Enjoy. I will be just over here pulling some old fans and smoking down....keep what I have learned to myself.
I am outta here. Peace, negative.

 

[VerdantGreen]

I did experiments about 30 years ago and all the defoliated plants yielded less.

Yes, when i used to go for yields i compared notes with some decent looking defol grows, but they weren't getting getter GPW than my scrogs.

The leaves are what converts light into sugars, which is the way the plant makes energy... so by removing a leaf you are removing the plant's ability to make energy from that leaf.. and it will need to use energy and divert water and minerals from the roots to replace that leaf area. i guess the new leaf may photosynthesize more efficiently than the old leaf but i can't imagine that is enough to make up for the plant not having the leaf for a week or so and having to make another one. I apply the law of conservation of energy - that it can't be created or destroyed, just turned from one form to another... so i don't see how the process can result in extra yield.

VG

 

[f-e]

Yes, when i used to go for yields i compared notes with some decent looking defol grows, but they weren't getting getter GPW than my scrogs.

The leaves are what converts light into sugars, which is the way the plant makes energy... so by removing a leaf you are removing the plant's ability to make energy from that leaf.. and it will need to use energy and divert water and minerals from the roots to replace that leaf area. i guess the new leaf may photosynthesize more efficiently than the old leaf but i can't imagine that is enough to make up for the plant not having the leaf for a week or so and having to make another one. I apply the law of conservation of energy - that it can't be created or destroyed, just turned from one form to another... so i don't see how the process can result in extra yield.

VG

I don't think you can compare other peoples grows to your own. No matter what they do, it's unlikely you will get the same results.

It's not just about light on leaf. It's further plant training as part of the scrog. If I don't pull leaf, then the weight goes to the bigger buds which can't get the co2 so easily and are more prone to rot. Being lazy is a big chunk of the yield gone. It's my job to look at air flow and bud locations, which is moving branches and pulling leaves. Some lower stuff is nothing but a parasitic drain on the plant, if their food reserves will not be needed. In nature a plant makes these stores knowing it's depleting the land. Indoors that's not the case. Reserve leaves in the shade need supporting to stay alive. Taking not giving. Blocking the air and growing scratch. Netting/defoliation/pruning is holistic treatment.

If I get sloppy, I can kiss 20% goodbye. It's happened more times than I wish to admit. Not just one comparison, but many, in different seasons, different rooms, different systems but always using nets. This isn't even open for discussion. Only the severity of peoples efforts is of interest to me. For instance, I have no interest in illuminating the floor. For me, a leaf that covers nothing is very unlikely to be coming off. Others I have been bare a plant to nothing. Again, I will watch but won't copy. For me, it's take off the lower stuff and support what's left with uplighters. Take leaves that cover wanted bud sites. Thin out areas that are stopping airflow and avoid leaves that overlap causing actual puddles, at all costs. Lower the general canopy to get the bud lengths you want. If light needs to get through 3 leaves to light a 4th, then that's more than enough canopy depth to make use of the light. Plants are mostly light and air, so we must think about air. It's crucial yet often taken for granted.

 

[VerdantGreen]

....

I agree with almost all of what you say, and like you i train the canopy, remove leaves that are in the way, bend branches etc etc,
but removing leaves to the point where light hits the floor... i agree that can only be a waste of light imo.
This is what i meant when i said that this is a very broad term than can describe lots of degrees of defol.

i would like to see a proper side by side that displays the benefit though... the only ones ive seen or heard about result in slightly less yield for heavy defol.

VG

 

[VerdantGreen]

1.6 grams per watt... this one did ok with the leaves still on lol !

 

[Switcher56]

Well seems as though you guys have all the answers without my contribution. Pretty much done with dropping any knowledge I have learned over the years....you guys got it all figured out...Enjoy. I will be just over here pulling some old fans and smoking down....keep what I have learned to myself.
I am outta here. Peace, negative.

Whoa! Do you always take your ball and go home when folks may have a differing opinion than yours?

There has been discussion wrt it is strain/cultivar dependent, it has also been my experience as well. IMHO the bottom line is... if it is working for you and your environment, don't look a gifted horse in the mouth.

