Cutting fan leaves with LST?

Is it ok to clip fan leaves on a LSTd plant? I know that's usually not a good idea, but I have some that are literally on the surface of the soil or directly on top of other leaves. Should I just leave 'em? I have good air circulation and RH is 50-60%. All opinions appreciated.

When I train a plant and bend it lets say to the right. now a side branch is vertical. I remove that fan leaf below the side branch to help the new growth along. depending on your light, light will penetrate a leaf enough to provide light to the leaf below but thats about it. the leaf below that doesn't get much light at all is really just your plants storage of nutrients. If you leave it eventually your plant will use it and it will turn yellow and die. A lot of times you need to remove them to get circulation but that doesn't sound like the case here.

You can remove leaf, your plant will just grow another one if it needs it. I would remove any leaf that's touching the soil.

You tell me...


About 2 weeks worth of time.

You can remove leaves, it won't hurt your plant in the way other's (who have never done it) would have you believe.

I defoliate my LST'd plants like a mad man. Taking fistfuls every 4 or 5 days. Plants grow more leaves than they need because in the wild they lose leaves regularly. The stress response also strengthens the plant and results in long term gains.

I will never treat fan leaves like they were made of gold again. You can see just what I'm talking about in my pictures.

Exactly what I needed to know. Thanks a lot guys. +rep for both

Great info. I was under the impression that removing fan leaves was an absolute sin.

No way man, Like snow said, you have to do it in a small space or your plant can smother itself.

Hell, My buddy did his first outdoor grow, didnt know what he was doing but knew what colas looked like so he removed EVERY fan leaf off the plants he had outside in the yard. I couldnt believe it when I saw it but they grew more sun leaves and made huge colas. I myself pulled over a trash can full out of my green house grow on one occasion. Just gotta be sure she is healthy and wont need the stored nutes soon.

SkunkDunks said:

Great info. I was under the impression that removing fan leaves was an absolute sin.

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Most people are.
It is just a band wagon though, everyone jumps on it because they don't really know any better.

I must also add that I stop defoliating after the first week of flowering. The plant stops producing much vegetation as it shifts gears to flower and leaves removed after that point will not be replaced with more leaves. Around a week before the end of flowering, when the plants are swollen and just need to ripen, I do thin them out a little bit just to keep ventilation around those monster nugs. Seems like at that point the "sugar" leaves can carry out all the photosynthetic action the plant needs.

There is a community of growers who all started on these forums maybe 2-3 years ago who refuse to prune. They just don't get it. I'm hoping the newer generations of growers will benefit from a reasonable approach to growing.

Bottom line, don't take anyone at their word. Look for evidence from them. Then try it out for yourself and see if you like it. If you don't like to prune it's not that big o'deal.

85% of light that strikes a leaf passes through it. The lower areas of plants appear to the human eye to not be receiving adequate light because the chlorophyll in the leaves reflect green light and the human eye is most sensitive to human light. Green light is not important to plants but they will continue to thrive on the light spectrum, colors, they do receive that the human eye is less sensitive and makes the lower portions of plants appear to have low light conditions and inadequate light.

If a plant is not receiving adequate light to it's lower portions the problem is no too many upper leaves for the light to penetrate. The problem is inadequate lighting. The solution to inadequate lighting is not to remove important and needed fan leaves. The solution is to upgrade, to increase your lighting.

Leaves are far more than just storage facilities for nutrients. They take in light and process it along with nutrients to create energy that is then stored. Fan leaves are not only storage facilities, they are also 'factories' where essential sugars/carbohydrates are created before then being stored. First the local leaves will be filled with stored energy and once filled the energy will be transferred to other leaf locations. If you remove fan leaves, the 'factories,' you reduce light intake, you reduce creation of energy and you reduce locations for energy storage.

During hours of light plants perform almost every single function the perform even with all their leaves on and in full sun their ability to produce as much energy is needed is limited so they have to allocate energy fir different needs, each receiving only a limited amount of energy.

During hours of darkness most plant functions shut down and the plants rely on stored energy, a battery backup could be a way to say it. Most energy is allocated for growth and when in flower for resin and THC production. If someone removes healthy leaves there is less stored energy for the plants to rely on during hours of darkness and that means reduced growth and when in flower less resin and THC production during hours of darkness.

