Plant shaping and training techniques
How to easily influence the shape of plants so you get the most out of them? With proper shaping you can harvest a plentiful yield even from a smaller space. We have compiled an overview of the most popular techniques used by both hobby growers and professional cultivators.
Experienced growers know that yield is not just about genetics or nutrition. The plant structure also plays a decisive role. Techniques such as supercropping, schwazzing or ScrOG allow you to purposefully modify growth, increase light efficiency and achieve significantly better results. Let’s recall how they work and when to use them.
Topping: Trimming the tops
A basic technique every grower should master. It consists of simply cutting off the tops of plants so that branching occurs in their place. Most growers top their plants for the first time once they have three tiers of true leaves, except for some specific growing styles (e.g., SoG). After topping, two new tops will grow from the main stem and four side branches one tier lower will grow faster. The plant should then have six new tops at roughly the same height.
You can top multiple times, but only during the vegetative (growth) phase. After switching to flowering you would only be removing future buds by cutting the tops. The more times you top, the bushier the plants will become.
Fimming: Pinching the tops
A pinching technique said to have originated by accident, which is why its English name is F* I Missed. Fimming involves cutting the apical shoots so that roughly 20% of the top remains on the plant. When successfully pinched, the plant produces four or more new tops very close together instead of two. The result is short plants with buds clustered together and high yields.
Defoliation: Removing leaves
Leaves are where photosynthesis takes place and are indispensable for plants. Still, most growers regularly defoliate their charges. Usually this is done to improve canopy penetration for light and air, which helps prevent mold and increases yields. But you must not overdo defoliation, and you need to know when and which leaves to remove.
During the vegetative phase: There is a common myth among growers that removing large leaves helps plants redirect energy into creating new tops. In reality this slows growth. Therefore during the growth phase remove only leaves that shade lower branches, grow inward toward the plant, touch the substrate, or are in the shade. Also remove yellowing or dried leaves.
During flowering: Although plants still need leaves while flowering, careful defoliation helps create a better microclimate and prevents mold. Especially in indoor cultivation it’s a good idea to remove leaves from the lowest tiers where light doesn’t reach. Likewise remove larger leaves that shade ripening buds. As harvest approaches, regularly remove yellowing and dying leaves.
Schwazzing: Extreme defoliation
Leaves that receive enough light photosynthesize and create carbon, which is the source of sugars for other parts of the plant. On the other hand, shaded leaves store carbon and photosynthesize only minimally. Therefore removing shaded leaves helps plants better use available carbon and leads to higher yields.
Schwazzing is a method popularized by J. Haupt in the book “Three A Light,” consisting of repeated extreme defoliation during the first three weeks of flowering. The result is shorter plants with long buds, even on lower branches.
How to do it: On the first day of flowering remove all large (fan) leaves. Not only will this increase canopy permeability, but it will force plants to focus on developing new leaves instead of elongating stems, keeping them more compact and preventing stretching. Remember that by removing large leaves your plants lose a significant nutrient reserve. During the following ten days increase nutrient doses by about 20% with a formula higher in phosphorus and potassium (bloom recipe).
Perform the second defoliation on day 20 of the flowering phase and again remove only the large leaves. Be careful not to damage emerging flowers. By the third week of flowering the plant has already passed the stem elongation phase and thanks to the first pruning the buds should be growing close together. After the second pruning the flowers will develop close to each other and the result will be long buds. One advantage of schwazzing is that, unlike traditional methods, there is no need to trim the lower branches because they will also receive enough light without leaves and produce nice buds.
ScrOG: Weaving into screens
Screen of Green (ScrOG) is a technique of shaping plants into a horizontal plane using a net or grid. This has countless advantages, especially for indoor cultivation under artificial lights. If you leave your plants unchecked, they will always grow more vertically than horizontally. The main stem will be too close to the grow light, while the tops in the lower tiers will receive little light. The goal of weaving into a screen is to create a uniform surface of tops, all receiving maximum energy from the lights.
How to do it: Place the support net 20–30 cm above the base of the plants. Start weaving the tops as soon as they grow 5 centimeters above the net holes. Gradually guide the main branches in all directions and once most of the net is filled, switch to flowering and continue weaving for the next two to three weeks until full bloom and the plants stop stretching.
LST: Bending stems
LST (Low Stress Training) is a gentle shaping method in which branches are slowly bent and tied down. Bending stems can be used in many ways, from spreading the canopy and exposing lower branches to light to training photogenic miniature plants grown in controlled environments. Bending can also correct overgrown plants in the early flowering stage.
How to do it: Using soft tie wire, strings or plastic clips start bending the main stem and later the side branches outward from the center of the plant. This exposes more leaf surface to light and encourages the growth of new shoots. Perform LST only during the vegetative phase and in the first weeks of flowering while stems are still flexible.
Supercropping: Breaking stems
Supercropping is a technique where you deliberately damage the internal structure of a stem so that it bends without snapping. The plant responds to stress by strengthening the damaged area and growing more vigorously in other parts. Breaking stems is an advanced technique and requires a sure hand.
How to do it: Choose a flexible stem in the growth phase and gently squeeze and massage it between your fingers until it gives slightly. Then bend the shoot in the desired direction. If the branch won’t stay in the new position, tie or prop it. Within a few days the plant will form swollen joints at the damaged stem.
Shaping is a path to better results without having to change nutrition or lighting. Start with simple techniques such as topping or LST, and gradually discover what suits your plants best.
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