Plant training is an effective set of techniques for managing the size of your canopy and increasing cannabis yield (if you do it right). Of the variety of plant training methods, some techniques are considered low-stress training (LST), while other methods are considered high-stress training (HST).
Pruning Marijuana Complete Guide
By manipulating cannabis branches through bending or pruning, auxins (growth hormone) are redistributed throughout the cannabis plant, which can lead to a larger yield. This article will walk you through commonly used plant training methods and help you avoid over-pruning.
Benefits of Plant Training
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Breaking the apical dominance - Cannabis plants send most of their growth energy to the highest point of the plant. By topping, bending, or pinching branches, the plant's apical (tallest) point is removed or lowered to a height equal to the other branch tips. These actions break the apical dominance and redistribute auxin to other parts of the plant, which can improve overall marijuana yield.
- Level canopy - When all of the branch tips are at the same height, they will receive an even distribution of auxins, encouraging even growth. As growers achieve a level canopy, they can place the grow light closer to the majority of bud sites, increasing light intensity. Both of these factors improve your chances of increasing your marijuana plant yield.
- Controlling height - If growers have a variety of marijuana strains in the tent, some strains may grow taller and faster than the rest. In other cases, a cannabis plant may grow too tall and touch the grow light. Using either LST or HST methods, growers can keep their garden space under control through bending or pruning cannabis.
- Maximizing space - Just as these techniques can be used to control wild growth, they can also be used to maximize available space. The LST techniques of scrogging and bending branches can help widen the footprint of a cannabis plant. The more space used within the tent, the higher the marijuana yield.
Plant modification techniques such as pruning, defoliating, and trimming can also beneficial. Increased airflow within the canopy after the process of defoliation can reduce instances of powdery mildew (PM). Removing a select number of fan leaves can also lead to better light penetration, which leads to larger cannabis buds. Increased light penetration and removing lower lateral branches will also lessen larfy, airy buds sent to the trimmer.
High-Stress Training vs Low-Stress Training
As the name implies, one group of techniques creates more stress on the plant. Growers will need to allow plants time to recover. Training should be performed when the plant is healthy and recently watered or fed with a nutrient solution. Recovery times range from 24 hours to a week in some cases. Recovery is monitored by the amount of new growth. The right amount of stress can cause growth to stall momentarily. Too much stress and the growth can stall completely.
In the seedling stage, HST is not recommended. The first plant training techniques are generally performed after the marijuana plant has 5-6 nodes. By this time, the root zone has begun to establish itself. The larger the root system, the quicker the recovery.
The majority of plant training is performed in the vegetative stage. New growth is easier to bend and manipulate. As the plant ages, stems get woody and harder to work with. During the flowering stage, it is common for growers to lightly prune, defoliate, and do some bending of branches under a SCROG net, but you do risk snapping branches.
Not every marijuana strain responds well to plant training or pruning, but most do, which is why these techniques are regularly used to increase yield. Many methods can be used in combination with each other. We recommend growers start by practicing LST before moving on to HST.
Low-Stress Training for Increasing Marijuana Yield
LST is achieved by bending branches. This cannabis pruning method occurs early in the vegetative stage and is repeated as the plant grows. Upper branches and occasionally the upper portions of the main stem are bent down to a level that is even with the lateral branches. If you remember, this redistributes the growth energy to create numerous apical buds instead of just one big kola.
Branches are easier to bend in the early vegetative stage when the gauge of the branch is smaller. Bending branches is generally achieved by one of three methods; wire, clips, or a SCROG net. Branches can be pulled lower and attached to the side of the potting container using rubber-coated or plastic-coated wire. If the grow pot does not have available attachment points, you can use binder clips as an anchor to attach your gardening wire.
Training clips are another option. These specific clips are made of plastic and can be 3D printed at home. The clips attach to a branch and force it to bend and grow in a predetermined shape. If growers choose to use these clips, it is best to start early in the vegetative stage to shape the plant effectively.
Other popular forms of LST: pruning upper fan leaves and twisting stems. These forms of LST are effective at slowing down growth momentarily, giving lower branches time to catch up to the top growth and create a level canopy. Only remove leaves without trichome coverage.
Stem twisting involves firmly grabbing a mature branch (but not crushing) with your fingers and thumbs and rotating them gently in opposite directions. Only a quarter turn is needed, and you should feel, and sometimes hear, a pop.
If you have been exploring the internet looking at different cannabis grows, you’ve likely seen some with a square grid net over the canopy. These are called SCROG nets, which allow cultivators to use the style of growing known as “screen of green” (SCROG).
As cannabis branches grow above the level of the SCROG net, gardeners gently bend them under the net. Doing so will cause them to grow laterally. This method maximizes the potential of the available square footage and seeks to gain more yield at harvest. Growers with longer vegetative periods will use two or three layers of SCROG net to build a bushier, level canopy cannabis plant.
**Pro tip - When bending thicker, woodier stems, rub the stem slowly between your fingers back and forth. This massaging action weakens the cellular walls and will make the branch easier to bend without snapping.
High-Stress Training for Marijuana Yield
These options almost always involve pruning the plant. Topping, fimming, and sea of green (SOG) are amongst the widest-used forms of HST. Super cropping is a technique that doesn’t prune the plant, but the cellular walls are impacted. This group of methods requires a recovery period before growth resumes.
The most common form of HST is topping. It requires only scissors. To top, wait until your marijuana plant reaches 5-6 nodes of growth, then cut an inch above the node space you want your top branches to grow from. Essentially, you are removing the head and will not have a big top kola. This redistributes auxins, and lower branches will grow faster to achieve an even canopy.