A great deal of growth occurs during hours of darkness. Who here has looked at their plants and checked the distance between the tops of their plants just before their lights turned off and there appeared to be an adequate safe distance, but when you looked at them in the morning the tops of the plants were then very close to your lights, or even grown up into them and were touching the bulbs or were around the bulbs? It took a great deal of stored energy to get that much growth during those hours of darkness.

THC works as a sunscreen in trichome heads. IT protects the delicate inner glands and membranes from damaging light rays. Each day a percentage of THC is degraded while protecting the delicate inner workings of trichome heads. During hours of darkness large amounts of stored energy are used to replace the amount of THC that was lost plus produce even more so there is a slow gradual increase in the overall amount of THC during flowering. With less energy to rely on that process is hampered. Since most THC production/buildup occurs during hours of darkness it would be an injudicious thing for someone to do to reduce the amount of energy plants have to rely on during hours of darkness by removing any healthy fan leaves.

Brick Top said:

85% of light that strikes a leaf passes through it. The lower areas of plants appear to the human eye to not be receiving adequate light because the chlorophyll in the leaves reflect green light and the human eye is most sensitive to human light.

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Can you site a source for this information. I find it very hard to accept this as truth. 85% of the light is a great deal of light. Plants grow on the visible spectrum. It follows that if 85% of this light is present that my eyes would be able to detect the reflection of this 85% strength light. A simple test for someone with a ppfd meter would be to test the light intensity at a distance, then to place a leaf directly over the photo-receptor. The meter will then measure the intensity of the light after it passes through a leaf.

Anyone have a meter? I'd really like to see this in action. If it is true then it would change some of my habits, and I am in the pursuit of perfection after all. No need for me to be narrow minded

Experience tells me this is not the case, at least not for Marijuana. If you could provide me with a factual reference to your claim that would totally change my mind. I'm not a very stubborn person, but I think my pictures are pretty telling that a little defoliation does not hurt the plant in the slightest.

I do agree that pruning should be done only after everything else is squared away. It's kinda like CO2. Adding CO2 to a room with insufficient lighting, poor environmental control, and to over/under fertilized plants isn't going to turn out as well as one would hope. In comparison, defoliation should really only be applied with adequate lighting, in a controlled environment, and only to healthy plants. Defoliation has worked better for me outdoors, especially in a green house, but this might have to do with the strength of the sun. HumboldtLocals (a serious, serious med grower) swears by defoliation in his green houses now that he's seen the effects it has had. He's over at another forum... But has a good following and you can google his Outdoor 2010 grow to get an idea of just what he did with a little defoliation in a green house.

It's a fact that the plant produces more leaves than it needs. It is a fact that the stress response encourages hormonal production and increased vegetative growth of leaf mass. These are regular occurrences in nature in response to pests and disease. The whole "transparency" of leaves is something I'm not exactly ready to start preaching myself. I'd need more evidence to make a decision on that statement.

If it cannot be backed up then it would be pretty easy to refute.

Snow Crash said:

Can you site a source for this information. I find it very hard to accept this as truth. 85% of the light is a great deal of light. Plants grow on the visible spectrum. It follows that if 85% of this light is present that my eyes would be able to detect the reflection of this 85% strength light.

Experience tells me this is not the case, at least not for Marijuana.

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Four members of my family have degrees in botany and they have told me how much light passes through leaves, we own a pot-in-pot nursery that covers roughly 17 acres of land, we know growing, I have nearly four decades of 'home growing' of our beloved plant and have seen the results of virtually every type of growing method. Even though uneducated growers and those who love to jump on every fad growing method bandwagon like, want and need to believe that cannabis plants exist totally outside the realm of all botanical sciences they do not, they are not plants that are outside the realm of botanical sciences.



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 (Shipperke, Books:Nature:Horticulture, Botany. Here is another of these very handy field ... "Complete Schipperke" 1993 1st ed. book by Schipperke).

