The Haze discussion thread

[@hempy]

In plants, apical dominance prevents the development of lateral shoots. It can be overwhelmed by apical bud defoliation, allowing numerous lateral buds to develop into more lateral branches carrying more fruits and possibly increasing seed yield. This study tested this hypothesis on five hemp (Cannabis sativa L.) cultivars in a 2-year field experiment. In comparison to the intact ones, the defoliated plants developed several lateral shoots. The hemp seed yield was significantly influenced by the year of production, the apical bud removal, and the cultivar. The average two-year seed yield of the defoliated plants (715 ± 47 kg/ha) was significantly higher than the yield of the intact plants (568 ± 35 kg/ha). Absolutely the greatest effect of apical bud removal on the seed yield was observed for the cultivar ‘Novosadska konoplja’, where increase was 225 kg/ha (25%); a slightly smaller difference occurred for the cultivar ‘Uniko-B’ (183 kg; 30%), followed by ‘Juso-11’ (140 kg/ha; 27%) and ‘Bialobrzeskie’ (128 kg/ha; 29). Cultivar ‘Beniko’ presented the smallest difference with apical bud removal – 58 kg/ha (15%) yield increase We maintain that hemp producers can achieve a larger seed yield not only by selecting an appropriate cultivar and row distance but also by removing apical buds.
https://www.researchgate.net/publica...nabis_sativa_L

Effects of Defoliation in Grain HempKadie E. Britt and Thomas P. Kuhar
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
Chewing insects such as caterpillars, beetles, and grasshoppers are sometimes present in great densities on hemp plants
and can often consume a considerable amount of foliar material. Very little is known about the impact of defoliation on
hemp. In 2018 and 2019, an experiment was conducted to simulate insect defoliation on grain variety hemp plants (‘Felina
32,’ a dual-purpose grain/fiber variety) to determine whether a loss of foliar area could impact yield. This experiment was
conducted at Virginia Tech’s Kentland Research Farm in Whitethorne, VA. Hemp plants were manually defoliated with
shears to remove varying levels of leaf material from plants at varying times throughout the season. Plants were defoliated
at 20, 40, and 60 days post planting (to simulate early, mid, and late season insect infestations) at levels of 0%, 25%, 50%,
and 75% (to simulate damage at no, low, medium, and high levels of insect infestation). ‘Felina 32’ variety hemp plants
typically have a ~90 day growing season in the field. Seeding rate both years was 30 pounds of seed per acre. Planting dates
for this study were 8 June 2018 and 30 May 2019. The results from both years of this experiment showed that average seed
weight per hemp plant was not significantly affected by timing or amount of foliar area removed from plants. These results
confirm the popular belief that hemp is an extremely durable and tolerant crop. However, it is possible that actual insect
feeding injury rather than manual defoliation using shears could potentially elicit a different plant response. However,
similar experimental methods have been conducted in many other crops using manual defoliation and showed that plant
yield was significantly negatively affected. Also, although this experiment revealed that grain yield was not affected, it does
not provide any information as to whether chemical production of THC (tetrahydrocannabinol) or CBD (cannabidiol) is
altered. Future directions will explore potential chemical content alteration within grain and CBD variety hemp plants.

https://plantpathology.ca.uky.edu/files/sr112.pdf

Defoliation is simply the act of cutting leaves off a cannabis plant for the purpose of pruning. It is backed by scientific research that shows that older plant leaves do not contribute as much to plant growth as new, smaller leaves, but instead, they become detrimental.

According to research, as plants grow, so does the size of their leaves. Older leaves become larger, thereby taking up even more water, sunlight and other nutrients even though their ability to support photosynthesis and other necessary processes is more limited. Defoliation aims to eliminate these older leaves and rejuvenate the cannabis plant.

Larger yields

Defoliation has been proven to boost the yields you can get from your cannabis garden. There are two angles to this: the first revolves around the plant hormone ethylene, which is known to lower yields because of its ability to trigger aging processes within plant cells.

Per nature’s design, ethylene is found in higher concentrations in older leaves and flowers, such as those at the lower ends of the cannabis plant. Defoliation effectively nips these leaves and flowers, triggering higher yields for the plant.

The second angle revolves around defoliation’s ability to increase the exposure of leaves to sunlight and air, which directly stimulates more photosynthesis, better growth and larger yields by harvest time.

Efficient light absorption

https://greenrushpackaging.com/canna...wing-cannabis/

 

[Chi13]

Abstract and Figures

Hempy, your first link advocates the removal of the centre bud (apical bud), not general defoliation? Are you suggesting this? I though you were only talking about fan leaf removal.