The FIM technique is similar to topping, but the cut is made closer to the node, resulting in four top branches instead of two. As the new growth emerges from the top of the plant, there will be a small opening between the petiole of the new leaf and the newest emerging leaf cluster. By cutting just above the base, in the middle of the small opening, you will top the plant but leave the newest nodes intact. They will grow even with the lateral branches on the node below, creating four tops.
Sea of green (SOG) is the practice of removing all lateral branches. This results in a single cola, which gets 100% of the growth energy. Cultivators using SOG will grow dozens of plants in small containers, tightly packed for maximum yield. A benefit of this style is you can have a large variety of plants in a small space. The drawback to SOG is that you need a lot of plants to equal the same yield as a few bushy plants.
Super cropping is a popular plant training technique as well. New growers may shy away from this method because it involves weakening the cellular walls until the branch can no longer support its weight. The same technique of massaging the branch we used to bend branches is applied, but this method takes it to the extreme. As the branch recovers and the lateral branches below gain height, the super-cropped branch will form a knot or an L-shaped elbow and continue its vertical growth.
Mainlining is an advanced growing technique that involves multiple toppings of the cannabis plant. This cannabis cultivation technique is most effective when done from seed and can lead to an exceptional yield. The drawback of this plant training technique is that the recovery and growth durations add considerable time in the veg stage. This technique combines HST topping with LST bending and tying down branches, which leads to numerous colas from a single seedling.
Pruning lower branches that receive minimal light reduces the workload at harvest time. Trimming marijuana can take an extended period of time. Do yourself a favor and remove the headache of trimming larfy buds by pruning those branches. Drying your cannabis is also quicker with less materials on the crop. Large fan leaves without trichomes should be removed before harvesting and drying unless you are drying in a very low-humidity climate.
Pruning Marijuana: Seed vs Clone Considerations
The way growers train plants that originate as seeds or a clone can sometimes differ. Cannabis seeds produce a seedling that grows with symmetrical branching. In the seedling stage, the first few nodes have little space between them in most cases, but this is strain dependent. Topping or fimming plants started from cannabis seeds produce symmetrical top branching, which can result in bushier plants and a larger yield.
Clones are cuttings from a branch on the mother plant. As lateral branches grow, they often lose symmetrical nodal spacing, resulting in uneven branches. With LST techniques, gardeners can create an even canopy. Once the plant is in the mid-vegetative stage, HST techniques like topping and super cropping can be used as well to level the canopy of clones.
Cannabis Pruning Final Thoughts
Many professional and home cultivators use LST and HST methods in the garden. Topping a plant (HST) and bending the top branches downward (LST) is a popular combination. Growers will also use defoliation and pruning of lower branches together. Super cropping compliments all of these methods as well. Use the various techniques to sculpt marijuana plants to your wishes.
There are many space-related reasons to train your plant. When space is no issue, growers look for ways to increase their cannabis yield. Training in the early veg stage can give growers an increased opportunity for a larger yield by having more bud sites directly exposed to the grow light.
When cutting your marijuana plant, use a sterile and sharp pair of pruning scissors. Good IPM practices suggest that cultivators sterilize the scissors between each plant to avoid the possible transmission of viroids or pathogens via the plant sap on the scissor blades. It would also be wise to change disposable gloves for each plant handled.
New growers rest assured; when pruning lower branches, you are removing bud sites, but you're also redistributing that growth energy to other parts of the plant. The same can be said when gardeners prune the top of the cannabis plant, breaking the apical dominance. Both of these actions can increase yield.
Above all, don’t be scared, but don’t try every technique at once. Give the plant time to recover. If you accidentally snap or split a branch, don’t panic. Use some tape and splints, if necessary, to support the branch. Healthy plants will recover quickly from breaks if the plant tissue is still partially connected.
Follow these plant training techniques to realize a better yield, maximize your cultivation area, and keep unruly marijuana plants under control. Happy gardening!
FAQs about Pruning Marijuana Techniques
Why rubber-coated wire for LST?
If using regular wire, as the branch thickens, the exposed wire can cut into the branch causing damage. The connection doesn’t need to be tight; it just needs to be secure enough to anchor the branch down.
How late in the stages of a weed plant should I prune?
Most plant training should be done before flipping your marijuana plant to the flowering stage. To thin the plant out in the mid-flowering stage, some growers will remove small auxiliary branches on the lower lateral branches. Defoliation is also common during the flowering stage to improve airflow and light intensity within the canopy.
Can I top autoflowering cannabis?
Stress is one of the potential triggers of autoflowering strains, resulting in smaller plants. Autoflowering plants don’t provide time to recover; they are on a predetermined vegetative schedule. Do not perform HST techniques, but some autoflower growers use the LST method of bending branches or using training clips with positive results.
Should I trim fan leaves during flowering?
Yes, defoliation (removal of fan leaves) is useful so that developing buds get as much light as possible and the canopy has adequate airflow. A good rule of thumb is to remove any fan leaves that are shading bud sites or any fan leaves that are shaded themselves.
Should I cut off big fan leaves?
It depends on how many leaves your plant has and where she is at in her growth cycle. You will always want to have some fan leaves as these are the plant’s solar panels that enable her to photosynthesize. Only remove leaves when they are blocking bud sites or if the leaves are shaded.
Will a weed plant grow back after harvest?
No. Cannabis is an annual crop. After harvest you will need to start over with germination of new seeds or clones.
Why is pruning good for plants?
Pruning, or cutting off parts of a plant, is a useful technique to redirect where the plant is putting its energy.
Can you get high from trimming marijuana?
No, you need to ingest cannabinoids to feel high from weed. But any cannabis trimmer that has hand-trimmed knows that your fingers get covered in sticky hash that some choose to enjoy after they are done trimming.