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 (Shipperke). 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 (Shipperke). 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. Sources give photosynthate to sinks in closest proximity. Upper leaves bring sucrose to shoot apical meristem and young leaves while lower leaves bring goodies to roots. Remove the source and the sink will be affected (Diels Alder).

The leaves at the top of a plant tend to supply the top growing shoots. The leaves at the bottom of the plant tend to supply the roots. The middle leaves can go either way as the demand changes. During flowering and fruiting, only the very bottom leaves supply the roots and the rest of the leaves try to get as much energy as possible to the flowers of fruits. For this reason, the more leaves are unshaded and in good light, the more chance the plant has of creating extra storage of energy that will ultimately go into yield.

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 (Higstar).
Nutrient burn usually causes bottom leaves begin to die however if you do not remove the leaves then they will absorb damage as premature removal generally results in more leaf loss. However if growing hydroponically under ideal conditions it could be argued that fan leaves serve as a nutrient buffer is a moot point.


Nuff said?

Snow Crash said:

It's a fact that the plant produces more leaves than it needs.

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It is not a fact that the plant produces more leaves than they need. Plants, when able to grow in optimal conditions, will maintain as equal as possible a 50/50 ratio between leaf area and root-mass area. That is essential for optimal growth and plant health. Leaf numbers and root-mass go hand in hand and one does not outgrow or out produce the other when growing in optimal conditions and anything less will result is less than optimal growth and less than optimal production. Neither roots or leaves are produced in numbers/area of mass that are larger or more than are needed.

That is a scientifically proven botanical fact that no amount of fad growing techniques or self dreamed up beliefs will ever be able to disprove.

I'm not going to be able to disagree with much of what you've said Brick Top. Very little of that is something I could argue against because I either don't have first hand knowledge (as to your family) or the resource (as the the book referenced). I do have some experience, and fairly good education (despite it being in physics and chemistry rather than botany) and I can view this subject with a very open mind.

The only thing I have to point to, are my personal experiences. It is very, very clear in the pictures I have provided that the EXTREME defoliation I applied to my plants in the "experiment" tent (yes, I have a bloom tent, a mother tent, a clone tent, and an experimental tent) has had a very desirable effect. The side branches most definitely are more mature, the leaf mass is most definitely present, and though I haven't reached harvest of this plant yet (another 7 weeks probably) I do expect the presence of mature side branches to result in a heavier harvest. Having a control plant would have been a good idea to present the contrast of techniques but this is a strain I have had a few harvests with and know what to expect from it myself. I think if I can take you at your word, regarding your education, then I think you should be able to take me at my word here as well. Defoliating this plant has resulted in a better plant than I've ever seen with this strain, Lemon Skunk from GHS.

I very much appreciate the time it must have taken to write this. I'm still unconvinced though, because what you've stated I've heard before, and the experience of defoliation does not back up the theory you are basing your statements on. To refer to the scientific method, it would seem that what you are saying is more Hypothesis. What I have shown is the results of the experiment. In this specific case it would seem that the hypothesis of "slowing the plant down and doing more harm than good due to the role of large fan leaves" is incorrect when you view the results.

When I examine the evidence as set forth it would appear that a reasonable conclusion is that your hypothesis is incomplete and an unstated process is occurring which is eliminating the negative effects of defoliation. I think everyone needs to make up their own minds, to try it, and to come to their own conclusion rather than stopping at the hypothesis. I will continue to employ both methods in my own garden as I've given it a shot and I personally like what I see. I encourage others to do the same.

Thanks for all that info man! I'm still learning the ropes, even after half a decade of growing, and will be applying much of what you've stated in my next experimental grow.

Snow Crash said:

I'm not going to be able to disagree with much of what you've said Brick Top. Very little of that is something I could argue against because I either don't have first hand knowledge (as to your family) or the resource (as the the book referenced). I do have some experience, and fairly good education (despite it being in physics and chemistry rather than botany) and I can view this subject with a very open mind.

