keeping / leaving fan leaves on during trimming.

So I'm about to throw my plants into flower tomorrow so I've been trimming.

But I HAVE been leaving the lower fan leaves on. The way I look at it is that the fan leaves are extra foliage for photosynthesis without adding a bud sight that would be low producing anyway. Has anyone done this?
 

FarmerJJ

Member
I've read that it is a good idea to keep the fan leaves during flowering, as they do produce more usuable energy to the plant from photosynthesis, also removing the leaves does cause stress that could potentially defuse floral hormones. Plus the buds store more energy than they produce. So i would just remove them when 50% or more dead/damaged like usual.

P.s, I think there's probably a better place to post this question
 
K Farmer JJ, thanks for the reply but I think you've both misunderstood my question. I'm just talking about the lower fan leafs, not the fan leafs that would be blocking buds from the light

This is what I mean
PICT0375.jpg


See how the fan leaf on the bottom and the fan leaf to the right of it are both missing their shoots? Just taking off the shoot but not the fan leaf cause any stress?
 
It should not stress your plant, although that branch is pretty thick now, you should be fine. You can trim them or not, some do some don't. I would remove em.
 

gobbly

Well-Known Member
There are kinda two philosophies on this. The first is that by removing lower growth that won't produce much you are allowing more energy to go into the top cola production. The other way to look at it is that those leaves and stem structures hold mobile nutrients that the plant can suck back up and put toward new growth. With that in mind it's quite possible it is going to depend on nutrient uptake, how much growing area it has and other factors like that.

I personally go with the second philosophy and leave it all on. The plant itself always seems to pick what it doesn't want and drops them off after a while anyway. I've not seen someone who did any real studies on this (side-by-sides with large sample sizes, as well as control).
 

Brick Top

New Member
Oh my dear God ... not ANOTHER thread on this subject.

To quote Yogi Berra; "This is just like déjà vu all over again.”


The large fan leaves have a definite function in the growth and development of cannabis. Large leaves serve as photosynthetic factories for the production of sugars and other necessary growth substances. Most cannabis plants begin to lose their larger leaves when they enter the flowering stage and this trend continues on until senescence (death of the plant).

Fan leaves account for the greatest area for the reception of photons on a plant, thus they account for the majority of photosynthesis which occurs within a plant. Cells in the plant's leaves, called chloroplasts, contain a green pigment called chlorophyll which interacts with sunlight to split the water in the plant into its basic components. Leaves only absorb about 15% of the solar energy that hits them, the other 85% passes through-- but they reflect all the green light, which means it looks darker below the leaf to a human than it does to the plant because our eyes are most sensitive to the green spectrum.

Photosynthesis occurs in all green parts of plants. The process has two stages, the light reactions and the Calvin cycle, that convert water and carbon dioxide into sugar and oxygen. These sugars are later used to power all the processes in the plant, including the synthesis of THC and other cannabinoids. Fan leaves possess the greatest number of stomata, which are small pores or valves on the underside of the leaf which water vapor and carbon dioxide diffuse during transpiration and photosynthesis (carbon fixation). Carbon dioxide first enters the leaf through the stomata and combines with the stored energy in the chloroplasts through a chemical reaction (the Calvin cycle) to produce a simple sugar. This sugar is unloaded into the tissues and transported through tubes in the leaf to supply the synthesized food to other plant parts such as growing or respiring tissues like young leaves, roots, and flowers of the plant meristems.

Removal of fan leaves will not only slow growth, but it will also hinder the plants ability to rid itself of toxic gases, and also hinder the regulation of the plants temperature via stomata. Changes in the plants chemical metabolism caused by fan leave removal causes the plant to work overtime to rid ‘toxins’ with less leaves, as a result the pant may allocate more growth hormones into growing more leaves to make up for what has been lost. Removing large amounts of fan leaves may also interfere with the metabolic balance of the plant. Leaf removal may also cause sex reversal resulting from a metabolic imbalance.

There is a relationship regarding the amount of carbohydrates a leaf produces and CO2 intake relative to outside forces. When you have a situation whereby the leaf is no longer productive for the plant for whatever reason that may be - low light, old age, disease, insect attack etc, the plant will discard it.

Plants have two different kinds of vessels in their stems to move stuff around, xylem and phloem. Xylem runs from the roots up the stem carrying water and nutrients. Phloem runs both up and down to move sugars hormones, proteins, etc but mostly sugars. Each part of the plant can be either a sugar source or a sugar sink. Phloem moves from sources (areas of supply) to sinks (areas of metabolism or storage). Granted that the flowers can produce some photosynthate, but they are no where near as effective as fan leaves (resin glands significantly reduce light to the tissue they are found on). Flowers are sink tissues, leaves are source tissues. Sinks do not produce enough photosynthate, and are importers.Remove the source and the sink will be affected.

Fan leaves store mobile nutrients, these stored nutrients are essential in the later stages of flowering. When flushing a plant the fan leaves will lose their color quickly. This is because the nutrients are being mobilized to the atypical meristem (grow tip, bud site). Draining your fan leaves with a flushing period will increase floral development. Fan leaves therefore serve as a nutrient deficiency buffer zone for the plant.