Your second link does not show any benefit (or harm) from defoliating? Indeed it says: "However,
similar experimental methods have been conducted in many other crops using manual defoliation and showed that plant
yield was significantly negatively affected".

Your third link is good but again shows no evidence. It is frustrating that claims like this are made without links to actual studies? I would love to get to the bottom of this question.

This one is a good read:
"I believe defoliation is a misguided “production technique” that is costing the cannabis industry millions of dollars each year in lost profits, yet nobody has ever done any sort of study on it".

I’ve looked up defoliation studies on other plants to see if there are any common threads that might reasonably be applied to Cannabis as well.

These studies below all agree that pruning of less than 25% in the vegetative stage, doesn’t cause significant yield loss. This is encouraging news for Cannabis farmers because almost across the board, it seems pretty common, especially with indoor farmers, to thin the canopy to allow increased airflow – before the end of week three.

However once you get fully into the flower stage, the detrimental effects increase rapidly".

https://cannabis-science-consulting....ation-studies/

 

[@hempy]

No ones forcing any one to defoliate but like it or not many now in the community including industry ( large commercial growers that are focused squarely on profit ) are defoliating their plants.

They do it on cotton plants and other plants also.

Apical bud - The apical (Terminal) bud of a plant is the primary growing point located at the apex (tip) of the stem. It is the dominant bud, since it can cause all the Axillary (lateral) buds below them to remain dormant.

No evidence really ?

It is backed by scientific research that shows that older plant leaves do not contribute as much to plant growth as new, smaller leaves, but instead, they become detrimental.

According to research, as plants grow, so does the size of their leaves. Older leaves become larger, thereby taking up even more water, sunlight and other nutrients even though their ability to support photosynthesis and other necessary processes is more limited. Defoliation aims to eliminate these older leaves and rejuvenate the cannabis plant.

Defoliation has been proven to boost the yields you can get from your cannabis garden. There are two angles to this: the first revolves around the plant hormone ethylene, which is known to lower yields because of its ability to trigger aging processes within plant cells.

Per nature’s design, ethylene is found in higher concentrations in older leaves and flowers, such as those at the lower ends of the cannabis plant. Defoliation effectively nips these leaves and flowers, triggering higher yields for the plant.

The second angle revolves around defoliation’s ability to increase the exposure of leaves to sunlight and air, which directly stimulates more photosynthesis, better growth and larger yields by harvest time.

Efficient light absorption

You seam to be ignoring the facts mate.

You cant just choose the info you want to support your argument and ignore all the rest.

 

[Donald Mallard]

i think there is a little bit of confusion between severe defoliation ,
and some pruning ,,,
I do some pruning on my plants ,
but i leave all what i regard as essential leaf and simply trim some of the inners ,
that looks like what maryjane has done on his commercial crop too ,
id be very very surprised to see any commercial grows defoliating to the extent you have shown in your pictures ,
in fact i would go to the extent of saying there is no way they would do that for fear of losing money ...

 

[harvestreaper]

no one owns/can take credit for,, truth ,, it was already there we just rediscovering it lol ,,for me the value of these threads is the sharing of ideas Techniques pics etc so if someone presents you with a technique youve not seen you have the chance to try it and prove it to yourself one way or other ,lets not forget 30/40 years ago sharing like this was next to impossible ,,,its not about some court of law type bs were it needs to be proven absolutely here in cyberspace which is kinda impossible lol ,,either take the advice or leave it,, aint it great to have the choice to do whatever you want ,,everyone has there own view /understanding of life that cannot be replicated,,, thats beautiful ,,so to be progressive/scientific were forced to meet in truth which can be proven for all to see and it dont care what anyones personal take is ,,again beautiful ,,,but ultimately any /all truths must be proven to ourselves to have any value ,,,arguing aint getting anyone round that
disclaimer ...comment influenced by haze genetics and should be treated accordingly

 

[star crash]

 

[...CR500AF...]

i think there is a little bit of confusion between severe defoliation ,
and some pruning ,,,
I do some pruning on my plants ,
but i leave all what i regard as essential leaf and simply trim some of the inners ,
that looks like what maryjane has done on his commercial crop too ,
id be very very surprised to see any commercial grows defoliating to the extent you have shown in your pictures ,
in fact i would go to the extent of saying there is no way they would do that for fear of losing money ...

Bingo...

