Topping Vs FIMing Cannabis - Instruction Guide | Grow Weed Easy

by Nebula Haze

Table of Contents

Intro: Cutting Cannabis for Better Structure

Topping vs FIMing Cannabis

Tips for Topping & FIMing Weed Plants

• Don’t Cut Too Early!
• Don’t Cut Too Late!
• How to Know It Worked 

How to Top Cannabis Plants (Topping Tutorial)

How to FIM Cannabis Plants (FIMing Tutorial)

Cutting Cannabis for Better Structure: Topping & FIMing

Topping and FIMing are two cannabis plant training techniques that involve “pinching” or cutting off some of the top growth. These techniques give you a free way to achieve better plant shape (to make better use of the available light), create more top buds, and overall achieve bigger yields.

Topping: Cut off top of plant through the main stem (between nodes).

FIMing: Remove newest growth, but don’t cut through main stem.

Topping and FIMing, like all cannabis plant training techniques, are designed to help growers get a more desirable plant shape and bigger yields. The cool thing about plant training is it increases cannabis yields without having to change any other aspects of their grow.

Notice how these cannabis plants have many buds instead of just one. Topping and FIMing help you grow plants like this.

Cannabis plants don’t naturally grow in a way that takes full advantage of indoor grow lights. Since only tops buds get full light levels, a lot of light gets wasted indoors when cannabis plants are allowed to grow naturally without “training”.

Check out the above example. The cannabis plant on the left was allowed to grow naturally, which resulted in the classic cannabis “Christmas tree” shape. This natural shape is not efficient under indoor grow lights because it only produces one main bud (also known as a “cola”).

The plant on the right was topped or FIMed as a seedling. This broke the apical dominance of the main cola, and the plant grew many colas and therefore multiple big buds.

Quick Reference of Cannabis Training Terms

What does “topping” stand for? “Topping” is when you cut off the top of the plant. It’s common to hear growers phrases like “top the plant”, or a grower “topped” the plant.

What does “FIM” stand for? FIM is like topping, but you take off a little less. The acronym “FIM” stands for “F*ck I Missed.” FIMing originally referred to growers accidentally pinching off some top growth instead of fully cutting off the top. FIMing has become known as its own technique as it has slightly different results compared to topping (recovery time, number of colas produced in one cut, etc.).

What is a “cola” and why do they matter? “Cola” is Spanish for “tail” and refers to any big, long, thick bud. When dried, these buds may look like a tail, hence the nickname. As a cannabis grower, you want a lot of colas on your plant to maximize yields. Colas grow at the top of stems, so when a plant is young, growers try to get their plant to grow many main stems. This rewards you later. Even before the plant starts making buds, the main stems are still often called colas or sometimes “mains”.

Buds the size of 2-liter cola bottles. Really puts the “cola” in cola!

Some cannabis strains naturally grow bushy with many buds/colas, but most strains only naturally grow one and therefore produce lower yields indoors without your help.

With both topping and FIMing, the growth tips that become new colas are already present. They just get bigger and become colas because topping and FIMing breaks the symmetry of the plant and exposes these growth tips to light and air. Instead of focusing on just one cola, the plant starts focusing on many growth tips until they become colas of their own.

Main Idea: Topping & FIMing remove or damage top growth, signaling the plant to put energy into lower growth tips.

By damaging the main stem, topping and FIMing encourage the plant to spend energy growing many colas instead of focusing on just one.

Lower stems will become new colas once they’re exposed to light and air, but they develop much faster when the main cola’s dominance is broken by topping or FIMing.

Notice how these growth tips have started developing and rising up after plant is topped or FIMed. On this plant, the fan leaves were removed so you can see the new colas and overall structure more easily.

Topping vs FIMing

When it comes to FIMing vs Topping plants, it’s more a matter of growing preference than anything else. They both work great for growing marijuana!

Topping Cannabis

• Cuts off top of plant through main stem (sever the stem in between sets of leaves)
• Creates 2 main colas at the top of the plant, and gentle bending of the tallest stems can be used to expose lower stems and create more colas.
  • Note: Bending over stems to make the plant more bushy is often referred to as LST (low stress training).
• The 2 new top colas are evenly spaced (attached to the stem in the same place).
• Unlike FIMing, topping can also be used to reduce the height of plant in vegetative stage.
• More stressful to the plant than FIMing. Vegetative plants may need a few days to a week to recover from topping.

This videos shows you how to top a cannabis plant.

The extra main stems grow from above the node where you make the top cut. This next video shows the whole cannabis topping process, in a timelapse format, showing what topping looks like in 10 days. The lower growth tips also begin rising up, and can produce even more main colas.

Here’s a video showing what a plant looks like in the 10 days after being topped. Thanks to grower fuzzygrow for this awesome cannabis topping timelapse!

Read the complete guide to topping cannabis plants!

FIMing Cannabis

• Removes top growth, but does not cut through stem
• Creates 2-4 main colas at top of plant, and LST can be used to create more.
• New colas created are not evenly spaced
• Does not reduce height of plant
• Does not stress plant compared to topping, so plants recover more quickly or don’t even notice

FIMing takes off less than topping.

