GROWING

Topping Cannabis: How and When to Top Your Plants

One snip at the right time turns a single tall cola into a bushier plant that fits your grow tent, as long as you don't do it at the wrong moment.

BY CosechaLibre Editorial4 MIN READ

Topping is cutting off the main growing tip of a cannabis plant during the vegetative stage so it grows bushier instead of taller. Do it in veg, roughly 5 to 10 days before you switch the lights to a flowering schedule, never once flowering has started. Thanks to indoor grows and autoflowers you can grow year-round, and topping is a simple, reliable way to make the most of a small indoor space.

Keep in mind: you always top before flowering.

-Start this kind of pruning 5 to 10 days before switching to the flowering light schedule.

-You'll need trimming scissors disinfected with alcohol to make the cuts.
-Snip off the small tip at the very top of the plant.
-The yield gets spread out across the secondary branches.
-It's mainly about making the most of your space.
-Great for keeping mother plants in shape.

A plant's vertical growth is driven by a hormone called auxin. When you cut the tip, the plant stops producing it there and pushes its growth out sideways instead.

The vegetative stage is the ideal time to top because it gives the plant time to recover. Every cut is a stress, and for that stress to work in your favor, timing is everything.

Top during flowering and you can wreck the plant. New shoots take about 7 to 10 days to come in, so wait two weeks before making another cut to give the plant time to bounce back.

Where to top a cannabis plant

When should you not top cannabis?

Topping is a technique growers use on all kinds of plants, cannabis included, to encourage bushier growth and keep height in check. But there are situations where you shouldn't top. Here are a few:

Very early growth: In the plant's earliest stages, it's better to hold off on topping. At this point the plant needs to build a strong root system and healthy foliage before any major pruning.
Young or weak plants: If the plant is young or weakened for any reason, like disease, stress or harsh environmental conditions, skip the topping. The plant needs all its energy and resources to recover and get stronger.
Autoflowers: Autoflowers have a shorter life cycle and grow faster than photoperiod strains. As a rule, topping autoflowers isn't recommended, since it can throw off their growth rhythm and cut your yield.
Late flowering: During flowering, steer clear of topping, since it causes unnecessary stress and can hurt flower and resin production.

How many times can you top a cannabis plant?

In general, you can top a plant several times over its life cycle, but there are a few key things to consider. Topping usually happens during the vegetative stage, when the plant is building its structure and foliage and can respond to and recover from the cut best. Still, always check the plant's health and vigor before topping again. If it shows signs of weakness, stress or disease, hold off and let it recover and get stronger. With autoflowers, top carefully and early, since they have a shorter life cycle and grow faster. Keep it early and limited on autos to avoid delaying their development and flower production. And remember, you don't top during flowering, since it causes unnecessary stress and can hurt bud development and resin production. Every plant and strain has its own needs and tolerance, so do your homework on your specific plants before you start cutting.

Diagram showing where to cut when topping cannabis

When is the best time to top cannabis?

Topping is usually done during the vegetative stage. The sweet spot is once the plant has at least 3 to 4 pairs of true leaves (nodes) and has reached a decent height. At that point it can respond and recover quickly from the cut, which encourages bushier growth and stronger side branches. Every plant is different and may have its own ideal timing, so watching how it's growing and how healthy it looks will help you pick the right moment. And always use sharp, disinfected tools and proper technique to avoid unnecessary damage.

What happens if you top a plant wrong?

Botch the topping and your plant can pay for it. A bad cut can put the plant under too much stress, slowing or stalling its growth. Cut off too much of the top and you can cause irreversible tissue damage that hurts its health and development. Poor topping can also throw the plant's growth out of balance, with side branches developing unevenly and leaving you with a lopsided plant and weak structure. Topping takes care and proper technique. If you don't have the experience or confidence yet, get some guidance from experts or seasoned growers first.