 

[Benny106]

Why let reason and common sense get in the way of online special Olympics

 

[Hammerhead]

I am all for discussion Hammer but the insults are not welcome.

Most here know you take any disagreement as an insult. Not possible to discuss anything with you and not get but hurt about it ..

 

[Cvh]

I created the following thread to discuss defoliating techniques.

https://www.icmag.com/forum/marijuan...foliate-or-not

Please move the defoliating debate to this thread. This makes it easier for everyone to participate, keeps the Haze thread on topic and all the posted info will not get lost.

Thanks everyone.

 

[CannaRed]

shwazzing nope never heard of it but just ran a google search and found this.


I first posted about my method in 2000/2001 all i got was ridicule.

Results and pictures dont lie but now the science has caught up.

Sorry, I wasn't trying to say you were ripping off the shwazzing technique. I was just asking you for a citation from your quote. I should have made a second post asking everybody if they remember shwazzing.

Schwazzing is technique of hard defoliation where they remove every single leaf with a visible petiole. They do it twice. I think day 1 and 20 of bloom.

The author of the book charged over $400 for that tech that you got from a hippy for free.

 

[Chi13]

shwazzing nope never heard of it but just ran a google search and found this.


I first posted about my method in 2000/2001 all i got was ridicule.

Results and pictures dont lie but now the science has caught up.

Well, the science hasn't caught up. In fact defoliating may be a myth. Don't take my word for it, please look at the links I posted. I only brought it up because you advocated removing all fan leaves.

 

[Chi13]

I created the following thread to discuss defoliating techniques.

https://www.icmag.com/forum/marijuan...foliate-or-not

Please move the defoliating debate to this thread. This makes it easier for everyone to participate, keeps the Haze thread on topic and all the posted info will not get lost.

Thanks everyone.

Sorry, posted before I saw this.

 

[@hempy]

Sorry, I wasn't trying to say you were ripping off the shwazzing technique. I was just asking you for a citation from your quote. I should have made a second post asking everybody if they remember shwazzing.

Schwazzing is technique of hard defoliation where they remove every single leaf with a visible petiole. They do it twice. I think day 1 and 20 of bloom.

The author of the book charged over $400 for that tech that you got from a hippy for free.

Nothing to be sorry for mate i my self had never heard of it before. So i went googled it and read up on it and coped and pasted the basic info for others who had not also.

I did a thread on it at Cannabis world decades ago and have shown it done in stages threw all my grow threads to.

Thinking out side the box is how you improve things.

 

[Donald Mallard]

Sorry, I wasn't trying to say you were ripping off the shwazzing technique. I was just asking you for a citation from your quote. I should have made a second post asking everybody if they remember shwazzing.

Schwazzing is technique of hard defoliation where they remove every single leaf with a visible petiole. They do it twice. I think day 1 and 20 of bloom.

The author of the book charged over $400 for that tech that you got from a hippy for free.

$400 for a book that has folks raping their plants of essential parts sounds like a real rip off to me ,
the guy is probably not even qualified in anything to do with horticulture or agriculture ,

a mate of mine showed me pictures of this method from a friend of his ,
my mate was very disappointed in the process,
the yield on the outdoor plants severely suffered,
growing the same varieties he said it was easy to see the disadvantage caused by "shwazzing" on their outdoor plants ...
i doubt indoor plants would have done much better either ...

 

[CannaRed]

Nothing to be sorry for mate i my self had never heard of it before. So i went googled it and read up on it and coped and pasted the basic info for others who had not also.

I did a thread on it at Cannabis world decades ago and have shown it done in stages threw all my grow threads to.

Thinking out side the box is how you improve things.

Is that how you do it? You remove every leaf with a visible petiole?

 

[@hempy]

Is that how you do it? You remove every leaf with a visible petiole?

I will pm you mate i am tired of being trolled and insulted in my own thread.

This needs to stop if i did half of what others did towards me i would be banned same should applier to them.

 

[CannaRed]

One of you guys with room do haze off. Side by side by side One control with every leaf intact
One with normal pruning
One with heavy defoliation.