The only thing I have to point to, are my personal experiences. It is very, very clear in the pictures I have provided that the EXTREME defoliation I applied to my plants in the "experiment" tent (yes, I have a bloom tent, a mother tent, a clone tent, and an experimental tent) has had a very desirable effect. The side branches most definitely are more mature, the leaf mass is most definitely present, and though I haven't reached harvest of this plant yet (another 7 weeks probably) I do expect the presence of mature side branches to result in a heavier harvest. Having a control plant would have been a good idea to present the contrast of techniques but this is a strain I have had a few harvests with and know what to expect from it myself. I think if I can take you at your word, regarding your education, then I think you should be able to take me at my word here as well. Defoliating this plant has resulted in a better plant than I've ever seen with this strain, Lemon Skunk from GHS.

I very much appreciate the time it must have taken to write this. I'm still unconvinced though, because what you've stated I've heard before, and the experience of defoliation does not back up the theory you are basing your statements on. To refer to the scientific method, it would seem that what you are saying is more Hypothesis. What I have shown is the results of the experiment. In this specific case it would seem that the hypothesis of "slowing the plant down and doing more harm than good due to the role of large fan leaves" is incorrect when you view the results.

When I examine the evidence as set forth it would appear that a reasonable conclusion is that your hypothesis is incomplete and an unstated process is occurring which is eliminating the negative effects of defoliation. I think everyone needs to make up their own minds, to try it, and to come to their own conclusion rather than stopping at the hypothesis. I will continue to employ both methods in my own garden as I've given it a shot and I personally like what I see. I encourage others to do the same.

Thanks for all that info man! I'm still learning the ropes, even after half a decade of growing, and will be applying much of what you've stated in my next experimental grow.

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I think what turns discussions like this into a slog-fest is a common simple misunderstanding. Cannabis plants are rough tough survivors and they can and will produce well in less than optimal conditions. There are growing methods that if used will produce well. Your pictures are evidence of that. Based on them I would say you outgrow most members here. Where the misunderstanding comes in is when someone offers actual proof of how plants will be healthier and produce better it is sometimes taken by someone using a growing method like you, and who does well with it, as a claim that they do not know what they are doing, that you do not get good results and that you cannot get good results and it can be taken as a personal attack when it was not intended as such. If that happens people become defensive and they tend to go all out to defend what they do and what they believe in.

The problem to someone with a bit more botanical information is pictures, or evidence, of good results do not refute facts so they will continue to insist that facts are facts, they also become defensive because what they know to be facts are being challenged and claimed not to be factual. Personal emotions enter into what would hopefully be a totally non-emotional exchange. Things heat up and it all goes downhill from there.

Over my nearly four decades of growing I have seen plants grow in conditions I would never have expected them to be able to survive in, but they not only survived, they produced fairly well or even better than just fairly well. Many people virtually torture their plants and can still end up with respectable yields ... but that should never be taken as proof that such growing methods are the best or will produce the most. It is only proof that cannabis plants can take a licking and keep on ticking .. and nothing more.

One other thing I believe I failed to mention is ... many people say that genetics are everything ... heck, I have said it myself in the past. But while genetics are very important, all they guarantee is the opportunity for quality herb. Growing conditions/environment actually account for roughly 50% of success or failure. Someone could grow the way I write about and how Uncle Ben writes about but not do it under optimal or near optimal conditions and their results could easily be dismal. They could grow like you do or like some others do and do so in optimal or near optimal conditions and their results could easily outshine the previous example.

That in part explains why some people have come to believe that certain methods that run contrary to botanical sciences tell you things should occur are actually better. The very best growing method when performed under less than optimal, or under terrible conditions, will not outproduce a terrible growing method that is done under optimal growing conditions but no growing method will outperform, outproduce, the very best growing method even if all are done under optimal conditions.

The very best of us seldom achieve truly optimal conditions. There will always be some fly in the ointment that reduces the conditions/environment to some degree or another. In the end it comes down to what works best for each individual, but even that is not proof it is the best overall. It is only proof that it is best for that grower when growing under the best conditions/environment they can achieve and since everyone's conditions and environment will differ it should never be claimed to be the best of the best.

I do have a question about your GHS Lemon Skunk. Did you end up with more than one phenotype? I have grown it twice and have seen three different phenotypes and one was a pain in the butt. One was very, very sativa predominant, by it's looks it could be guessed to have been a pure sativa. It was nute finicky. The other two, one that looked like the cross would be expected to look and one that looked very indica-like, with wide paddle-leaves that looked like blades on a ceiling fan, were happy go lucky easy going simple plants to grow.