Cannabis defoliation remains a topic of heated debate among those in the cannabis industry, especially home-based growers. While some growers would never touch their cannabis plant until harvesting, there is enough science to suggest defoliation would be highly beneficial for better yields.

Ultimately, the decision to defoliate boils down to the grower’s preferences. We hope the cannabis defoliation guide above helps you achieve the best out of your cannabis garden.
https://greenrushpackaging.com/canna...wing-cannabis/

That is but one of the many links on the subject. Sad is the man that only uses 1 source of information...

 

[Devoted2rolling]

A happy medium would be to grow normal healthy cannabis instead of a leafy clusterfuck of NPK.



I know how many leaves every plant in my room has. Tell me how many nodes/weeks I'll tell you how many leaves it had. Why would I grow leaves just to remove them. But you know, 99.9% of the people on this site do not know the purpose of photosynthesis.

 

[@hempy]

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.

Less bud means less seed no loss in seed means no loss in yield.

Second link is research conducted on hemp. In 2018 and 2019, an experiment was conducted to simulate insect defoliation on grain variety hemp plants

to determine whether a loss of foliar area could impact yield. This experiment was
conducted at Virginia Tech’s Kentland Research Farm in Whitethorne, VA. Hemp plants were manually defoliated with
shears to remove varying levels of leaf material from plants at varying times throughout the season. Plants were defoliated.

The third link has the best info.

It is backed by scientific research that shows that older plant leaves do not contribute as much to plant growth as new, smaller leaves, but instead, they become detrimental.

According to research, as plants grow, so does the size of their leaves. Older leaves become larger, thereby taking up even more water, sunlight and other nutrients even though their ability to support photosynthesis and other necessary processes is more limited. Defoliation aims to eliminate these older leaves and rejuvenate the cannabis plant.

Defoliation has been proven to boost the yields you can get from your cannabis garden. There are two angles to this: the first revolves around the plant hormone ethylene, which is known to lower yields because of its ability to trigger aging processes within plant cells.

Per nature’s design, ethylene is found in higher concentrations in older leaves and flowers, such as those at the lower ends of the cannabis plant. Defoliation effectively nips these leaves and flowers, triggering higher yields for the plant.

The second angle revolves around defoliation’s ability to increase the exposure of leaves to sunlight and air, which directly stimulates more photosynthesis, better growth and larger yields by harvest time.

 

[Amynamous]

I will defoliate when i go on vacation to reduce transpiration and water usage when i am gone.
I hate coming home to crispy plants.

 

[Gry]

Generally worked out well for me.
Can't help but wonder to what extent it may be strain dependant.

 

[Hammerhead]

Plants with super dense structures might benefit the most. IMO defoliation and pruning are not the same. If all the leaves are removed it makes it impossible to diagnose plant issues.,

 

[Switcher56]

Generally worked out well for me.
Can't help but wonder to what extent it may be strain dependant.

If you maintain grow logs, you can see this. Hybrids and Indicas benefit the most, not so much so with Sats. In my experience, Bd and Pk didn't like it. Then again, those two could be blamed on genetics.

FWIW, I got rid of my solar panels (current run Rg and KL XIII) roughly 6" across, 3 days later the leaf below the (future flower cluster (e.g the 1st leaf to receive both nutes and water)) was 4".

Solar panels do indeed provide greater photosynthesis, they also eat and drink a lot more as well. My theory (supported by others) the extra sugars produced during photosynthesis, gets stored in the roots. Therefore, you get rid of those hungry buggers (after they have done their job) and they are no longer the dominant dog that finishes his bowl and proceeds to eat the rest of them, who merely get/got scraps vs a proper feeding.

 

[@hempy]

I would have to disagree with that Switcher56 Sativas and sative hybrids benefit the most from defoliation and indicas the least.

I still do it on indicas but its more to open up the plant to allow better air movement to reduce the risk of problems.

 

[Switcher56]

I would have to disagree with that Switcher56 Sativas and sative hybrids benefit the most from defoliation and indicas the least.

I still do it on indicas but its more to open up the plant to allow better air movement to reduce the risk of problems.

Agree, but... I have never been a proponent that defoliation increases yield. I simply use it because it suits me in how I grow in my environment and growing conditions (period)

TBS, IME, it doesn't slow the plants down as some folks would like to claim. Nothing more, nothing less. I am not here to compete with anyone else. I am simply reporting my experience with manifolding, which in itself, is a pretty drastic technique.

