Can You Defoliate Autoflowers? Grow Questions Answered

9 August 2021

A grower asks: “I have a Gelato Auto in my 2’x2’ grow tent, and she is 2 weeks into flowering, very bushy and quite tall. Can you defoliate autoflowers? I have already removed a few lower fan leaves but I think she needs a more thorough haircut in the middle.”

You certainly can defoliate autoflowers if this will improve light penetration and air movement inside the canopy. It’s safest to do selective defoliation — when you take off only the bare minimum of leaves. Heavy defoliation is possible with stronger autoflower genetics, but make sure you follow our guidelines.

Can You Defoliate Autoflowers in Flower?

In the situation described above, the grower can and probably should defoliate his autoflower because she’s tall and bushy. First of all, this means she’s healthy and can take some abuse without skipping a beat. Second, her being tall means that lower bud sites are probably too far from the light. If they are also shaded by fan leaves, they’ll never amount to anything worthwhile.

You either remove the fan leaves shading the lower buds or—if the distance from the light is too great—pluck off those lower buds as well. It’s better to make the lower portion of the bush completely barren and channel the energy to the tops.

the bottom part of an autoflower defoliated in week 6
Strawberry Banana Auto by FastBuds ‘lollipopped’ in week 6 from seed (right before the transition to flowering). © Growdiaries

If you need to do a lot of defoliation to expose every promising bud site to light, make sure you remove only mature leaves that wouldn’t grow any more. Also defoliate no more than one third of all the fan leaves in one go and wait at least a week before the next defoliation session. Usually, it’s safe to trim your plant in this manner until she stops her flowering stretch.

should i defoliate autoflowers in flower; week 2 of flowering, heavy defoliation
Purple Punch Auto by FastBuds on days 41 and 44 (the second week of flowering). © Growdiaries

After that—in late flowering—defoliation usually does more harm than good. You may admire the look of all those exposed frosty colas, but they would probably yield more if you didn’t trim them in late flower.

Related Post  Autoflower Defoliation Sweet Spot: When and How Much?

Do You Defoliate Autoflowers in Veg?

The question of how to defoliate autoflowers in the vegetative phase is also a common one. Again, it’s best to be very selective about it. Fan leaves are especially important in veg because they are solar panels that convert light into energy. They also store lots of nutrients that can be transported to other parts of the plant and used there.

So think twice about removing any of the fan leaves during veg. Here’s a quick checklist for you:

  1. Are fan leaves blocking light from lower side shoots?
  2. Will those side shoots grow more vigorously if they are not shaded?
  3. Is the canopy too dense to be properly ventilated?If you answer ‘yes’ to any of those questions, then maybe you should defoliate your autoflower by removing a leaf or two at a time.

If you answer ‘yes’ to any of those questions, then maybe you should defoliate your autoflower by removing a leaf or two at a time.

Some growers also apply high-stress training techniques, such as topping, on their autoflowers, and, as a result, they turn into a wide bush with a great number of flowering tops. Those tops are usually close together, and the foliage between them makes the bush impenetrable to light and very poorly ventilated. In this case, heavy defoliation before the start of flowering is almost a must.

how to defoliate autoflower in veg in week 6
Cream Cookies Auto by FastBuds defoliated rather heavily in week 6 from seed (in the pre-flowering stage). © Growdiaries

Just make sure the transition to flowering hasn’t started already. Otherwise, it’s too late to heavily defoliate now. You don’t want to subject your plant to even more stress at this point. So give her a week to begin flowering for real and then defoliate.

We hope this answers your questions. And if you have more, please refer to our more comprehensive article on autoflower defoliation.

All images in this post were taken from GrowDiaries, the world’s largest weed growing community.