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How To Prune Cannabis Plants


If you’re growing cannabis plants, knowing how and when to prune them is a vital skill to have in your arsenal. In this article, we’ll look at how to prune cannabis plants, when to prune, and explain why you should prune.

What is Pruning?

Pruning is an integral part of cannabis cultivation, but is something of a divisive practice among growers due its high-stress nature. It’s the practice of defoliation, cutting away any dead leaves, damaged sections, or unproductive parts of your plants. Removing these will encourage healthier overall growth of your plants. The remaining leaves will receive more nutrients and light, meaning a generally sturdier plant with denser buds. While it’s arguable that pruning isn’t necessary, the pros (a more robust, healthier plant with a higher quality yield) certainly outweigh the cons (the effort of pruning your plants).

Why you should Prune your Cannabis Plants

Removing damaged parts of the plant, such as dead foliage, means it focuses all its energy on the essential areas, without unproductive features remaining there to suck energy. Pruning also improves the airflow throughout the plant, meaning more CO2, and can reduce the chance of pests and insects hiding among the foliage. Other benefits are more grower-specific – for example, if you’re growing in a small space, pruning keeps your plants a little more compact and makes the most of the room. This meanins your plants can flourish without obstruction.

Is Pruning the same as Trimming?

Pruning and trimming your cannabis plants may sound the same, but there are some differences. While both practices involve snipping off plant parts, they should be carried out for different reasons. Pruning is about removing problematic parts of your marijuana plants, and trimming is more of an aesthetic pursuit. Trimming is often carried out after harvest and will see you removing fan leaves and sugar leaves, allowing for a smoother smoke.

Different Pruning Techniques

There’s more than one way to skin a cannabis plant. There are three main techniques for pruning weed plants, although these specific styles are for experienced cannabis growers. If you’re a beginner reading this ahead/during your first grow, you can still prune your plants, but these pruning methods are a little more advanced.

Topping

Topping is a training technique that encourages your plant to grow a certain way. As you may imagine from the name, topping involves pruning the tip of the plant’s main stem. When you do this, the tip of the main stalk will grow back in a v-shape, eventually leading to two main colas. Another advantage of topping your weed plants is that it allows more light and air into the lower parts of the plant, promoting better growth.
Experienced cultivators suggest topping somewhere during the first month of vegetative growth when the plant should have developed between three and five nodes. The plant should be sufficiently resilient enough to recover from topping by this point.

cannabis defoliation guide

Fimming

Brilliantly, the ‘fim’ in fimming stands for “f**k, I missed!” – indicating an accident occurring during an attempt at topping where someone snipped too far. But some accidents are happy accidents, and fimming is as beneficial as topping – if not more. Fimming is carried out for the same reasons as topping but carries a bit more of a bonus. If carried out properly, fimming can lead to producing as many as four new colas at the top of your plant. It differs from topping in that while topping leads to greater horizontal growth, fimming ultimately leads to a taller plant.

When fimming, you cut about 75% of the main stem at the tip of the plant. As with topping, this should take place during the vegetative stage. Wait until your plant has developed between three and five nodes, and carefully snip. Exercise caution when timing the fimming process with your plants, as too early or too late could cause undue stress from which it’s harder to recover.

Lollipopping

Not nearly as delicious as it sounds. Put your tongue back in your mouth and grab your pruning shears. Lollipopping involves working at the bottom of the plant rather than the top. You’re aiming to remove lower branches that don’t receive adequate light exposure because these are detrimental to the overall growth and production of the rest of the plant. In addition, these areas produce smaller buds, so by lollipopping, you effectively ensure the production of better-quality buds come harvest time.

Lollipopping should be done later than topping and fimming, preferably around the second week of your plant’s flowering stage.

How To Prune Your Cannabis Plants

Think of it like a haircut – you wouldn’t just have at it with the scissors and hope for the best. That could lead to a mess. For that reason, if you’ve never tried to prune marijuana plants before, you might want to practice elsewhere rather than risk damage to your valuable weed crop. If you have any other plants or bushes, try pruning them for your first time, as mistakes are less likely to be devastating.
When you’re ready to try pruning your cannabis plants, inspect them a couple of weeks into vegetation. If you see a few leaves, get to work. Be careful, and start small. Once you’ve pruned, give your plants enough time to recover.

Tools

Use scissors or garden shears, and make sure they’re plenty sharp. Use isopropyl alcohol to clean the blades before and after each session. You want to sterilise your blades for this to avoid risk of any cross-contamination.

Inspect your plant for areas that require pruning. Dead leaves, excess growth, and sites that don’t receive enough light will be pretty easy to identify. Look to remove big stalks, and work your way down the plant, looking for any branches or leaves that appear unhealthy, dying or small. Use your snips to cut them away neatly. It’s essential to leave the larger fan leaves and only prune a bit at a time. Don’t attack everything in one session; work on a different area every week. Don’t remove loads of foliage each time, as this could cause additional stress to your plants. The result of this will be stunted growth.

TLC is necessary

After pruning, water your plants with nutrient-dense water to help them adapt to the stress. After roughly a week, you’ll see your plants have started to recover, plant growth has improved, and your plants are making new leaves.

Remember that, although pruning is a healthy addition to your plant’s care regimen, it doesn’t make for a substitute for good lighting, watering, and nutrient delivery. Look after your plants as you normally would, ensuring they are well fed and watered, looking out for nutrient deficiencies and any other issues.

When to Prune your Cannabis Plants

Pruning should be carried out during the vegetative stage before the plant is ready to flower. Ideally, your plants will be around 12 inches in height with several sets of leaves before you start pruning.

If you’re regularly pruning during the vegetative stage, take a break from the practice during the month before flowering. That way, your plants will have sufficient stress-free time to switch to flowering and will do so more successfully. Pruning at this stage can delay flowering or even prevent it entirely. Once flowering begins, a very light pruning is okay for maintenance, clipping away bigger leaves around bud sites to allow more air and sunlight (or grow light) to penetrate. Go sparingly during flowering.

If you’re growing autoflowering cannabis, avoid pruning your plants. They have a reduced growing time and will have less chance to recover from the stress of pruning.
As a final tip, don’t touch anything with trichomes on it! Those are valuable, so leave anything trichome-coated on your plant and remove only stalks and leaves.

What to do after Pruning

What you do with the clippings is entirely up to you, but you have options! Gather everything up, remove it from your grow area, and dispose of it to keep it nice and tidy. Or, if you want to get creative, you can use some healthy leaves and cuttings for recipes. These plant parts have cannabinoids like THC and can be brewed into a nice tea or even used to make edibles.

As for the plants themselves, as stated above, be sure to water and feed them after pruning. Pruning is a high-stress technique, so you should aid your plant’s recovery by giving the adequate amount of the correct nutrients for your chosen strain. Hop online and research your strain’s needs if you’re not sure.

Keep a close on your crop post-pruning to see that plants are recovering well, and avoid pruning again until your plant shows healthy new growth.

If carried out in a timely fashion and with care, pruning can improve the health of your plants, encourage new growth and increase yields come harvest time. Follow the guidelines, and you should have a trouble-free experience – and so will your weed plants.

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

Duncan Mathers