Scientific evidence for selective DEFOLIATION

Look at this AWESOME free text I found online, anyone who is serious about growing should read it, maybe it will stop all this 2nd grade regurgitated information about what leaves do, yes we all leaned about photosynthesis.

Bottom llne is if your not removing SOME fan leaves strategically, and your growing indoors, your not maximizing your space or yield.

Here is the text, it's free

http://plantsinaction.science.uq.edu.au/edition1/?q=content/home-page

It's called ADAPTATION IN NATURE AND PERFORMANCE IN CULTIVATION

I read the entire thing. Turns out leaves are REALLY important...some are more important then others. Some, like the really big large fan leaves actually compete for energy with your buds. Hey I'm not a scientist, but the people who wrote this book all are.

Those really big fan leaves everyone says are big storage units that directly influence the size of budz...well they aren't, they are competitors.

I know from my personal experiences on EVERY strain I ever grew, that removing these big fan leaves(when you need to for room/air movement/light penetration to lower branches) during veg(the ones at the base of a branch where it meets the stem) caused a growth spurt in the branch it was cut off of.

Here's proof!

"
Distribution patterns of 14C-labelled products relate to developmental morphology of fruiting shoots. Typically source leaves are nearby on the same lateral branch, both above and below the fruit. In apple, fruiting spurs may develop primary leaves (emerging soon after budburst), then spur leaves (in a rosette at the base of the flower), then bourse leaves (growing on spur bourse shoots). Each in turn provides assimilate for the next phase of leaf growth (primary → spur → bourse); then as leaf expansion ceases, all provide assimilate to the developing fruit (Tustin et al. 1992). Leaves on adjacent extension shoots can provide some photosynthate to fruit, but if indeterminate growth continues furthermost leaves become progressively less important as suppliers, and more significant as competitors. If the normal suppliers are removed, carbohydrate can come from longer distances, sometimes from leaves more than a metre away (Bollard 1970).

Relative strength of source and sink is a major factor for distribution patterns, but transport options are dictated by vascular connections. During plant growth, development occurs in an orderly and patterned manner, creating separate files of leaves. This pattern (phyllotaxis) is accompanied by a matching pattern of vascular connections. Photosynthate tends to move along a pathway of least resistance, following these direct vascular connections where they exist, hence distribution patterns generally follow phyllotaxis."

So there you have it, leaving all your fan leaves on while your growing indoors is taking energy away from your buds. The plant needs energy to support those big ass fan leaves.

In fact those big fan leaves are only suppliers when they are about 50-70% their final size, once they reach any bigger they are no longer the plants main source for energy, quite the opposite. They were made to produce energy for the new branch, once the branch is developed, it actually takes energy away from the bud at the top of it-it competes for food and the food reaches the that fan leaf first.

Read the damn book, think critically, and stop listening to people on cannabis forums-we're a bunch of sheep who listen to hobbists over scientists. Do your own research, the information is out there and it has been out there for a while.

I tried to leave all my leaves on my plant before, I got leafy larf bud towards the bottom of my plant and big beautiful fan leaves all over the place.

I am NOT talking about defoliation! I am talking about selectively pruning and manicuring your plant-those people who grow the darkest red roses know what their doing, and they know which leaves to remove to accomplish this.


In nature, the leaves serve a FAR greater purpose then turning light into energy. They are big resin coated pollin catchers. Plants don't want to grow big buds, they want to become fertilized as soon as possible and put their energy into making seeds.

I want nice fat buds in a nice even canopy, I don't see how this is possible without removing some of these leaves.

It seams the people who are against removing leaves grow huge trees-no wonder they are happy with their yeild!

This was important part, i forgot to make it bold!

"but if indeterminate growth continues furthermost leaves become progressively less important as suppliers, and more significant as competitors"

Please don't be hostile regarding this info.

I'm not talking about defoliation, but after years of trying different techniques, selective pruning and manicuring during veg is the real way to maximize your space/yeild. After you do it long enough you see how different techniques effect the plant. Removing cetain leaves has been more beneficial then leaving them all on.

I think we all forget that cannabis doesn't want to grow big fat buds, it want's to get pollinated as quick as possible and divert all it's energy into making seeds.

