question time , question time get your note books out everyone , When do you trim up the bottom leaves out of the way - obvious after cloning but interested in your thinking on - when and in what stage early flower or before , as always meeks looking good and thanks for the info, nice play on the super bowl but i don't think i would of made the whole bowl after that bowl.....peace soser
There is no necessity to skirt (industry term for pruning lower leaves near the soil line) the plants at any point. Many growers do it for a couple of reasons, and depending on your motivation for doing it, there may be different timings you are shooting for. In the horticultural industry, we would only spend the man hours doing it before sleeving and packing the plants for shipping/sale to improve the plants aesthetic appearance for sale, not growth. But cannabis growers have shifted into growing much larger plants than normal greenhouse production plants and so things change a little bit.
The main reason a grower would want to do skirting of the plant in the vegetative stage would be if they were concerned with botrytis (disease). Leaving young leaves to sit in the media (contact with a wet surface) in combination with hand watering can result in minor leaf damage from the water force, which will make the plant vulnerable to the very opportunistic botrytis. It is important to recognize that if this is your concern, pruning the leaves with clean tools/hands and avoiding excessive tissue exposure when making cuts are critical precautions.
The second reason a grower might do leaf removal of lower canopy leaves would be at a time when they believe the leaves are past their prime maturity and beginning to decline in efficiency. As leaves develop they take a huge amount of energy, making young immature leaves a sink. Once they reach close to their mature size, they begin to produce more energy than they consume for growth and maintaining functionality, making them sources. Then, after a period of time (different for all plants) they are past their ideal maturity and begin to decline in efficiency. The process of senescence begins and the plant breaks down chlorophyll and other structures to recover nutrients and energy where it can before abscising the leaf. As this process takes place, a layer called the abscission layer forms between the base of the petiole (leaf stem) and the plant stem. You may have noticed how much easier it is to pull a leaf off a tree in the fall versus the spring or summer. . . this is because the abscission layer has formed in preparation for defoliation and winter dormancy. The ideal time to remove lower canopy leaves from your plant is when this layer begins to form, to minimize the wound/susceptibility to disease at the site of removal. With experience you will be able to feel the resistance of a leaf and tell whether or not it wants to come off or not based on resistance/presence of the abscission layer. If this is the reason you are removing leaves, it is important not to remove too many leaves at once, and to make sure you only remove leaves that are heavily obstructed from light or are past their ideal maturity and therefore functioning as sinks rather than sources of energy for the plant.
Another reason, as I just mentioned, is if lower leaves become so heavily obstructed from light (more common in indoor gardens with a fixed light source rather than a shifting natural sun) that they are no longer able to efficiently photosynthesize, they are still consuming energy through respiration and still consuming water and nutrients through transpiration. . . so they are worth removing to maximize your growth. If this is why you are doing leaf removal you may not be able to wait for an abscission layer to form if your plant is growing vigorously and you don't do LST or some other method of canopy spreading to allow light to penetrate deeper. You have two options for leaf removal technique. The classic prune at stem level (removing both the leaf blade and the leaf petiole), or just leaf blade removal. The concept behind removing just the leaf blade is that the plant will seal off the end of the petiole easier than a wound on the surface of the main stem, then after the plant realizes the leaf blade is gone (no more auxin being produced from that location), the plant will begin the natural abscission process (forming an abscission layer at the stem) and you can come back and remove the petiole later without create exposure for botrytis or other opportunistic diseases.
Lastly, many growers have problems controlling powdery mildew and other diseases like bud rot that will thrive if the air circulation is limited. If this is your concern, the decision of how many leaves and when to remove them must be made on a garden by garden basis, with anticipation of when you know the problem to occur for you. Many times, proper environmental control and plant spacing/structuring is the answer to removing these concerns, rather than pruning leaves after you notice the canopy is too thick.
Each strain will grow slightly differently, so there is no set in stone day, height, or leaf number to go by. . . only experience and good record keeping will help you dial this part of growing in. I hope this answer helps, I am sure you knew a bunch of what I mentioned already, but I thought it would help to include for the community at large.
mr.meeks .....I see you dont use any bloom boosters. Do you feel your plants respond better with a steady npk throughout flowering(yield) vs spiking p/k?
Also what range of temp/humidity/co2 do you plan to stay with in during flowering?
I have to say your thread is the most informative thread on the farm right now, really appreciate it.
That's correct DrKB. The only nutrient I would consider bumping up as flowering reached its peak would be nitrogen, but I currently do not. The spike in P during mid bloom might help promote more floral bud initiation, but the way most growers use a P/K boost they are just provoking a salt stress reaction (which may also promote more flowering). Every plant is different, so I can't say positively one way or another that cannabis does or doesn't respond well to a P/K spike. . . but from what I know, most plants are not fertilized this way to encourage the boost in flowering that growers are hoping for.
I am currently running 64-65F nights and 75-77F days with as high a humidity as I can get at the moment. . . running around 57%RH this week, but preferably I would be around 75-80% for veg, and then in the 65-70% range for early and mid flowering, than I drop down to 60% for late flowering to avoid disease risk. I usually bump my temps up to 66-67F nights and 78-80F days during peak flowering
(especially if I have increased my nutrient ppms for peak flowering growth or if my canopy is closer than 24" from the bulb), and then drop back down to where I am now before they finish.
I actually haven't been augmenting my CO2 since last spring. . . there is a gas water heater in the corner of the grow room for the attached house and the ppms of CO2 tend to float around 450 when I'm not in the room. If I was feeling motivated and rich I would refill my propane tank and get the CO2 generator going again. . . but my results haven't demanded it, so I haven't refilled it since the last time it went empty.
800-1000ppm is all that is needed if you do want to augment your CO2, and it is most important during the early morning, before your room is hot, when you may not be using cooling fans, which refresh your CO2 as they exchange air with the outside environment.
Thanks for taking the time to read the information that comes out in my threads, it is a two sided process that relies on reader participation from people like you!
-Meeks
