Nebula’s 3-Step Defoliation Tutorial (2020)

Published Feb 01, 2020

by Nebula Haze

I’ve already published a few cannabis defoliation tutorials, but this one is different.

It’s short, sweet, and to the point. You can use it on ANY plant in any setup, including autoflowering strains. As long as you follow the 3 steps, you won’t take any risks, and you will get great results.

Defoliation is the process of strategically removing leaves from your plant so that it grows in a way that’s more optimal for an indoor cannabis grower.

Defoliation means strategically removing leaves from your cannabis plant. This article focuses on defoliation in the flowering stage.

Example of removing a cannabis leaf - when defoliating, always avoid damaging the growth tip and the bud site!

Quick defoliation example: This plant is at week 3 of the flowering stage (3 weeks of a 12/12 light schedule). Light and air are not getting into the plant.

Example of a cannabis plant 3 weeks into the flowering stage - before defoliation

Post-defoliation – never defoliate more than this unless you already have experience with defoliation!

The plant was left alone after that. Here is the result at harvest

White Rhino plant grown in a hydroponic setupNotice how there are no small or airy buds on the entire plant

And lots of huge ones

Let me explain what’s going on here and how to do this yourself.

What defoliation does if you follow these instructions:

  • Healthier plants – Defoliation helps reduce the chance of bud rot or white powdery mildew on a plant that tends to grow bushy. This tutorial shows you what plants look like when defoliation is going to be helpful, and when it’s better to leave your plant alone.
  • Lower humidity – Since each leaf is continually adding water vapor to the air, defoliation decreases the overall humidity of a grow space. That could be a good or bad thing depending on your local environment, but it’s common for growers to struggle with high humidity in the grow space once plants start getting big with tons of leaves.
  • Better airflow within the plant – Lack of airflow is associated with problems like mold and pests. Air doesn’t travel easily through a bushy plant.
  • Denser buds – If you follow the instructions as written, defoliation reduces the number of small, airy buds that often get thrown into the trim pile after harvest. No one wants tons of tiny, wispy nugs! In my experience, defoliation helps ensure all buds at harvest are weighty and dense.
  • Longer primary buds – Proper defoliation allows light to penetrate further down into the plant, and buds are typically longer as a result. With very bushy plants, buds are often only an inch or two tall. We want foot-long colas!

What defoliation has not been proven to do:

  • Increase yields – I believe that defoliation increases yields when done correctly. However, this is based on my feelings from years of experimenting with different levels of defoliation. I’ve never done a side-by-side experiment, and have never seen a defoliation test documented by anyone else. That means there is no objective proof that defoliation increases yields. That being said, if you follow the instructions below to a T, you will get great results, and you will achieve the factors listed above. I’ll show you picture-proof of what happens when I defoliate so you can decide for yourself.

These plants are so bushy that the entire bottom half is in shadow. Light and air are not penetrating into the plants at all.

Example of tending to a cannabis canopy - these plants are too leafy and need to be defoliated!

How does defoliation work? There is a lot of debate on the actual mechanism that’s causing the changes people see from defoliating their plants. This defoliation article goes into the theories, but today I’m focused purely on the practical application and showing picture-proof so you can decide for yourself if it seems like something you want to do in your garden.

What’s the Big Deal with Bushy Plants?

Plants with too many leaves for their size often raise the humidity of the grow space above appropriate levels. High humidity often triggers problems such as:

  • mold or mildew
  • bud rot
  • pests
  • poor bud development

No one wants any of that!

Buds that are hiding in the shadows also stay small and airy. The following plant was manifolded (notice the base), which usually helps prevent airy buds, but the plant was never defoliated in the flowering stage. Although the top few inches of buds thickened up beautifully, every bud that grew below the thick canopy stayed small.

Check out the buds that didn’t get light or air in the flowering stage.

All the hidden buds became tiny wisps of white hairs with no substance (this is a closeup of the same picture).

Proper flowering stage defoliation reduces the number of tiny buds getting thrown into the trim pile, so all the buds you do harvest are more likely to be thick and chunky.

Learn more about the problems associated with too-bushy plants

 

How to Defoliate Plants in the Flowering Stage (with No Chance of Stunting)

Warning: Defoliation can hurt yields when done incorrectly. It’s essential to follow these steps exactly (especially when NOT to defoliate), to ensure you never experience stunting or reduced yields.

Ready to start defoliating?

Defoliation involves removing fan leaves in a specific way. It can be used in the early flowering stage to help increase yields

1.) Identify IF your flowering plant is too leafy

Plants often “bush out” after they start flowering. Not all strains, and not in all setups, but it’s common. Especially if you’re growing happy, vibrant plants. A lot of new defoliators get confused with when to defoliate and defoliation schedules. When is defoliation is a good idea? When will defoliation make things worse?

Defoliate when…

  • The plant is so bushy that light and air can’t get through
  • Leaves are laying on top of each other forming wet spots
  • Leaves are covering bud sites and can’t be tucked away
  • Plants are still in the first 6 weeks of the flowering stage

But what does “too bushy” look like?

These plants would benefit from a good plucking!

An example of a good candidate for defoliation - this cannabis plant in the vegetative stage is so bushy that light isn't making it down into the plant to fatten up the buds under the main canopy

These plants are too bushy and should be defoliated

Defoliation: beforeBushy plants raise the humidity. Too-high humidity can result in mold, bud rot, pests, and mildew.

