FAN LEAVES - To trim or not to trim, that is the question

CelticCannabis · Sep 29, 2020

When I decide to post a question to THC, It’s usually after researching internet articles to get as much information as I can. In general, it seems to leave me confused due to the myriad of opinions and articles.

So my questions are about trimming fan leaves. Is it “best practice” to trim fan leaves? Is it best practice for indoor hydroponics growing versus outdoor? If this is a best practice, when should it be done during the growth cycle? Is the trimming of fan leaves repeated? What are the positive benefits? Are there negatives to trimming fan leaves?

I chose to post these questions in the Indoor Hydro section because this is my preferred method of growing. I realize there may be varying opinions but I welcome all.

growsince79 · Sep 29, 2020

It depends on strain and growing techniques. If you keep them small and not overcrowded, you probably only need to remove bottom leaves. If you try to cram 4 trees into a closet, you might have no choice but to defoliate. Outdoors is almost never needed.

Grownsince95 · Sep 29, 2020

For me its a question of "are they pulling their weight?" If they're in full light not blocking another important bud site they stay...freeloaders on the bottom of the plant in shade are only surviving because of the work done by the top leaves so they gotta go. I want those resources put where they count.
Think if them like solar panels for the roots...you would only place them in the most efficient places. Just my .02

mysticepipedon · Sep 29, 2020

I think defoliating is not so important outside, unless your garden has poor air circulation and is humid.

Defoliating is important indoors for, at the very least, air circulation. Also, lower plant parts receive much less light than upper plant parts indoors (not the case outdoors, unless the lower parts are shaded).

It seems like commercial operations do it quite a bit, which leads me to think there is more benefit than just air circulation. But I have never seen any kind of side-by-side comparisons of defoliated vs. non-defoliated grows.

JWM2 · Sep 29, 2020

I’ve seen it with my own eyes bud sites that are shaded don’t fully develop as well as those that are in direct light.

In fact I just recently ran across an article on Leafly talking about the misconceptions of outdoor growing. One of the misconceptions was quality due to the fact that 20 years ago most had to hide their crops from local authorities and therefore preferred areas with lots of shade. The shade then made the plants produce mostly undeveloped buds which translated into the misnomer that outdoor buds taste and smoke like “homegrown” or low quality material.

While I cannot attest to this theory it does make sense and as stated before I’ve seen the difference myself and practice defoliating as a way of maximizing my harvest and yield.

Madmax · Sep 29, 2020

Never had to defoliate outdoor as i plant in open with full sun.i live in an illegal state so to maximize the plant i lst and give ea branch there own space they grow in.lsting keeps them low for stealth..ive been taught never pull them off....plants really sort themselves out outdoors and create there own space.i do however take small growth of stems down in the guts and sucker branches that dont eventuate into anything.i dont have to pull them off but i do as i wish..

Grownsince95 · Sep 29, 2020

I think another important point about defoliating is that it's a high stress technique that should only be employed on very healthy plants. Remember that plants store their excess nutrients in older fan leaves and will call on them for mobile nutrient deficiencies. Without them you are leaving your more prime sites susceptible to any stress by removing the reserves. So have all your ducks in a row first and start slowly to see how your particular plants respond.

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Grownsince95 · Sep 29, 2020

And anyone who says it's not a "natural " part of the plants life cycle has obviously never had deer in their yard!

I suspect any increased resin production due to stress is an attempt by the plant to make itself less desirable. Also hahaha!

Madmax · Sep 29, 2020

Uno i do believe certain species of plants release a certain toxin after they have been nibbled on by some herbivore.would have built up some form of resistance over the thousands of years they have been around.

CelticCannabis · Oct 1, 2020

Grownsince95 said:
I think another important point about defoliating is that it's a high stress technique that should only be employed on very healthy plants. Remember that plants store their excess nutrients in older fan leaves and will call on them for mobile nutrient deficiencies. Without them you are leaving your more prime sites susceptible to any stress by removing the reserves. So have all your ducks in a row first and start slowly to see how your particular plants respond.

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Interesting. Thank you.

nashobaTHC · Oct 1, 2020

I really wish that a grower in a legal state that has maximum sunlight in the grow area could do a side by side grow of regular bud growth and defoliated bud growth to give good comparison of bud growth. Based on my years of internet searches on this subject, it seems like 60% favor keeping leaves on and 40% day defoliate.

Milson · Oct 1, 2020

I have been defoliating on this grow and have really liked the way the plants have responded. Only do it on super vigorous plants of course but I have found the lower branches coming up to fill the gap very well in my branchy girls. The more hash plant structures? Yeah way less point.

The plant will tell you if it's okay to pull the fan by how easily it comes off when you use your fingers. Again, this is just my opinion. I never take them off the very top because I think the plant is using that energy more broadly and would like to keep it. The stems would never allow it.

This is all indoor btw.

GNick55 · Oct 1, 2020

better learn about trichomes before cutting off your fan leaves, yes at first the clear trichomes act as a kinda “sunblock” but as they turn milky, the sunblock affect is not so good and light and heat will start to degrade the thc in the trichomes causes them to turn amber.. then fan leaves keep her healthy as she can feed from them when needed and the bit of shade helps too., it’s really all about the Trichomes!!

MIMedGrower · Oct 1, 2020

What an excellent discussion on defoliation. :-)

I still think there are many variables. I keep space around my plants and dont like leaves touching so i rarely pull a leaf unless the plant is super bushy and like said above seems like some lowers are not developing properly.

Other than that i have seen huge buds growing under massive fan leaves many would feel are in the way.

But when a room is crowded with many overlapping leaves there are many reasons picking off leaves will help. Mostly airflow and reduced stale humid pockets and some light advantage.

Right tools and techniques for the job at hand.

Porky1982 · Oct 1, 2020

Years ago when I grew outside I got some cuttings of a mate and was curious about a heavy defol vs a medium vs not at all.
I found that a very heavily defoliated plant by this I mean basically stripping most of the fully grown leaves up to 4 weeks from finish yielded only slightly less that the other 2 which were basically the same.
I did however notice that the plants that were left with minimal to no defol had attracted more bugs as they had much more leaf area for them to eat and need more pest management.
I grow inside only now because I live in suburbia and can’t grow outside but I don’t really bother with defol unless I think airflow is being impeded.

OldManRiver · Oct 2, 2020

Defoliation outdoors is unnecessary, and counterproductive. Those leaves help the plant make more bud, and by trimming them, you're reducing the energy available to make flowers. I just clear out weak interior buds, and clear dying leaves as they happen. The plant knows when to drop the leaves. This time of year, that plant wants to make flowers/seeds, and is better equipped to figure what to do with it's leaves than I am. By the end of the season, the interior leaves are yellowing, and I pull them for air flow. The yellowing indicates that the plant has pretty much sucked the leaf dry for energy, and it won't hurt to pull it then.

MHOGSMI · Oct 2, 2020

Shawazzie technique.
I strip my ladies 3 times.... Week before flip, 21 days in. Final week.....
The buds 13-14in down on my branches are fat. Where if I were to have kept all those fan leaves on all the branches. No way would light make it down that far on a super dense bush.

The buds in the pic are from the plant on the left that already has been harvested. 17in down the branches and you find the bushy canopy. I'm allowing some under canopy to rippin while the amnesia haze on the right is 1-2wks out.