With all being fed exactly alike the uber-sativa phenotype developed nitrogen toxicity resulting in 'the claw.' It also shot up like Jack's magic beans and was a real pain when I ran out of growing height. It dwarfed the others. I was just curious if you experienced anything similar or if you were luckier than I was and saw fewer phenotypes, or possibly only one.

Brick Top said:

The very best of us seldom achieve truly optimal conditions. There will always be some fly in the ointment that reduces the conditions/environment to some degree or another. In the end it comes down to what works best for each individual, but even that is not proof it is the best overall. It is only proof that it is best for that grower when growing under the best conditions/environment they can achieve and since everyone's conditions and environment will differ it should never be claimed to be the best of the best.

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I completely agree. There are a tremendous number of variables to account for and there are very few "truths" when it comes to personal preference and in the moment responses. There are many facets of a person's life that require a "middle of the road" approach, and I think how they cultivate is one of those sides. Very well stated.

Brick Top said:

I do have a question about your GHS Lemon Skunk. Did you end up with more than one phenotype? I have grown it twice and have seen three different phenotypes and one was a pain in the butt. One was very, very sativa predominant, by it's looks it could be guessed to have been a pure sativa. It was nute finicky. The other two, one that looked like the cross would be expected to look and one that looked very indica-like, with wide paddle-leaves that looked like blades on a ceiling fan, were happy go lucky easy going simple plants to grow.

With all being fed exactly alike the uber-sativa phenotype developed nitrogen toxicity resulting in 'the claw.' It also shot up like Jack's magic beans and was a real pain when I ran out of growing height. It dwarfed the others. I was just curious if you experienced anything similar or if you were luckier than I was and saw fewer phenotypes, or possibly only one.

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Oh yeah, in just 5 seeds I got 3 different Phenotypes.


These two plants had very interesting leaves. They were stretchier, more sativa dominant, and you can see that "clawing" you were talking about. Probably the same pheno you mentioned. The leaves of these plants had a unique "T-Rex tooth" edge to them, where the serrated edges had a kind of hook to them. Really cool looking, but not an especially heavy producer. Need a bit extra Calcium during Veg and a bit more Magnesium during flowering. Good resistance to heat and humidity, probably thanks to the Sativa back bone.



These two plants were moderate in their vigor. Great lemon flavor and slow but steady growth. They showed poor tolerance to high ppm levels but that could be good as they don't require all that much food. In hindsight this Pheno would have been fantastic for topping as the steady growth really helped maintain an even canopy. (The sick plants in this picture are Blue Mystic, total princess to grow).



This plant is the one I chose as a mother. It was extremely vigorous, with a preference for high PPM media. This works out for me growing in coco. It is the mother for the plant I've shown defoliated earlier in our discussion. It is characterized by what I'd call a good 50/50 split of indica and sativa genetics. The fan leaves were smaller on this plant than the other ones, and I think this makes it a great candidate for training methods as the plant "spreads" the resources around between more smaller leaves rather than having a few very large leaves. They were also darker than the other plant's bordering on almost Blue/Purple in the older growth while still very healthy, and she has purple stems. She also produces nice big buds with a blue/white/purple hue and a very complex citrus flavor. It's lemon, but with a hint of lime, orange, and grapefruit. The high is definitely skunk, I do some "forgetful" stuff on it, but has a bit of that sativa-esque endless ceiling.

The variation in the genetics was odd because they all have the citrus flavor in the flowers, and a very skunky smell when shaken during flowering, but the growth patterns were so completely different. As I was growing them I got the feeling that the Rex Tooth would be better suited to outdoor life in soil, the even grower better as a SOG/Hydro/NFT, and the vigorous grower better as a Scroged plant in DWC or Coco. This variation, though not necessarily desirable, does allow someone to find exactly what they are looking for despite their methods.

You're not the only person to come to me with three phenos. I'm convinced they must have had some variation in the mother plants used to create the Fem'd seeds. Eventually I want to try the DNA Genetics Lemon Skunk as a comparison. I hear theirs is very Indica Dom.