Light efficiency decreases with distance. The inverse squared light rule states that illuminance is inversely proportionate to the square of the distance from the light source.

Removing the largest area of photosynthesis that is closest to the light source simply to benefit smaller leaves growing out of the bud sites that are further away is not logical.


An alternative to trimming to increase light to lower floral clusters is to upgrade/improve your lighting and or use a light mover. The results are better thanks to increased lighting and the better penetration of light at different angles.
 

Total Head

Well-Known Member
i swore i would never post in another one of these fan leaf threads again, but i just have to throw this suggestion out. if you want the fan leaves gone just cut back on the n more than usual during flower. then they will croak all on their own when they feel like it. both options are bad for the plant and eliminate fan leaves, but my option could save $$.
 

spandy

Well-Known Member
Stupid mother nature putting all these leaves in the way. What was that bitch thinking? It amazes me that plant life survived this planet for so many years before us humans figured out it was all wrong.

My comment above is pure sarcasm for those of you who are brain dead.

Remove them when they hit the floor on their own.
 

Brick Top

New Member
Stupid mother nature putting all these leaves in the way. What was that bitch thinking? It amazes me that plant life survived this planet for so many years before us humans figured out it was all wrong.

My comment above is pure sarcasm for those of you who are brain dead.

Remove them when they hit the floor on their own.
I figured it was an evolutionary error ... Darwin should have caught it.

JOKE!
 

Pullin' weeds

Well-Known Member
"...simply to benefit smaller leaves growing out of the bud sites that are further away is not logical."


But it's those leaves that we want to maximize!!!

Yes, in a perfect place, for the good of the PLANT you would want to leave every single leaf it put there, just as mom nature intended - if you wanted the biggest plant you could, out in the sun, that would in turn produce lots of nutritious and reproductive seeds.
But I don't, I want small plant that grows inside and tolerates all sorts of bending, and yes - maximizes the BUD LEAF.
Selectively opening the canopy by selective trimming of fan leaves in favor of buds can IMHO definately pack weight on the lower parts of the bud, making a much much heftier bud.
 

Pullin' weeds

Well-Known Member
People do all sorts of unnatural things to themselves- They exercice excessively, pump themselves full of steroids and growth factors. I'm not saying it's good - they negatively affect other parts of their body etc... It certianly isn't natural.
But they are definately bigger and stronger than I'd ever be.
 
No shit. They're either too lazy and/or rude to do a simple search.
Looks like you need to take another look at YOUR link http://www.starterupsteve.com/swf/posting.html?
What does your post add to the intellectual community of the forum? (rhetorical question, no need to respond) hah.

No wonder so many people end up leaving riu, so much hate.

Anyway, lets get back to the reason why my question is different than other trimming fan leave questions and lets add to the intelligence of the community :D.

1) I'm NOT talking about removing fan leaves that shadow or "block" bud sights. i know there are thousands of posts on this subject.
2) To be as technical as I can possibly be, I am talking about NOT trimming the fan leaves when trimming it's corresponding vegetative shoot.

So to reiterate my question, does doing as 2) describes stress the plant anymore than hacking off both the lateral shoot and its corresponding leaf?

Why would I do this you ask? a) you can go look at my original question (although most people haven't read it anyway and just read the title) or right here (and I'm called lazy??? lol)

We know most people trim the lower lateral branches right before flower because the bud produced from these sights is fluff compared to the upper portions. But what I ask is why NOT leave the fan leafs on of these lower portions? (unless its known to severely cause stress which what I'm asking)

So no, there was no other forum post which had answered my SPECIFIC question.
 

Uncle Ben

Well-Known Member
Looks like you need to take another look at YOUR link http://www.starterupsteve.com/swf/posting.html?
What does your post add to the intellectual community of the forum? (rhetorical question, no need to respond) hah.

No wonder so many people end up leaving riu, so much hate.

Anyway, lets get back to the reason why my question is different than other trimming fan leave questions and lets add to the intelligence of the community :D.

1) I'm NOT talking about removing fan leaves that shadow or "block" bud sights. i know there are thousands of posts on this subject.
2) To be as technical as I can possibly be, I am talking about NOT trimming the fan leaves when trimming it's corresponding vegetative shoot.

So to reiterate my question, does doing as 2) describes stress the plant anymore than hacking off both the lateral shoot and its corresponding leaf?

Why would I do this you ask? a) you can go look at my original question (although most people haven't read it anyway and just read the title) or right here (and I'm called lazy??? lol)

We know most people trim the lower lateral branches right before flower because the bud produced from these sights is fluff compared to the upper portions. But what I ask is why NOT leave the fan leafs on of these lower portions? (unless its known to severely cause stress which what I'm asking)

So no, there was no other forum post which had answered my SPECIFIC question.
Your issue and many others has been sliced and diced every which way but Sunday in a thread called "Lollipopping". Suggest you give it a read.

Why anyone would want to remove a healthy leaf is beyond me.

"Stress" (and energy) is slung around loosely here. You stress out a plant when you don't water enough, or give it too much food. "Stress" is reflected by poor vigor, loss of leaves, stunting, etc., not by some popular forum thought i.e. - LST, the latter being an oxymoron.

UB
 
Top