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Pruning and Training to Maximize Yield

Updated: Oct 7, 2021

The never-ending debates on cannabis gardening style are epitomized by the numerous techniques used to increase yield under artificial light. Even when two people learn the exact same technique in the same place, they will inevitably develop their own interpretation of that technique when it comes to pruning and training their plants. This is the fun part of growing and a great opportunity to finally vary from the “program” a little.

The first thing you must know is that there is nothing new under the sun - very few will ever come up with anything unique or novel to increase plant yield. The techniques described in this topic are as old as dirt, function the same across many varieties of plants (not just cannabis), and in another time, some of these techniques determined the wealth of one family versus another.

This is almost as true with modern indoor cannabis gardening, given the cost of electricity used by indoor lighting. The key to our success indoors is the ability to force our plants to acquire a certain stature, look, yield, and performance. There is no room for slackers under artificial light. Cutting half of the branches off of a cannabis plant is probably the most effective pruning or training anyone can do. So before you over think this topic, try to remember that.

Pruning and Topping

When we first transplant clones or seedlings into a one or two gallon container, we allow the plant to grow as wide and tall as that container before we engage in vigorous pruning. At that point, we simply cut off half of the plant or more by removing weak bottom branches (cutting with pruners flush to the stalk), and chopping the growing main stalk about 1/4-1/2" above a branch node. Wait for it to grow back up to size and see the difference. This second growth will have a thicker stalk, tighter nodes, tougher stature, and overall improvement that is easy on the eyes. It's just obvious. This technique is a little brutal. Don't be weak. Just do one plant and leave the other if you want to compare.

After the plant has grown back to size, we are ready to transplant into its final container of 5-20 gallons, depending on desired final size. This is our first opportunity to express some real individuality or personality in our skills. We continue to remove weak bottom branches and cut the (multiple) growing tops as we did earlier.

An interesting alternative to topping is called FIM ("Fuck, I Missed") which cuts just the growing tip, leaving the bottom 20% of the node on the plant. The result, if you get it just right, is multiple growing tops from a single node, rather than the two you would normally expect with topping. This technique takes some experience to get just right, and is sometimes called floribunding.

After the plant grows a few more nodes, we will observe the growth and keep topping or FIMming as desired. If extra vegetative time is required because of a full flowering room, you may even mow this plant down a foot or more, then let it regrow just like we did when it was younger. Each time this is done, there is incredible new and improved growth. One of the causes of this is an increased root mass to plant mass ratio. This another part of a simple philosophy that Uncle Pete has sprinkled throughout his formula that keeps our plants stronger right from the start, with thicker cell walls, nice fat stalks, a massive presence, and tougher in general.

Stress and Hormone Response

Stressing our plants is something that we hear many farmers discussing and is likely the most misinterpreted part of cannabis farming. Plant growth is catalyzed by several related hormonal reactions. The stimulus that begins a certain plant response or reaction is referred to as stress. That doesn’t mean the more we “hurt” or “break” our plants the better. It does explain why a plant responds in a very predictable and understandable way though. Understanding these basic hormones and the plant's responses is key to the program. Pay attention. This is not complicated at all.

  • Gravity Hormone: Plants know what's up and what's down due to a hormone. Not because their mama told them so. Anytime we bend or break a plant to fall against gravity it will try to go back up to survive because of this hormone.

  • Light Hormone: Cannabis grows towards the light. It doesn't get simpler than this.

  • Sex Hormone: Male or female or both (hermaphrodite) determines the flowers that grow.

  • Shock Hormone: Survival mode that causes a reduction in uptake and loss of yield.

These are laymen's terms made to be understood by everyone. Whether we are bending, twisting, tying, cutting, pruning, or FIMming, it is these hormonal responses which are at play and define the characteristics of our different cannabis strains. Mastering these techniques and understanding these basic responses is the experience which allows us to coerce each plant in our garden to grow and perform to its full potential.

Don’t be afraid to break some branches and learn some lessons. We have tied, bent, hung, cut, flipped, and flopped plants for so long that there is not much we haven't seen yet. Topsy-turvy tomato planters are a perfect example of plant hormonal responses being predictable and manipulated to our advantage. Don’t let the cannabis plant manipulate you. It is just a plant. We know you can win that battle.

Bending and Thinning to Maximize Canopy

My son loves to bend and twist his plants, while I like to cage and tie them to where I like them to be. If you hold a stalk in your hand and run your fingers up it, you can feel how it is tough and woody at the bottom and as you get towards the new growth it becomes soft and pliable. Somewhere in the middle is the snapping point. Being aware of these points and pressures is the key to a soft but firm touch in the garden. It becomes much more of a natural feel than a calculation. Even the best of us miscalculate from time to time and break a branch we meant to bend, but with some courage and experience you can really get a feel for exactly what you can force this plant to do. Once you find that in between spot between wood and soft tissue, pinch it, rub it a little as you pinch it, and soften it up by mashing it a little. Now you'll be able to bend that stem or stalk any direction it needs to grow. Put it where you want it and tie it there. It will repair itself and start new growth in the desired direction.

Thinning our plants is important as well. You should be able to see through your plants. If they are too thick and bushy, light and air will not get through and yield will suffer. You will also allow a protective home for pests and infections. Keeping light and air going through our plants is our natural defense to things like mites, mildew, and mold. In addition, spindly interior branches have poor yield and are more tedious to trim.

If we cut a branch or prune it, it generally splits into two.

We split or prune those two branches to get four.

We then turn four into eight... eight into 16...16 to 32...and 32 to 64.

You don't have to be a math wizard to calculate that 64 quarter ounces of cannabis is equivalent to one pound. So if you can force a plant to have 64 tops in a 5' x 5' area with at least 1000 watts of HID light beaming down, maintain a good environment, proper pH and nutrients, it is fairly simple to grow a one pound plant with proper pruning during vegetative growth.

Applying this very simple concept is exactly how Uncle Pete learned to grow two pound plants. It turns out you really only need about 32 tops to grow a one pound plant. The two-pounder is the new target! With today's double-ended HID lighting and the high quality bottled fertilizers manufactured by General Organics, anybody can grow like Uncle Pete. Especially if you follow the formulas described in the intermediate topics Optimizing Vegetative Growth and Optimizing Marijuana Flowering.


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