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The Difference Between Topping and Fimming

Topping and fimming are two standard high-stress training techniques that cannabis growers rely on to boost their yield. Both alter the shape of a plant so that it becomes bushier and produces multiple colas. This allows growers to make more efficient use of space and generate a better harvest, so it’s worthwhile learning a little about these two simple hacks.

Topping And Fimming – What Are They?

Topping and fimming both involve removing the very top growth of a cannabis plant. Doing so disrupts the plant’s regular growth pattern, causing it to develop more side branches and expand outwards rather than upwards.

The one difference between the two methods is that topping involves removing the plant’s entire tip. In contrast, fimming only removes about 75 percent of the tip, leaving some foliage still attached. In both scenarios, the pruning of the top growth causes the plant to redistribute its growth hormones. Instead of channelling all its energy into producing one main cola, it now divides its resources among all of its shoots.

Without topping or fimming, cannabis plants usually grow in a Christmas tree shape, with one dominant cola in the middle and several smaller side branches. This means they take up a lot of vertical space and only produce one decent clump of bud come harvest time. Most growers, however, would much prefer shorter plants with multiple colas – and that’s exactly what you get with topping and fimming.

Topping And Fimming – Which Is Better?

Topping and fimming each have advantages and disadvantages, so choosing between them will depend on your specific needs.

When a plant is topped, the two side nodes immediately beneath the removed tip take over and develop into colas. With each topping, therefore, the number of colas doubles. What’s more, these two new branches always grow in a symmetrical pattern, which means plants rarely become unruly or form into awkward shapes.

The downside to topping involves cutting the main stem, which can be rather stressful for a plant. This means that plants may take some time to recover, and growth can be slowed or delayed for a while.

Fimming, on the other hand, is much easier for a plant to deal with as it doesn’t entail the cutting of the stem. The term itself comes from the acronym FIM, which stands for ‘fuck, I missed.’ As the name suggests, fimming looks a bit like topping gone wrong, as the cut is made towards the base of the tip rather than below it. However, there’s nothing accidental about fimming, as the technique often sparks the growth of three or four new colas.

Recovery tends to be much quicker after fimming, as the method doesn’t stress the plant as much as topping does. The expanded number of colas also makes this technique particularly appropriate for growers with a small number of plants or with severely restricted vertical space. However, the new growth promoted by fimming is less uniform than that generated by topping, so plants can become unruly. It’s often necessary to provide extra structural support to fimmed plants to keep them upright.

Tips For Topping And Fimming

As previously mentioned, both topping and fimming cause plants to become stressed, slowing their growth. Minimising this stress is, therefore, a major priority for growers.

The most effective way to achieve this is to ensure you only top or fim your plants at the appropriate time. It’s essential that plants have developed their roots and stems enough to withstand a shock, so attempting to apply stressful techniques to very young plants is an absolute no-no.

Generally, growers should not top their plants until they have between five and seven nodes. By this time, they are usually strong enough to deal with a setback, although it’s important to continue to monitor them after topping for signs of poor health.

Topping is usually performed above the fifth node, enabling two new branches to develop from that point. When these are large enough, they too can be topped, although it’s necessary to wait several weeks between topping any growth so that the plant can recover fully from its previous ordeal.

Fimming, meanwhile, can begin slightly earlier in a plant’s life and is usually possible once three or four nodes have appeared. As with topping, fimming is something that can be repeated to continually multiply the number of colas. However, it is necessary to wait a few weeks before fimming any new growth to minimise the amount of stress placed on a plant.

It might sound obvious, but it bears mentioning that fimming and topping should only be performed during the vegetative stage of a plant’s growth. Once flowering begins, all stressful techniques must be halted so that plants can funnel all their energy into the production of that precious bud.

Finally, both topping and dimming should always be executed using a sharp blade. Pruning scissors, razors, and other cutting implements are suitable, but growers should ensure that their chosen instrument is as sharp as possible. Attempting to cut a plant with a blunt blade can cause the stem to break, increasing the amount of stress placed on a plant and potentially disrupting growth.

Many growers also choose to sterilise their cutting tools before filming or topping. This can be achieved using rubbing alcohol or by applying heat and is designed to prevent plants from becoming infected by killing any pathogens on the blade.

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

Ben Taub