Should I “top” an auto-flowering cannabis plant?

Updated Nov 15, 2019

by Nebula Haze


Yes, you can top auto-flowering plants that are growing fast and healthy as long as they haven’t started making buds yet. I top auto-flowering plants around week 3. If it hasn’t grown at least 4-5 nodes (pairs of “real” leaves) by the end of week 3, it may not be growing fast enough to handle topping without getting stunted. Read on to learn more!


When it comes to growing auto-flowering cannabis strains, there is a lot of controversy about whether they are compatible with the cannabis training technique known as topping (cutting off the tip of the plant while its young).

Some growers say you should never top an auto-flowering plant, while others claim they can top their autos without a problem. How can there be such a big difference in results between different growers? Well, here’s the thing about topping autos….

Topping auto-flowering cannabis strains is often not recommended because they’re on a tight schedule and may not recover in time, but it can be done if your plant is growing fast enough during the first few weeks of growth.

Auto-flowering marijuana strains have a short timeline, which is why it's usually recommended not to top them

Auto-flowering cannabis plants are on a tight schedule! Most auto-flowering strains start flowering at 3-4 weeks, and have pretty much stop growing vegetatively by the time they’re 6-7 weeks old. It’s difficult or impossible to change the strain’s individual time schedule. It still takes a few more weeks until buds are ready for harvest, but in that time an auto-flowering plant generally won’t be growing new leaves and stems.

An auto-flowering plant is “full size” at just 6-7 weeks from seed! For example, these autos are 6 weeks old, which means they won’t get any bigger even though buds are still fattening and harvest is several weeks away!


Auto-flowering cannabis plants at week 6 - a view from the side

So if you top your auto-flowering cannabis plant when it’s young and it gets shocked for weeks, that means your plant only has fewer weeks in total to grow if you think about it. A small cannabis plant is going to yield a lot less. This is why many growers say to never to top your autos. You want a big plant instead of a small plant if possible. You need long colas to get the best yields from cannabis plants.

For a first-time grower of autos, it can be easy to stress the plant and stunt its growth for all kinds of regular reasons. Topping just throws another factor into the equation!

A stunted autoflower won’t produce much bud because it never gets big!

Example of a stunted auto-flowering cannabis plant - it started flowering before it got any bigger than this

If an auto-flowering cannabis plant grows slowly when they’re young, they stay tiny their whole life. Even though the above grower took really great care of this plant from here on, and got pretty good yields for such a small plant, he would have gotten way better yields if the plant had grown fast enough to get bigger.

An auto that grows big can yield a lot, even if it’s untrained like this one!

This auto-flowering cannabis plant was allowed to get much bigger, which allowed it to produce much greater yields

You couldn’t yield all that bud on a small plant no matter how it was trained!

And on top of all that, you don’t need to top your plants to get multiple tops. These autos were grown with just LST/bending and they all have multiple tops.

Topping isn’t necessary to get multiple colas with autos!

3 Auto-flowering marijuana plants trained to grow with multiple tops using just LST and bending - no topping!
Here’s the full grow journal for those autos if you want to check it out!

All that being said, sometimes topping an auto does go well. If you have a really healthy, fast-growing plant, topping it may not stunt it at all.

In some situations, topping may produce a better structure and increase yields!

So it’s not a matter of whether you should or shouldn’t top autos, as much as a matter of evaluating your situation and deciding if the reward is worth the risk for you!

When it’s Not Recommended to Top Auto-Flowering Plants

  • it’s your first grow
  • plant has deficiencies
  • plant is drooping
  • plant is growing slowly
  • plant is more than 3-4 weeks old or has started flowering
  • plant has not grown at least 4-5 nodes (sets of serrated leaves) by the end of week 3

When It’s Okay to Top Auto-Flowering Plants

  • plant is green and healthy
  • plant is growing quickly (you’re seeing brand new leaves every single day)
  • plant has grown at least 4-5 nodes (pairs of “real” leaves) by the end of week 3 – this isn’t a hard and fast rule, it just demonstrates that your plant is growing fast enough to handle being topped without stunting.
  • to actually top the auto, I pinch off the top set of leaves. It’s a good idea to remove as little plant as possible so as not to stunt its growth.

Only cut off the tip when topping an auto!

Diagram example - how to top an auto-flowering cannabis plant

Don’t cut off more than this when topping an auto-flowering marijuana plant

Never take off more than this when topping auto marijuana plants!

Conclusion: Topping an auto-flowering strain can be good or bad, depending on how it’s done

There are times when topping an auto-flowering marijuana plant makes sense, and times when it doesn’t. For a lot of growers, topping their auto may reduce their yields by stunting their plant overall. But for more experienced or successful growers, topping is a suitable training tactic!

Use the guidelines in this article to decide what’s right for you, and when in doubt use LST/bending instead because it can accomplish nearly the same thing without as much a chance of stunting your plant!

I hope this information helps guide you to make the right decision for your own auto-flowering marijuana garden!

Learn more about training auto-flowering strains



Jump to…

Auto-Flowering Strains vs Photoperiod Strains

Cannabis Plant Training for Bigger Yields

Where Can I Buy Seeds That Deliver to My Country?

5 Ways to Increase Indoor Yields



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