Before FIMing (dots are where the new colas will be)

After FIMing (leave about 20% growth)

Read the complete guide to FIMing cannabis plants!

These plants were FIMed early in the vegetative stage. The stems were gently spread out, resulting in this productive shape.

In either case, whether you top or FIM, you will end up with a wider, bushier plant that doesn’t grow just one main cola in a Christmas tree shape.

With Topping & FIMing, you easily achieve cannabis plants like this…

…In basically the same amount of vertical space as a plant like this. Why not have many buds instead of just one?

Some growers will use several phases of topping or FIMing to produce cannabis plants with dozens of colas. Some techniques take this to the extreme, for example, manifolding (also sometimes called “main-lining”) is a technique that uses topping several times to make a cannabis “manifold.”

Tips for Topping & FIMing

Here are some extra tips to ensure topping and FIMing your marijuana plants goes perfectly every time!

Don’t Top or FIM Too Early!

With both topping and FIMing, you remove some of the growth on the end of a cola of a young marijuana plant, which causes the plant to stop focusing on one cola (like a Christmas tree) and instead to create many bud-laden colas (grow bushier).

If you Top or FIM the plant too early, it will have a hard time recovering. It may seem like a good idea, but you will get the best results and fastest recovery if you wait until the plant has enough nodes.

Wait Until Plant Has at Least 3-5 Nodes (FIMing) or 4-6 Nodes (Topping)- Topping or Fimming a Too-Young Seedling Will Dramatically Slow Down Growth. If You Wait Until Plant is Growing New Leaves Every Day, Recovery Will Be Much Faster.

Growers use the plant’s natural response to FIMing/topping to produce short bushy plants with many colas. After the plant has been switched to the flowering stage, the wide spread of colas allows the plant to efficiently use indoor grow lights to produce the biggest yields possible.

If you choose to use either of these methods, you will get the best results by doing it when the plant is young, usually when it has around 3-6 total nodes formed. Generally, you would only want to FIM a plant that has just 3 nodes, and wait until 4 nodes to top the plant.

These young cannabis plants are almost ready to be topped or FIMed. Cannabis plants can be FIMed before they can be topped.

You get great results by breaking the tendency of the plant to grow one main cola while the plant is still short, because you can arrange your multiple colas however you want as the plant develops, instead of dealing with a Christmas tree-shaped plant.

You can also top or FIM your plant later in the vegetative stage, but you will have a longer main stalk, giving you less ability to arrange the colas the way you want.

After being topped or FIMed, your plant will need some time spent recovering in the vegetative stage, though generally this just causes the plant to ‘fill out’ more instead of growing taller, which is often desirable for indoor growers.

This plant was trained for ~2 dozen colas in the vegetative stage

Important: Don’t Top or FIM in the Flowering Stage; It’s Too Late!

Topping and FIMing techniques should only be used in the vegetative stage! In fact, any training technique that involves cutting or damaging your plant should optimally be done in the vegetative stage of cannabis growth, before the flowering/budding stage begins.

In the flowering stage, only gentle training techniques such as LST or other types of bending should ever be used to change the shape of the plant.

A plant with many colas can only be achieved by training a plant from early in the vegetative stage

Cannabis plants are much less tough in the flowering stage, and they no longer are growing vegetatively (producing new stems or colas) by the time they hit about week 6.

If you watch a plant in the flowering stage, you’ll see that it doesn’t get taller or develop growth nodes after about week 6. It only “focuses” on making buds. Topping or FIMing at this point won’t do any good. Damaging your plant during the budding stage will often cause a reduction in your final yields because you’re just taking away more plant/bud sites and may cause unnecessary stress during the crucial bud-building phase.

By the time your plants are in the flowering stage, much of the growth structure has already been created, and you generally need to try to manage as best you can if your plant has grown into a shape you don’t like.

What if my plant is already too tall in the flowering stage?

If your plant is already too tall in the flowering stage for your grow setup, you’ve got to take immediate action to prevent the plant from getting any taller.

My suggestion is to use bending (LST) your plant to control the height of further growth. Very careful supercropping can also be used if you have a stem that is far taller than the others.

Once flowering is fully underway (after the initial flowering stretch), the plant will not grow much taller, so you can just try to hang on until harvest. Sometimes you may even have to harvest a particularly tall cola ahead of time to prevent it from getting bleached or burned. Don’t stress, it happens to us all! I recommend trying to take it as a learning experience 🙂

How Can You Tell That Your Plant is Diverting Energy to New Colas?

Almost immediately after topping or FIMing you cannabis plant, the connections to each node become enlarged at the base. These thickened connections demonstrate that your cannabis plant is spreading energy more evenly across the whole plant.

When you see your plant thicken connections like this, it means that the plant is strengthening the “internal system” of the stem, so it’s easier to deliver nutrients and other building blocks. This results in faster growth, bigger colas, and increased yields for each of the affected stems.

The thickening that happens at the base of stems is one sign that the plant is diverting energy to the new colas (where before it was putting the majority of its energy into just the one main cola).

As time goes on, the most used stems can become so thick they’re almost like tree branches.

