Effect of Defoliation on Yield - Skywalker OG indoor scrog

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OscarLaGrouch

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Summary
Preliminary research of the internet on the effect of defoliation on Cannabis Sativa yields results in little definitive information. The only way to determine if defoliation has a positive, negative or neutral effect on yield is to do a side-by-side comparison. This experiment will do just that. Controlling for all other variables, the only experimental variable will be the methodical removal of fan leaves that effectively shade bud sites. The goal is to determine if allowing artificial light to reach these sites provides the extra energy to increase flower size. Alternatively, it may be determined that removal of leaves has a hormonal effect on plants that may or may not be deleterious to increased yields.

Background
Researcher has a B.S., in Botany from a University of California and has been growing for five years continuously in an indoor environment.

Environment
Sealed-air room is maintained at 79-83 degrees until week seven of flower where it will be dropped to 75 degrees. Reservoir is maintained at 63%F. Humidity ranges from 55-68% RH. Humidity will be dropped in week 7 to under 55% RH Auto-irrigation with drain-to-waste. Four Ushio HPS bulbs are 24" from the canopy. Plants are topped and supercropped into a scrog.

Materials
RO water
Heavy 16 nutrients (full line)
50/50 coco/perlite
Mykos beneficials mixed into medium and added weekly by top dressing
Protekt Silica
MagiCal
Bio-Cozyme
CannaZyme
Eagle 20
Dutch Master reverse
CO2
dehumidifier
drain-to-waste auto irrigation
4 x 1KW HPS bulbs over 2 4x8' trays

Procedure
36 Skywalker OG clones were obtained from Progressive Options, a reputable genetics farm in Los Angeles. All plants are clones taken from the same mother. All plants have been maintained in the identical environment as a group and have been or will be treated with the same materials. All plants will be fed the same nutrient regimen and have been planted in the same medium. The experimental variable will be applied to one 4x8 table while the other table will be untouched with regard to defoliation around bud sites. Defoliation/lollipopping below the scrog has been applied to both tables. All plants were topped in early veg at the fifth internode to encourage branching for the scrog growing method.
The experimental variable of defoliation will be applied only to fan leaves with a petiole that are directly shading at least one bud site. Defoliation will be applied beginning in the third week of flower and will continue as needed.
Weekly summaries of the experiment will be posted. Grow is expected to run up to ten weeks and will be flushed for one week at the end. Resulting flowers will be tested for potency, mold and pesticides by theWercShop.com and results posted here.

At harvest, plants from each table will be hung to dry directly under the table they were grown on. Each table will be hand-trimmed with identical methods and maintained separately from each other. Following a cure to 55% RH, each table will be weighed and the results posted here.

IMPORTANT: TROLLING WILL NOT BE TOLERATED.
All trolls will be blocked and all individuals quoting trolls into the thread will be blocked.
 

OscarLaGrouch

Well-Known Member
All clones are treated for PM, mites, gnats and light issues by the end of week 2 of flower. Beyond that no pesticides. Only exceptions are reverse wk 1 and perhaps wk 3 and 5 based on need. Mighty wash and/or sulphur burners will be used if needed as a non toxic way of dealing w fungal issues due to high RH. I dont wanna smoke residues so i do t spray them on flowers.
 

neo12345

Well-Known Member
Yeah i always defol but i wanna know how it affects each strain i grow.
So have you used this technique on Skywalker OG before? Are they 100% Sativa?

Can I ask what stage of the experiment you are at now, as you speak in past tense about some things? Do you have any pics?

As for the actual defoliation itself, am I right in thinking that you only defoliate from week 3 of flower? You didn't defoliate during veg? What percentage of leaves would you say you are taking in that first defoliation from the canopy, and then is it just a random removal from then onward?
 

Schwagstock

Active Member
scribing to this, very interested to see what the final outcome is. Do you have a personal opinion as to if you think it helps or not?
 

leyus

Member
Subbed, I love defoliation, previous indoor I defoliated all plants, this indoor just White Russian next grow I will do that to all plants again most likely. I would never do it outdoor since wind and animals and other things do it for me but indoor its awesome.
 

RedCarpetMatches

Well-Known Member
I tried defol several times. It was more like 'selective pruning'. I got very nice results. The one time I tried complete defoliation, I ended up with pussy willows...very dense pussy willows.
 

Cascadian

Well-Known Member
Subbed up, glad someone else is going to follow through with the experiment. I did a defoliation experiment recently with just one plant (only for my own curiosity). When I was reading up on it there was mention that starting defoliating in veg is a good idea to get the plant used to losing leaves and not stressing as much (reduce hermies). Just thought I would mention it, Thanks for running the experiment.
 
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