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Fimming Cannabis Plants: Complete Tutorial

Fimming Cannabis

Fimming cannabis is an essential, high-stress training technique every marijuana cultivator should learn to encourage bushy, yet compact, flowering.

The term FIM stands for “F*ck I Missed” and is almost like topping, as it involves removing the apical portion of the stem. This method maximizes your cannabis harvest while offering benefits such as promoting lower growth.

Fimming is a simple procedure any grower can master. It has developed over the years from the mistakes learned while cultivating marijuana.

Are you ready to learn everything there is to know about fimming your weed crops? Let’s dive into the techniques, its benefits, and how to FIM correctly.

What is fimming cannabis and how does it work?

Fimming Cannabis

Fimming involves cutting off a portion of your plant’s tip. The name hints at how the technique may look sloppy, as if the grower messed up a pruning attempt. It’s an effective and simple method that increases the number of main colas, similar to topping.

The primary difference between the two procedures is that you purposefully leave 25–30% of the top shoot remaining when fimming cannabis. By cutting through the vegetative material at the tip, you create a few new main colas. 

Instead of two heads shooting from the snipped stem, four appear, creating a bigger yield. 

Pruning the plant in this manner disrupts its auxin delivery system by interfering with its primary growth hormone.

Fimming allows the plant to focus its energy on the lower foliage and regrow with lateral dominance after 5–7 days. Its lower branches and shoots experience faster development.

The crop’s growth structure and appearance change during the vegetative period, creating thicker, bushier cannabis plants.

Topping requires cutting the entire tip off the cannabis plant’s main stem, resulting in a shorter crop. The technique transfers the main shoot to the two lower ones, forcing the plant to create two apical buds. 

How to FIM correctly

Follow this quick and easy tutorial on how to FIM your cannabis plant:

  1. Find a sharp pair of scissors and wipe them clean with alcohol to kill any bacteria.
  1. Gently grip the two leaves on the highest point of your cannabis plant with your thumb and finger.
  1. Use your scissors to do one clean horizontal cut, removing approximately 75–80% of the shoot tip. If your tools are sharp, this step should be easy.
  1. Don’t touch the remaining foliage on the tip. You should notice fresh growth after a week.
  1. Repeat these steps if necessary until you’re happy with the appearance of your cannabis plant. Be aware that over-trimming may encourage heavy flowering.
topping vs fimming

Mistakes to avoid when fimming cannabis

Keep these essential points in mind before you FIM your crops:

  • Avoid using blunt scissors. You want to achieve a clean, sideways cut or you risk damaging the foliage left behind.
  • Don’t try fimming on autoflower cannabis plants, as it causes them to become stunted and produce very few flowers.
  • If your plant is producing buds, fimming causes serious stress and hinders flower growth.
  • Only use this technique if your plant has time to recover. It’s best during an 18/6 light cycle.
  • Cut with care. An incorrect snip leaves weak branches which won’t hold the buds’ weight.
  • Fimming cannabis incorrectly could create a callus where nothing grows, so practice your pruning.

If you have several plants, don’t FIM them all. Leave some uncut crops in case anything goes wrong with your technique.

When to FIM cannabis

FIM your plants during the early vegetative stage, when they’re at least 3–4 weeks old with 3–5 nodes.

During this period, they prioritize developing fresh shoots and can handle the stress of pruning. Fimming too early damages the plant and slows seedling growth.

Cutting during the flowering stage often shocks the crop beyond recovery, resulting in it using energy to heal instead of grow. It also won’t produce any new shoots.

How do cannabis plants react to fimming?

Fimming encourages plants to develop denser canopies, as cutting the tip results in 2–4 new lateral branches growing.

In normal crop development, the plant focuses on upward growth, as its tip contains hormones called auxins. These proteins direct energy to the top, ensuring the stem grows taller and catches more sunlight than others around it.

After fimming, the plant scrambles to redirect auxins, causing it to grow wider instead.

Encouraging multiple fat colas to form might make your marijuana top-heavy. Should your branches appear weak, tie them to a trellis to ensure proper lateral growth.

Benefits of fimming cannabis plants

These are some advantages to look forward to when fimming your cannabis plants:

  • Produces multiple branches, which increase your harvest.
  • Causes little stress on the plant and helps it grow sturdier, as it has to boost its growth phase.
  • Use it in combination with other pruning techniques, such as super-cropping or low-stress training.
  • Promotes lower growth and keeps crops short, which is useful for growers with limited height in their cultivation areas.
  • Encourages a uniform canopy for using a ScrOG.
  • Eliminates popcorn buds from forming during the flowering period. 
  • More effective than topping, as it creates four main shoots instead of two.
  • It’s possible to fim cannabis plants multiple times to increase bud density.
  • Precision isn’t the goal. Even a poor topping attempt can produce a multi-cola FIM.

Other techniques that maximize harvests

Fimming Cannabis

It sometimes isn’t enough to simply FIM your plant’s tip to increase your yield. Other techniques can also further your crops’ bloom development. Combine them with fimming to enjoy a scale-tipping harvest.


Lollipopping involves removing any fluffy lower bud sites from the plant, helping it to develop bigger blooms. The technique aims to focus the crop’s energy on growing large, dense nugs rather than popcorn.

Cultivators typically pinch away lower growth during the third week of flowering.

Screen of Green 

Improve any high-yield cultivation technique by using a Screen of Green (ScrOG). The method optimizes your lights by bringing up the buds to the top of the canopy

Lay out a mesh screen across your cultivation space, then bend and fold shoots to fill as many squares as possible. Begin this process in the vegetative period and continue until early blooming.

Some growers also like to make the screen adjustable so they can raise its level if growth becomes abundant. 

Plants grown using ScrOG don’t waste energy on growing small side shoots or fluffy flowers. This development pattern increases your yield per square meter.

Low-stress training

Using low-stress training (LST) while fimming cannabis plants maximizes the light reaching your crops and increases your yield. The method doesn’t involve cutting or splitting the stems, preventing any mistakes that could kill your marijuana.

Gently bend and tie the tall branches to put them on the same level as the shorter ones. The technique changes the plant’s overall shape to improve light efficiency and increase bud sites.

Get fimming now

Fimming is an effective pruning technique that increases your cannabis yield by promoting lower branch growth.

It’s used during the vegetative stage and requires cutting 75% of the tip, leaving it to regrow multiple branches. Fimming isn’t as final as topping, allowing you to repeat the method until you’re happy with the shape or the bush density.

It also works with other training practices, such as LST or ScrOG, which further increases your harvest.

Get your own cannabis seeds at Homegrown Cannabis Co. today and try fimming for yourself. With practice and a little patience, you could improve your yields and the efficiency of your cultivation area.

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