Topping Your Cannabis Plant

When topping your cannabis, you cut off a growing node of the plant, reducing the height instantly. This can be especially beneficial if you’ve let your plant get too tall. Topping also increases the number of colas, which can give you more bud at harvest,

Never Top Cannabis in the Flowering Stage!

When topping your marijuana plant, it’s best to top the plant when it is young, and has 4-6 nodes (sets of leaves) in total. Although you could do it a little earlier, you’re more likely to accidentally stunt your plant the younger it is. Additionally, the less actual plant matter you take off, the less likely the plant will get stressed. Think about it, if you’re taking off 10% of the plant it will have much less effect than if you took off 30% of the plant.

“Topping” the plant means cutting off the newest node on your marijuana plant’s main cola in order to split it into two. However, the word “topping” can also refer to cutting of the tip of any stem.

A good place to top is directly above the leaves of the next node. In other words, cut through the stem right above its next set of leaves from the top.

Topping will cause your plant to transfer its energy to two new main colas, as indicated by the two yellow dots in the diagram above.

Make sure to leave a little extra stem behind for reinforcement. This helps strengthen the two new colas to prevent them from splitting down the middle.

Timelapse Video of a Cannabis Plant’s Recover After Being Topped

These 2 new colas for a V which can easily be bent to spread wide. You can top these two new colas a few weeks later and have 4 total colas. This can even be doubled to produce 8 colas that all come from a single “manifold.” Learn more about manifolding cannabis.

Another benefit of topping is how the plant tends to grow bushier afterwards, spreading its energy much more evenly around to the whole plant.

Often lower branches rise up to become new main colas. This is especially true if you combine Topping with LST to open up the plant so the lower branches get more light.

If you’ve grown a very tall plant, it’s also possible to top your (vegetative) plant down to the node you want to reduce the height, but remember that all the time the plant spent getting tall will be lost. In order to get the most flexible colas, without losing vegetative time, try to top or FIM early in the plant’s life

If you’re still in the vegetative (non-budding) stage and plants are growing way too tall, you can top the plant immediately to remove height as needed. The time spent growing the extra growth will be lost, so this may add time to the veg stage.

Note: Don’t use topping to reduce the height of auto-flowering cannabis strains! They don’t have time to recover. Learn about how to top auto-flowering strains to increase yields.

If you want to top the plant multiple times, you may be interested in learning about main-lining (creating a manifold – a plant training technique).

Read the complete guide to topping cannabis plants!

FIMing Your Cannabis Plant

FIMing is generally less traumatic to the plant than topping. FIMing barely slows down growth and can stimulate the plant to grow up to 4 main nodes in one cut (instead of just 2 like with topping).

FIMing will often not make symmetrical colas like topping. The resulting number of colas becomes less predictable.

With FIMing, the 4 new colas created are not evenly spaced, and do not join to the stem in the exact same place. This might not matter to some growers, but is useful to know when using a technique like main-lining where it’s important for nodes to join at the same place on the stem.

Never FIM Cannabis in the Flowering Stage!

More About FIMing (Pinching) Your Marijuana Plant

Note: FIM (unfortunately) stands for “F*ck I Missed” referring to the fact that it’s like topping your plant, only you’re taking off about 20% less.

With Fimming, you can get less consistent results than with topping. If you don’t actually pinch off the top growth just right, you may end up with only 2 or 3 colas instead of 4.

The 4 colas also may not grow as evenly as the 2 tops that are achieved with topping. If you top your plant twice, you will end up with 4 colas just like FIMing, but you will generally get more consistent results. However, topping the plant slows down growth more than FIMing, so it’s up to you to decide what’s best for your situation.

All you need to do is remove the top growth

Instead of cutting the plant, which can sometimes accidentally result in topping, some growers may choose to crush the top of the plant between the fingers, without removing any part of the leaves. However, I recommend removing plant matter and only leaving about 20% behind. This gives more consistent results. Sometimes if you just try to crush the top the plant doesn’t even notice!

It’s best to FIM a plant when it has 3-5 nodes. While you can FIM a taller plant, there will still be a long main stem and your new colas won’t be as flexible as colas from an early FIMed cannabis plant.

FIMing an older plant will leave you with one long main stem, but lower growth tips start growing up

FIMing is sometimes referred to as “pinching off” the top of the plant. To FIM the plant, you simply pinch or cut off the newest growth, taking just the tips of the newest growth off, and making sure to leave a bit behind.

FIMing causes the plant to grow very bushy, and the other nodes will becomes strengthened just like when topping.

FIMing barely slows down growth since very little of the plant is removed.

Be warned, when FIMing your plant, the top growth on the plant will look weird when growing in. This is normal!

Read the complete guide to FIMing cannabis plants!

Topping and FIMing are both great choices for cannabis growers.

• FIMing – If you’re worried about stunting your plant, then use the FIM technique.
• Topping – If you want the most consistent results, then use the topping technique.

The best technique depends on what you’re trying to achieve!

Jump to…

More Plant Training Techniques!

LST (low-stress training)

Super cropping

How long does it take to grow cannabis?