How to


The FIM Technique

The FIM technique is a popular method of pruning used to help generate the growth of new colas on your cannabis plants. Technically known as floribunding, the acronym FIM is a long-running inside joke amongst growers, standing for “Fuck I missed!” was coined by an anonymous grower in the early 2000s who unintentionally created this modified topping technique by failing to remove the entirety of the main stem’s new growth. 

What remained was just the lower portion of the new growth, and the grower noted that the mistake generated four new, bushy colas from the main stem. Much to his delight, his plants thrived, and his yield increased. This success story has become commonplace amongst cannabis growers, and fimming has become standard practice.

What is the Fim Technique?

Considered one of many forms of super cropping, fimming is a high-stress training (HST) technique used to develop new, more abundant growth on cannabis plants. Often compared with topping, another HST technique involving a clean cut of all new growth, fimming involves the partial removal of new growth from the top of the main stem of your plant.

When fimming, the grower typically pinches or snips roughly 80% of the apical tip (the tip of new growth sprouting from the main stalk), leaving a small amount of the top growth at the base of the tip. In turn, the tip develops four new shoots (as opposed to the two produced by topping, or the one that will result from lack of pruning), resulting in a greater number of tops, each capable of producing its own dense, potent cola.

Marijuana plants tend to grow like Christmas trees, a pattern known as apical dominance. Fimming essentially turns this pattern on its head, transforming otherwise tall, lanky cannabis plants into short, squat monsters, perfect for producing thick, resinous buds. Rather than focusing its energy on growing one main cola, the plant will focus all of that same energy on developing thick stalks and side branches. Fimming lends itself well to the sea of green (SOG) method, wherein growers use training techniques to achieve a uniform canopy of top colas.

Fimming is especially perfect for home growers forced to grow in a small area such as a grow tent, though it doesn’t work as well with clones or autoflowering strains as with plants grown from cannabis seeds. Whether growing indoors or out, in soil or hydroponically, fimming is sure to produce some desirable results.

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Fimming vs Topping

Often compared with another form of super cropping, topping, fimming is a different practice with different results. Fimming originated as a failed attempt to top a plant, so it’s worth examining the two and noting the differing outcomes.

Topping involves the complete removal of the apical tip and can be thought of as the ultimate high-stress training technique. The entire new growth is removed at its base, forcing the plant’s growth hormones into lower stalks and branches.

As a result, topped plants will typically fork at the site of the topping, resulting in two strong new growths where there had previously been only one. This method is used to create short, squat plants that grow well in small indoor gardens and bear minimal resemblance to their unpruned, giant outdoor relatives.

Topping truly earns its reputation as a high-stress training technique, sending plants into a state of shock that can take days or even weeks to recover from. During this time, plants will dedicate growth hormones to recovery at the topping site and stalk development, resulting in stronger, more durable plants capable of withstanding more and producing greater harvests.

Fimming, by contrast, is less stressful to the plant than topping.

Fimmed plants have a much quicker recovery time, as the growth rate slows relatively little. In addition, plants that have been fimmed tend to “bush out” more than plants that have been topped; the lack of a distinct damage site causes the plant to push hormones into the general area that has been pruned, resulting in fuller, bushier development, rather than main cola development.

The question that often results from this comparison is, “Why would anyone choose topping over fimming?” Topping serves a specific purpose, as it is often the method employed at the beginning of supercropping. The two stalks which result from topping lend themselves well to various low-stress training (LST) techniques, such as bending and tying. These methods work well for fimming also, but with slightly different results.

When and How to FIM cannabis plants

Now that the benefits of fimming have become apparent, it’s important to know when in the life cycle of your plants fimming should occur. As with topping, it is best to wait until plants have outgrown the seedling stage and have entered the vegetative stage.

Of equal importance is to not wait too long into the vegetative stage to FIM your plant. It’s best to FIM when the plant has developed between three and five nodes (the sites on the stalk from which sets of leaves generate). Fimming too soon will slow growth to a standstill. Fimming too late will result in a top-heavy plant that cannot support itself.

When fimming, the grower removes only the top 75-80% of the plant’s new growth, leaving the remainder intact. Its unkempt appearance leads many to wonder if they’re doing it right, but the resulting four colas will provide the answer. Some growers prefer to use scissors to snip the tips, while others feel that pinching the growth with one’s fingers is the way to go. The main factor to consider is whether the cut will leave any openings for pests or disease.

Many growers prefer the pinch method because it essentially “seals” the tips of the new growth as it is performed. Whichever method you choose to employ in fimming your plants, it should be noted that fimming provides the most abundant harvests when coupled with other LST techniques.

Fimming a marijuana plant with large fan leaves

Fimming for Maximum Yield

Employing various pruning and LST techniques to your fimmed plants will undoubtedly increase your yields even more than fimming alone. A variety of methods work well along with fimming, and it’s important to understand which.

Bending: The stalks of fimmed plants can be bent in various configurations to help achieve maximum light exposure to lower areas of the plant.

Lollipopping: When lollipopping a plant, a grower removes lower branches to help focus growth into buds and colas. This works especially well with fimming as fimmed plants tend to be extra bushy, which can result in lots of small, lower branches that drain energy from the tops.

SCROG: The screen of green (SCROG) is a variation of the sea of green method that involves placing a net or trellis over your plants for them to grow into. The squares of the trellis provide support for heavily laden branches and colas, helping to prevent them from bending and breaking beneath the weight of all those beautiful, flavourful buds.

Defoliation: Removing a plant’s fan leaves will allow more light to penetrate deeper into the structure of the plant, resulting in denser, more potent buds. Of course, it’s crucial to keep defoliation in check. There are many stories of beginning growers defoliating their way to nothing but stalks.

Should I FIM My Plants?

Once the decision has been made to prune a plant, fimming boasts several benefits over other methods but comes with some minor drawbacks as well.

Benefits of fimming include:

Relatively low stress: Compared with other HST techniques, fimming is less stressful for the plant. Plants that have been fimmed will recover quickly and resume growth in a matter of hours, as opposed to plants that have been topped, the shock from which may take days to recover.

Generates more colas – Fimming will generate the growth of four or more new colas from the tip that is pruned. Topping, by contrast, will result in the creation of two new colas.

Bushier plants: Fimming, especially from the beginning of the vegetative stage, results in shorter, bushier plants that possess sturdy, strong branches capable of supporting numerous flower sites.

Repeatable – Plants can be continually fimmed during the vegetative stage, though pruning of any sort should be ceased once the flowering stage is reached.

Some drawbacks of fimming include:

Staking/SCROGging: Fimmed plants are often known to develop so many bud sites and colas that they can become top-heavy, requiring the grower to stake or SCROG the grow to ensure the plants don’t topple beneath the weight.

Longer vegetative stage: Fimming will shock your plants (albeit to a lesser extent than topping). This will result in a longer veg time. Flowering remains the same.

Ultimately, the decision to FIM is best left to the grower. Fimming will undoubtedly increase yields but may also result in a bushy plant that is hard to manage, which can become a problem in a grow tent or small grow room. Assuming the grow has enough space for fimming, the benefits far outweigh the drawbacks, resulting in beautiful canopies of gorgeous, sticky buds.

Post author
Michael Richey
Michael loves to grow cannabis and write about what he learns along the way. His best friends are his dogs and marijuana.
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