Uncle Ben
Well-Known Member
There is a difference between pruning to achieve training results and excessive removal of the unit that produces your bud. "Exposed budsites" are not capable of increasing yield, the photosynthetic tissue mass just isn't there. Many times when leaves or branches are removed the plant responds with replacement. Depends on timing and location.
There is a reason why fan leaves have a large surface and why they extend out from the plant into the surrounding atmosphere. It has been a natural plant evolution resulting in the most efficient method of collecting photons for the plant's photosynthetic processes. Up to a point of light saturation (bleaching out of the chlorophyll), the more photons collected by the plant, the more plant material (tissue) it is capable of producing.
Since the discussing of leaf removal in its various forms is as old as the hills and repeats itself with every new crop of noobs, I'll post a series of discussions from different now defunct cannabis forums, posted years ago.
As posted at CW->
>Is it a good idea to remove fan leaves that block light to the lower branches or will this take energy away from the flowering?
>
Uncle Ben:
Rottytown and Joey gave a solid explanation that is botanically based. Leaves are the lifeblood of the plant... with a caveat - they have to be functional and productive. If those leaves are healthy and green and receiving good decent light, "leave" 'em alone. If they are yellow or prone to fungus attack, they can be safely removed without detriment to the plant's health as they are contributing little if any value regarding food production - and this is The Key. If they are quite low on the plant and not receiving much light, then mother nature has a way of first taking the goodies from the leaf and it's petiole (removing stored food reserves/metabolites) and dropping the leaves anyway - moot point, eh?
>Even though I've tied the branches down horizontally, many branches are now shaded by large fan leaves.
>
Don't worry about shading branches, worry about shading leaves. Lower branches will always be shaded if your main light source is overhead. Add side lighting or use highly efficient side reflecting panels to alleviate this situation to a degree.
BTW, notice how large fan leaves are? Ever wondered why? It's because they are the most efficient food producing unit for the plant. It's your call (while understanding their function) regarding what to do with them at any given point in time.
>The lights have been on 12/12 for about 3 weeks and the plants are flowering if this helps.
>
I grow the most amount of foliage going into 12/12 as possible. While folks are doing the 15-30-15 thingie, I'm providing plenty of N to support foliage production. In general, lot's of foliage=lot's of flowers. Once sexed and the stretch is over, then you need to back off the N and increase the P and K with a blend like Peter's Blossom Booster, an excellent blend from an old pro who I hit on once in a while. Call Jack up, he's a great resource - http://www.jrpeters.com/moreblooms.html
Bottom line? It is your call to determine what is most important to the plant during flowering - large, efficient fan leaves or small, ineffective bud leaves. Choose carefully regarding targeting fan leaves for removal or tucking them away, as their exposure to quality light is The Key.
Good luck,
Uncle Ben
As posted at cann.com->
Thunderbunny:
In his book "marijuana botany" Robert Connell Clarke states that:
Leafing is one of the most misunderstood techniques of drug cannabis cultivation.
He states that there are 3 common beliefs:
1.) Large shade leaves draw energy from the flowering plant and by removing the large fan leaves surplus energy will be available and larger floral clusters will be formed,
2.) Some feel that the inhibitors of flowering , synthesized in the fan leaves during the long noninductive days of summer, may be stored in the older leaves that were formed during the noninductive photoperiod. Possibly, if these inhibitor-laden leaves are removed, the plant will proceed to flower more quickly when the shorter days of fall trigger flowering
3.) Large fan leaves shade the inner portions of the plant, and small, atrophied, interior floral clusters may begin to develop if they receive more light.
Few, if any, of the theories behind leafing have any validity.
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. They do create shade, but at the same time thay are collecting valuable solar energy and producing foods that will be used during the floral development of the plant. Premature removal of the fan leaves may cause stunting because the potential for photosynthesis is reduced.
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) He also states that removing large amounts of fan leaves will also interfere with the metabolic balance of the plant. Leaf removal may also cause SEX REVERSAL resulting from a metabolic imbalance
He goes on to say that cannabis grows largest when provided with plentiful nutrients, sunlight, and water, and left alone to grow and mature naturally. It must be remembered that any alteration of the natural life cycle of cannabis will affect productivity.