All those big fan leaves act as sticky pollin collectors, this is why they take energy away from branches/bud sites after they reach 60-90% of their final size, the plant would rather put energy into creating a large surface to collect pollin-remember it wants to get pollinated, not grow big buds. The fan leaves aren't there to help grow big buds, they are first formed to send energy into making a new branch, once the branch is formed and they reach 60-90% their final size, they compete for energy with they branch they helped create. Every leaf gets less important the closer you get to the stem.

It's all there in the text. I don't want to start an argument, but this is science...something I find extremely lacking in these forums.

Section referenced, for the lazy:

http://plantsinaction.science.uq.edu.au/edition1/?q=content/11-3-2-photoassimilate-distribution

Props for doing the due diligence that keeps the community moving forward!

Key word is SELECTIVE.

My rule of thumb is if 1 leaf blocks 4 then off it comes.

Thanks monoss.

The people who say that if you remove fan leaves then, "you don't know basic biology" really mean, "I only know basic biology and photosynthesis is how plants make energy". More accurately, they don't fully understand plant biology.

I read the entire book, and I contiune to research on a daily basis.

I'm trying to find a reference to the hormone that is released after an animal grazes on the plant, which can result in hyper vigor. This is demonstrated on certain grasses that animals graze on, and on other low hanging vegatation that is often eating by animals.

I LST and tuck everything I can, as long as I can. If a big fan leaf is shading a big area of my plant, or a lower branch, removing this(during veg) and letting light hit that lower branch causes it to shoot up to the top.

I'll take another, developed, budsite over a big fan leaf anyday. It's hard to develop these if your not diligent about training and selective leaf removal, at least in my experience.

frankly any form of training, when done right, results a good return.

Me personally, I like to super crop and remove big fans during veg.

It simply amazes me every time I see how a plant regenerates its strength where a crimp was placed to super crop the plant.

Generally the parts of the plant that were crimped come back 1-2 times thicker then it originally was and all the post supercrop shoots become big players.

It sure would be nice to see this type of testing done on actual marijuana plants.

Examples of defoliation, I like the concept.

I pull all fan leaves off the main stock as they come out almost. Then 1 week before i chop i pull all the rest. It works very well for me.

This is why I leave mine alone to grow naturally. Got nugs at the bottoms of 4-5 feet tall plants.

One piece of scientific research really isn't going to end this debate. There's plenty of research that shows negative effects for other species.

Nice try though

Proper plant and budsite spacing will get you max yields faster than removing leaves will.

Elite Nugz said:

This is why I leave mine alone to grow naturally. Got nugs at the bottoms of 4-5 feet tall plants.

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Same here, I pack my plants and crop them very tightly, and get about a gram of popcorn from 6 plants. Tried a few myths and forum methods to reduce fluff/popcorn, who would have thought it turns out the trick was simply to let them do their thing.

Sativied said:

One piece of scientific research really isn't going to end this debate. There's plenty of research that shows negative effects for other species.

Nice try though

Proper plant and budsite spacing will get you max yields faster than removing leaves will.

Same here, I pack my plants and crop them very tightly, and get about a gram of popcorn from 6 plants. Tried a few myths and forum methods to reduce fluff/popcorn, who would have thought it turns out the trick was simply to let them do their thing.

Click to expand...

I totally agree. Proper plant and branch spacing is all thats needed. Get that right, and there's no need to remove leaves.

The university study is cool and all, but it wasnt done on marijuana, so there's still a lot of room for debate here.

Statements like,

"My rule of thumb is if 1 leaf blocks 4 then off it comes. "

Are puzzling to me.

Outdoors, the sun tracks an arc across the sky,
The planet spins
So, the shading moves accordingly.

And the wind blows, and the leaves move, and the stalks and trunks sway, and everything gets some sunlight.

Indoors, unless you have a light mover, you need fans for more than ventilation and odor control.

We use oscillating fans to strengthen the stalks and move the leaves around.
I use the single cooling fan on my LED panel to torque the array and keep the shadows moving.
Nothing gets "shaded" for long.

I'm not debating selective defoliation here, yet.
Have not read the text yet.
I'm just wondering about the logic of doing it for shading purposes.