Too-bushy marijuana plant is only making short, tiny buds

These plants are only a few weeks into the flowering stage. Light and air are not getting into the plant. Defoliate!

Do NOT Defoliate…

  • The plant is not leafy – defoliating a sparse plant can stunt growth
  • It’s past the first 6 weeks of the flowering stage – defoliation is much less effective once bud structure is set, and the plant isn’t growing new leaves.

The most common beginner mistake is to defoliate a plant that’s not bushy or to over-defoliate. This can stunt plant growth and reduce yields. So the most critical aspect of defoliation is being able to determine when the plant has too many leaves and when it needs to be left alone.

These plants are not too bushy. Leave these plants alone!

Ok, now you should have identified whether your plants are too bushy. Do not defoliate if you’re not sure. Wait and see. If you feel confident that you’ve got too-bushy plants, onto the next step!

 

2.) Remove big fan leaves if the plant is too leafy

Whenever defoliating, focus on removing big fan leaves with long stems. These leaves cause the most shade and stick out from buds, causing a thick canopy that can’t be penetrated by light or air. Focusing only on the biggest leaves reduces the chance you’ll stress out your plant. It’s also smart to remove leaves that are blocking bud sites (and can’t be tucked) or leaves that are laying on each other creating wet spots.

Which leaves to defoliate?

  • Big fan leaves on long stems
  • Fan leaves that are blocking bud sites (especially leaves at the top of the plant that can’t be tucked away)
  • Fan leaves laying on each other creating wet spots

Remove leaves big fan leaves with long stems

Focus on leaves that are blocking bud sites from receiving direct light or airflow. Especially if the leaf is directly between the bud site and your grow light.

Examples of fan leaves that are good candidates for removal

Be careful not to accidentally remove bud sites when defoliating a cannabis plant in the flowering stage

There should still be plenty of leaves left after defoliation. Taking too many leaves so that your plant is bare will often stunt the plant’s growth. When in doubt, take less than you think. You can always take more leaves later, but you can’t put them back.

Before defoliation

After defoliation (this is on the lighter side)

After defoliation, there should still be leaves all the way down each branch. Only the biggest fan leaves should be removed.

This example is on the extreme side of defoliation. Some growers take even more leaves, but I would never suggest a beginner defoliate more than this.

 

3.) Leave plant alone (unless it gets too bushy again, then back to Step 1)

Once a plant has been defoliated, it should receive TLC (tender loving care) and otherwise should be left alone so it can do its thing. Only defoliate again if it starts looking bushy like the examples in Step 1.

Just remember that you don’t want to be taking leaves after the plant has stopped growing new ones. Try to finish all defoliation before the plant has been flowering for 6 weeks unless you have to (for example, you see wet spots on the leaves).

Let plants do their thing until harvest!

The next plants weren’t defoliated as heavily because they are autoflowering plants, which tend to be more sensitive to stunting. But notice they’ve been defoliated enough that the buds are exposed from top to bottom. That’s what’s most important.

Buds are visible from top to bottom as buds form

Here are those plants a few weeks later. I didn’t do anything after the above picture. I just let them grow and maintained a great environment.

Cannabis plants growing under a 315 CMH grow light (not long before harvest)

Now you have all the info you need to become a great defoliator! You don’t need to use any particular schedules. As long as you follow the 3-step process outlined above, you won’t stunt your plants, while still getting the benefits of defoliation.

I want a more specific defoliation schedule (we’ve got you covered!)

 


 

More Info: Why are Leafy Plants Such a Problem?

Beyond the debate about bud quality and yields, there are other reasons to defoliate. When most of a plant is in the dark as a result of too many leaves, air usually can’t get through the plant either.

No matter the stage of life, your plant can get white powdery mildew (mold that looks like flour) from wet spots and high humidity

White Powdery Mold can also attack stems and buds, not just leavesNo one wants mold on their plants!

In the flowering stage, defoliation may be necessary to prevent harm to your buds.

Wet spots are dangerous to buds because they increase the chance of bud rot

Usually Botrytis fungus infects just parts of buds, in patches.

In the following picture, the left plant is too bushy. You can tell that air doesn’t seem to have a path through the plant because most of the plant is in darkness even though the light is a strong 600W HPS, which normally pierces deep into the plant. There are tons of leaves lying on each other on the left plant. As you get closer, you’ll see that there are wet spots between the leaves that are touching. Wet spots are dangerous to buds.

This left plant is too bushy, putting it at risk of wet spots and bud rot. The right plant allows air to travel through the plant.

"Schwazze" your cannabis plants with defoliation. These plants are 3 weeks into the flowering stage. The right plant has just been defoliated a second time, while the left plant needs to be defoliated to finish up the schwazzing techniqueThe plants above were two different strains, so I wouldn’t count this as a side-by-side, but the defoliated plant produced several ounces more than the bushy plant (and the bushy plant lost a cola to bud rot).

The first sign of bud rot is usually sick leaves appearing on affected buds.

One single cola with yellow leaves - a sign of bud rot!Look closer, and you see the bud looks discolored at the base of the unhealthy leaves

A cannabis bud with bud rot. It still looks mostly okay on the outside (except the leaves) but there's a nasty surprise inside

The bud usually splits open easily open to reveal the mold and rot inside

Opening up the marijuana bud lets you see the mold growing inside.

Be extra aware of high humidity, wet spots, and leafy plants when buds are getting fat and dense. Learn more.

 


 

 

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