But then we'd all argue about the definition of "normal pruning"

Someone quoted and linked Cocoforcannabis. I do really like that site.
I heard him say on a podcast that even when he (does what he calls "selective pruning") removes the lower branches where larf would form, that he leaves the fan leaf at that node. Ive done that before I ever found that site.
​​​​​​
Im not taking sides or arguing here, this is one of the many things that growers always argue about. I may be totally wrong here but I know that the plant can pull certain mobile nutrients from older leaves if it's needed elsewhere. So I always just left the lower leaves and removed the branches, thinking of the leaves as a backup of nutrient/mineral incase it was needed. ​​​​​

 

[maryjaneismyfre]

LOL I won't post a picture a day post defoliation as I'll be accused of plant abuse...You guys would not believe how bare and nekid the ladies look...Timed right and done right, most genetics don't notice, I have done this technique on hundreds of different individual plant (strains), Some benefit greatly, some benefit somewhat and a very few plants don't like it...If done right a week later the plant is unrecognizable to what it would be a week prior when naked, it has would have regrown the amount of leaves it needs to make buds and finish off its life...I'll take a side by side picture of a block heavily stripped of all fan leaves early in flower (it still has a layer of its last fan leaves on top) and a block that was left minimally plucked. All got bottoms cleaned up and pruned off of both blocks..They are 3.5 weeks into flower.. I don't play games, I plant high density and grow big buds...I get paid to grow flowers and not leaves.. I have done many side by sides LOL...Sometimes you guys are just anti everything Hempy does hahahahha and unfairly!

 

[mojave green]

The Benefits of Proper Defoliation When Growing Cannabis

In the cannabis industry and especially among cannabis growers, defoliation continues to be a divisive topic. Many people still believe that defoliation isn’t necessary for a growing cannabis plant. Those that acknowledge its importance are also still likely to disagree on what defoliation method works best and which doesn’t work at all.

But ultimately, defoliation is good for cannabis plants and there is enough scientific research to prove it. It’s important to note that defoliation is only beneficial to the plant when done right. This simple guide helps cannabis growers learn more about defoliation techniques, plus the specific benefits plants derive from being defoliated every once in a while.

What is defoliation?

Defoliation is simply the act of cutting leaves off a cannabis plant for the purpose of pruning. It is backed by scientific research that shows that older plant leaves do not contribute as much to plant growth as new, smaller leaves, but instead, they become detrimental.

According to research, as plants grow, so does the size of their leaves. Older leaves become larger, thereby taking up even more water, sunlight and other nutrients even though their ability to support photosynthesis and other necessary processes is more limited. Defoliation aims to eliminate these older leaves and rejuvenate the cannabis plant.

The benefits of proper defoliation

When done right, defoliation triggers a long list of benefits for the cannabis plant. Some of them include:

Larger yields

Defoliation has been proven to boost the yields you can get from your cannabis garden. There are two angles to this: the first revolves around the plant hormone ethylene, which is known to lower yields because of its ability to trigger aging processes within plant cells.

Per nature’s design, ethylene is found in higher concentrations in older leaves and flowers, such as those at the lower ends of the cannabis plant. Defoliation effectively nips these leaves and flowers, triggering higher yields for the plant.

The second angle revolves around defoliation’s ability to increase the exposure of leaves to sunlight and air, which directly stimulates more photosynthesis, better growth and larger yields by harvest time.

Efficient light absorption

Plant leaves and flowers need direct light for a number of reasons, but mainly photosynthesis, faster growth and formation of resins. Defoliation helps clear overgrown sections of the plant by eliminating unnecessary leaves and exposing others to light.

When choosing leaves to spare, experts recommend that you give priority to newer, younger leaves because older, larger leaves (usually located lower down the plant) carry out less and less photosynthesis regardless of the amount of light received.

Note: If the cannabis plants are so close together in a small garden, you might need to nip a lot more leaves per plant for them to access any light. Just don’t overdo it because too much leaf loss directly affects plant growth.

Better ventilation

For cannabis plants, increased growth also means more leaves everywhere. When no defoliation is done for a long time, the lower and inner sections of the plant see their air circulation cut off by the many leaves around foliage, which is detrimental for growth as there is limited gas exchange via the stomata in the leaf.

Defoliation helps avert disaster here, especially if some of the bigger leaves are cut off and sections with more leaves are trimmed to allow air flow into other sections of the plant.

Lower risk of bacteria

In addition to pests and fungal infections, bacteria are another major hazard to watch out for when growing cannabis plants. Defoliation can help lower bacterial infections, thanks to its ability to improve light absorption and increase airflow toward the plant.

These effects are direct triggers for increased chlorophyll and more photosynthesis, which in turn result in increased leaf concentrations of phenols such as resveratrol and apigenin. Both compounds happen to have natural immunity boosting abilities, so they help the cannabis plant combat bacterial infections.

Source?