Fimming, also referred to as FIM, is a popular high-stress training (HST) method that growers use to maximize yield from cannabis plants.

What is Fimming?

Fimming is a technique similar to topping, although the main difference is exactly where you cut the stem and how much of the plant you remove. The term FIM is actually an acronym for F#!ck, I Missed”, as it can appear to be a poor attempt at topping. When fimming is done correctly, it can considerably increase your crop’s harvest.

Fimming encourages your plant to produce new branches that grow out sideways to make your plant bushier and more spread out instead of growing into one tall Christmas tree shape. Fimming encourages the growth and development of more lateral branches and shoots further down the plant, which makes for a denser plant canopy with increased yields.

How is Fimming Different from Topping?

Topping a cannabis plant means cutting off the entire top of the main stem above the fourth node, which causes two apex stems to grow out from that same area instead of one. When fimming, growers cut the top of the main cola as well, but only remove about 75% of it, and leave what looks like a tuft of a stem. This should encourage four new growth tips instead of the typical two when topping.

When to FIM

You should only FIM during the vegetative, or growth, stage after your plant is past the seedling stage. If you FIM after your plant starts to produce bud, you risk stressing the plant, which could throw it into a hermaphrodite or could encourage disease. Timing is important when fimming, and you want to make sure that your cannabis plant has sprouted a minimum of three nodes with branches and leaves.

How to FIM

When the time is right, use clean, sterile shears and cut the top section through the main growth tip. Ideally, this then grows into four new shoots that produce new colas for significantly more buds.

1. Choose the very top growth tip of the cannabis plant
2. Pull the small leaves back gently around the tip and hold the green tip with your thumb and index finger
3. Make one clean cut to remove about 75% of the tip
4. Repeat this FIM process on other growth tips you’d like to branch out

Some growers use shears or a razor with a curve, which is thought to direct the new growths sideways in the desired direction, although the jury is out as to whether or not this actually improves results over making straight cuts.

The Many Benefits of Fimming

Fimming is advantageous for many grows, producing a fuller, denser canopy. Some of the most recognized benefits of fimming include:

Bushier, denser plants – removing the top growth tip on cannabis plants encourages lateral branches for a more compact, dense growth structure. This can be a big advantage if you want to keep your plants under the radar, without peeking over the neighbor’s fence or hitting the top of your grow tent.

Bigger yields – HST methods like fimming and topping encourage multiple colas instead of just one main cola to significantly maximize overall yield.

Improved light penetration and absorption – light reaches more leaves with more lateral growth, which improves overall growth.

Improved quality – with greater light absorption, plants are optimized to direct more energy to producing buds, which results in improved potency and quality of cannabis flower.

The main reason growers perform fimming or topping is to maximize yield, i.e. lots of buds, although better light absorption and improved quality are other big benefits. Remember, quality plants start with quality seeds, and you can find the best quality weed seeds at The Seed Cellar.

The Seed Cellar is one of the largest online seed banks and one of the very few with a brick-and-mortar storefront. Our knowledgeable and helpful staff are available to take your call and help you choose the best Cannabis seeds for your grow. Call us with any questions and check out the seed bank today for quality seeds sold in original breeder packaging.