Aloha,
Weeze

Thanks for your research.

Thanks for your research.

Squidbilly;6308704 I'm trying to find a reference to the hormone that is released after an animal grazes on the plant said:

Not sure if you read this one but this was one of the main facts that kept me fiddling with defoliation.
The Jasmonate Signal Pathway
http://www.plantcell.org/content/14/suppl_1/S153.full

Small introductory quote from the study
"
Plant responses to many biotic and abiotic stresses are orchestrated locally and systemically by signaling molecules known as the jasmonates (JAs). JAs also regulate such diverse processes as pollen maturation and wound responses in Arabidopsis. Here we review recent advances in our understanding of how JA biosynthesis is regulated, the signaling functions of different JAs, and how the JA signal may be transduced via an E3 ubiquitin ligase. We also examine how outputs from the JA, salicylic acid (SA), and ethylene signal pathways are integrated in the regulation of stress response and plant development.
We use the term jasmonate to include the biologically active intermediates in the pathway for jasmonic acid biosynthesis, as well as the biologically active derivatives of jasmonic acid. These compounds are widely distributed in plants and affect a variety of processes (Creelman and Mullet, 1997), including fruit ripening, production of viable pollen, root growth, tendril coiling, plant response to wounding and abiotic stress, and defenses against insects and pathogens."

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I have no evidence but I am convinced trimming plant growth promotes more prominent re growth.

The real consideration to think about IMO is bud density and how to manipulate it. I am not sure if training and all that promotes more flowers but it for sure promotes more dense nugs where the light meets the plant...which then translate to faster trim times, less nonesense lower growth, and a prettier cola nug.

When I get heavy transporation between leafs when they are resting on one another, I know it is time for a manicure.

I dont know what you call the concept but it is seen through out nature. Most of the time when something is cut, it comes back more robust. Thats why some chicks trim their eye lashes...they believe it makes them grow back longer, when we cut back dormant grass, it comes back greener, when tree limps are removed, twice the amount in new limbs appear.

Now whether or not any of this means stronger and heavier fruition and end result....why I think that is the topic for heavy debate.

But for my self...I am 110% convinced defoilation and training of any kind is done to manipulate the plant and to utilize the available light, which then can led to better yields. I suppose you are not destroying energy when trimming, but mearly directing it where to be utilized and how to utilize that energy to its fullest potential

Super crop a limb, it is amazing how big, strong and rock hard the re growth comes back as and then their is huge room for debate.

Someone should start a photo thread for trained plants of any kind. We have everything else on here.

My buddy ran a 4x8 table with three 600 watters over them. He was running Gods Gift, which is a big leafed Indica dom plant. He lightly defoliated one half of his table. That table ended up with a few hermie male flowers here and there and the yield was less on the defoliation side. Plants looked weak and battered, buts were more fluffy... but the side he didnt touch was healthy and vibrant.

Its the only non-bias test that I've seen a personal friend do. I wouldnt even give it a shot, but he took the dive... So just from my personal experience.. I stay away from it.

I do have buddies that strips the leaves down in the last two weeks of flowering.... but I find seeds in his buds quite a bit.

Id definitely like to see some more side by side comparisons though. From people who arent trying to prove or disprove defoliation. Id do it myself, but Im not willing to kill my yields or potentially seed my crop.

Elite Nugz said:

My buddy ran a 4x8 table with three 600 watters over them. He was running Gods Gift, which is a big leafed Indica dom plant. He lightly defoliated one half of his table. That table ended up with a few hermie male flowers here and there and the yield was less on the defoliation side. Plants looked weak and battered, buts were more fluffy... but the side he didnt touch was healthy and vibrant.

Its the only non-bias test that I've seen a personal friend do. I wouldnt even give it a shot, but he took the dive... So just from my personal experience.. I stay away from it.

I do have buddies that strips the leaves down in the last two weeks of flowering.... but I find seeds in his buds quite a bit.

Id definitely like to see some more side by side comparisons though. From people who arent trying to prove or disprove defoliation. Id do it myself, but Im not willing to kill my yields or potentially seed my crop.

Click to expand...

I don't have any comparison but I can post pics of my veg plants because I just gave them all a heavy manicure 2 days ago.