This book has served me very well in my 12+ years of growing--I would have to side with RC on this one--those sunleaves are there for a reason--they dont grow just for show--leave them on there and let that plant grow naturally
Good Luck,
Thunderbunny
There is a reason why fan leaves have a large surface and why they extend out from the plant into the surrounding atmosphere. It has been a natural plant evolution resulting in the most efficient method of collecting photons for the plant's photosynthetic processes. Up to a point of light saturation (bleaching out of the chlorophyll), the more photons collected by the plant, the more plant material (tissue) it is capable of producing.
Since the discussing of leaf removal in its various forms is as old as the hills and repeats itself with every new crop of noobs, I'll post a series of discussions from different now defunct cannabis forums, posted years ago.
As posted at CW->
>Is it a good idea to remove fan leaves that block light to the lower branches or will this take energy away from the flowering?
>
Uncle Ben:
Rottytown and Joey gave a solid explanation that is botanically based. Leaves are the lifeblood of the plant... with a caveat - they have to be functional and productive. If those leaves are healthy and green and receiving good decent light, "leave" 'em alone. If they are yellow or prone to fungus attack, they can be safely removed without detriment to the plant's health as they are contributing little if any value regarding food production - and this is The Key. If they are quite low on the plant and not receiving much light, then mother nature has a way of first taking the goodies from the leaf and it's petiole (removing stored food reserves/metabolites) and dropping the leaves anyway - moot point, eh?
>Even though I've tied the branches down horizontally, many branches are now shaded by large fan leaves.
>
Don't worry about shading branches, worry about shading leaves. Lower branches will always be shaded if your main light source is overhead. Add side lighting or use highly efficient side reflecting panels to alleviate this situation to a degree.
BTW, notice how large fan leaves are? Ever wondered why? It's because they are the most efficient food producing unit for the plant. It's your call (while understanding their function) regarding what to do with them at any given point in time.
>The lights have been on 12/12 for about 3 weeks and the plants are flowering if this helps.
>
I grow the most amount of foliage going into 12/12 as possible. While folks are doing the 15-30-15 thingie, I'm providing plenty of N to support foliage production. In general, lot's of foliage=lot's of flowers. Once sexed and the stretch is over, then you need to back off the N and increase the P and K with a blend like Peter's Blossom Booster, an excellent blend from an old pro who I hit on once in a while. Call Jack up, he's a great resource - http://www.jrpeters.com/moreblooms.html
Bottom line? It is your call to determine what is most important to the plant during flowering - large, efficient fan leaves or small, ineffective bud leaves. Choose carefully regarding targeting fan leaves for removal or tucking them away, as their exposure to quality light is The Key.
Good luck,
Uncle Ben
As posted at cann.com->
Thunderbunny:
In his book "marijuana botany" Robert Connell Clarke states that:
Leafing is one of the most misunderstood techniques of drug cannabis cultivation.
He states that there are 3 common beliefs:
1.) Large shade leaves draw energy from the flowering plant and by removing the large fan leaves surplus energy will be available and larger floral clusters will be formed,
2.) Some feel that the inhibitors of flowering , synthesized in the fan leaves during the long noninductive days of summer, may be stored in the older leaves that were formed during the noninductive photoperiod. Possibly, if these inhibitor-laden leaves are removed, the plant will proceed to flower more quickly when the shorter days of fall trigger flowering
3.) Large fan leaves shade the inner portions of the plant, and small, atrophied, interior floral clusters may begin to develop if they receive more light.
Few, if any, of the theories behind leafing have any validity.
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. They do create shade, but at the same time thay are collecting valuable solar energy and producing foods that will be used during the floral development of the plant. Premature removal of the fan leaves may cause stunting because the potential for photosynthesis is reduced.
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) He also states that removing large amounts of fan leaves will also interfere with the metabolic balance of the plant. Leaf removal may also cause SEX REVERSAL resulting from a metabolic imbalance
He goes on to say that cannabis grows largest when provided with plentiful nutrients, sunlight, and water, and left alone to grow and mature naturally. It must be remembered that any alteration of the natural life cycle of cannabis will affect productivity.
This book has served me very well in my 12+ years of growing--I would have to side with RC on this one--those sunleaves are there for a reason--they dont grow just for show--leave them on there and let that plant grow naturally
Good Luck,
Thunderbunny