In my limited experience, I may have prematurely stated that Sativas don't benefit from defoliation as I don't grow sativas perse. I am/was simply stating that the strain/cultivar that didn't "benefit" from "manifolding" was indeed sativas. My best run was Nl and La Conf @ 1.2g/w. I simply stated the end result. TBS, it is to be noted, that it could very well be attributed to genetics (which I have previously mentioned as well)!

My worst run... without "the benefit" of defoliation (after topping), came in @ 0.7g/w, which was comprised of Bd and Dt... Bd being the culprit (brought the avg down). I didn't expect it/that.

Having previously grown Dt, with simple topping, based on "my" data e.g nothing else changed, led me to the culprit, being Bd. I can come to the conclusion wrt to Bd as being piss poor genetics, as it took me 4 beans to get 2 plants, which I have never experienced in the past. As many, I do have the "odd" bean that don't sprout, "odd" being the operative word here. I will repeat the "experiment" with seeds from a different breeder.

My current run was supposed to be Rg, Ht and Kl (all from the same breeder/seed bank). Ht (harle tsu) failed 3 times. They sprouted tails but refused to germ. I have 2 beans left. I doubt the remaining 2 will amount to anything, as both Rg and Kl did their job per usual.

I keep judicious notes, and learn from each run on areas to improve. What I don't do, is go "helter skelter" on lessons learned e.g throwing the kitchen sink at things. I will modify 1 thing, 2 at best, and extrapolate the results, with the analogy that... Too many cook spoil the broth. e.g what worked and what didn't.

 

[@hempy]

You can stall a plants growth if you over do it and fully strip the plant. The plant will stop and re focus its energy on re producing leaf but that's not the idea of opening up the plant to allow more light on more sites.

This is the type of results i get.

This plant is a 50% haze hybrid on one side of a 600Hps 2 plants under that light.

 

[Switcher56]

Lovely girls
What did they yield and how tall were they?

 

[HempKat]

Well you opened the typical can of worms that gets opened when this question gets put out there and as you can see there are very strong opinions on either side. My personal opinion would probably most align with Switcher56. Which is that thoughtful leaf removal can be beneficial but there are many variables that come into play. A lot of justification comes down to light penetration and in a grow room with one or a few lights overhead that makes sense due to things like inverse squared and how that plays out with the strength bulb you use and how tall you let the plants get. On the other hand what about a grow that employs both overhead lighting and lower side lighting? I've never done that myself but it would seem that sort of light set up could handle more leaves and taller plants. Then also what about outdoors where the light hitting the bottom of the plant is more or less the same strength as what hits the top since the light has already travelled so far a few feet won't make much difference.

Then there's other more personal preferences some people like to grow a cola on a stick and for them a bunch of lower growth is anathema but someone growing a more traditional plant secondary and even tertiary buds are acceptable and they would likely be more open to spreading the plant apart more without removing a bunch of leaves. Still no matter where you grow or how you grow or what light you use there's always going to be some defoliating going on if by no one else then by the plant itself. It's been my observation that as growth becomes more of a drain then it is a benefit to the plant, the plant will gradually work that growth out of the equation but it can be somewhat slow about it if overall good plant health is maintained. In those cases I see nothing wrong with helping the plant speed up the removal process a bit.

 

[@hempy]

I normally veg from seed for 4 weeks under a HPS then put them in flower the 50% Haze take around 4 to 5 weeks to start to flower. I just veg all to a set high and put in flower.

Yield can very but the plant above trimmed and cured and no steam yielded just over 14 oz.

Different 50% Haze

Thai sativa

I follow the belief that every one dose things different their is no right or wrong way of doing things. What counts is you are happy with the results you get.

You do what works for you but my problem lies with people that claim something dose not work when they them self's have not ever tried it.

 

[@hempy]

Here are 2 more plants that makes 5 completely different plants

SSH

MH

Flower of this MH

I have been doing this for a very very long time out doors and in.

No matter what side of the fence you sit on in this debate what counts is you are happy with your results.

 

[Switcher56]

Well done! Thank you

No matter what side of the fence you sit on in this debate what counts is you are happy with your results.

That's a fact Jack