Topping and FIMming Cannabis Plants

The cultivation of cannabis has greatly advanced over the years, owing to ongoing research and development, as well as increased legalization globally. Two major techniques that have gained substantial attention from cannabis growers are Topping and FIMming. These horticultural techniques are practiced with an aim to boost yield, manage plant growth, and maximize light exposure. This article explores these two methods, their differences, benefits, and how to apply them in cannabis cultivation.

Introduction to Topping and FIMming

Topping and FIMming are high-stress training (HST) techniques used in the cultivation of cannabis. They involve the physical manipulation of plants to alter their growth pattern, typically resulting in a bushier plant with more colas. These methods force the plant to distribute its resources evenly among several growth sites rather than focusing them on a single main stem or “cola.” This results in potentially larger yields and more efficient use of light.


Topping is a technique where the grower cuts off the top of the cannabis plant at the end of the vegetative phase or in the early flowering phase. This encourages the plant to grow two main colas instead of one, effectively increasing the potential yield. The primary reason behind topping is to break the apical dominance or the plant’s natural tendency to focus energy on the main stem’s growth.

This technique triggers the plant to divert growth hormones to the lower, dormant buds. The hormones, known as auxins, stimulate the growth of two new main colas and several side branches. This results in a bushier plant and more flowering sites, ultimately leading to a larger yield.


FIMming, an acronym for “F*** I Missed,” is another technique used to increase a cannabis plant’s yield. This technique is similar to topping, but instead of completely removing the top of the plant, the grower only removes approximately 75-85% of the tip. This technique, sometimes seen as a less stressful variant of topping, can lead to the creation of four new colas instead of the usual two from topping. Like topping, FIMming also breaks the apical dominance, resulting in more branches and a bushier plant.

The Process: How to Top and FIM Cannabis Plants

Both topping and FIMming should be done during the vegetative stage, as the plant requires time to recover and continue its growth unhindered.

Topping Cannabis

To top a cannabis plant, start by identifying the newest growth on the main stem, typically located at the top of the plant. Using a clean, sharp pair of scissors or a razor blade, make a clean cut just below the newest node. Ensure that you leave a small amount of the stem above the node to avoid damaging the plant. This cut forces the plant to split its energy between the two new main colas.

FIMming Cannabis

FIMming, on the other hand, requires a bit more precision. Instead of completely removing the newest growth, the grower should cut approximately 75-85% of the new growth at the top. It’s crucial to leave some of the new growth behind, as this encourages the plant to split growth among four new colas.

While FIMming requires more accuracy, it can potentially produce twice the number of new growth sites compared to topping. However, the success of FIMming can be less consistent than topping, given the precision required.

Advantages and Disadvantages

Both topping and FIMming provide significant benefits to cannabis cultivation, such as increased yield and better light distribution. They also help control the plant’s height, which can be especially beneficial for indoor growers with limited space.

However, they are high-stress techniques and can potentially harm the plant if done incorrectly or too frequently. Topped or FIMmed plants may also require more time to recover and reach full growth, slightly prolonging the vegetative phase.

It’s essential for growers to consider their specific cultivation conditions and the characteristics of the cannabis strain they’re growing. Some strains may respond better to these techniques than others.


Topping and FIMming are potent techniques to increase cannabis yield and manage growth. These methods, while requiring a certain level of skill and care, can significantly enhance the productivity of both small-scale and commercial cannabis cultivation. However, growers should always consider the particular needs of their plants and strains, as well as their cultivation conditions, to choose the most suitable technique. With practice, topping and FIMming can become invaluable tools in the cannabis grower’s toolbox.