by Nebula Haze
“Fimming” (also known as FIMing) is a cannabis grow technique to increase yields. Discovered by mistake, this unusual plant training technique increases the number and size of cannabis buds. When the fimming is done right, of course. This marijuana fimming tutorial shows you how to fim plants perfectly every time.
Fimming refers to removing the top growth of a young cannabis plant, like this.
The result of successful fimming? 4 branches from one spot.
Fimming can help make more bushy, productive cannabis plants.
What to remember: The ultimate goal of fimming is to create a bushy plant with lots of main branches. This results in many big buds instead of only one.
What is fimming cannabis? Growers pinch off the top of a cannabis plant when it’s a few weeks old. When timed just right, plants naturally grow more top buds once the plant starts flowering. The fimming process causes a plant to naturally grow more wide and bushy as it develops. When growing cannabis indoors, creating a wide, flat plant is key to getting the biggest yields from your setup. Fimming naturally helps create that ideal plant shape for you.
A freshly “fimmed” cannabis plant.
Does fimming increase cannabis yields?
Yes, usually. The results of fimming range from “no effect” to “very effective”, depending on whether it’s done correctly. The bonus of basic fimming is growers can’t really do it wrong. The worst that can happen is no effect. But if you follow this fimming tutorial, your cannabis yields consistently get a yield boost.
Is fimming better than “topping”?
“Topping” is a similar technique to fimming, also to increase cannabis yields. The difference is topping means removing the whole top of the plant. Fimming means pinching off a small amount of growth.
Both methods are effective to make plants grow bushy and produce lots of big buds. Topping consistently splits the main stem into two, but you can accidentally stunt plants if you do it at the wrong time. Fimming is less consistent, resulting in 1-4 stems coming from the same spot, though you should get all four when fimming is done right. If you fim cannabis plants wrong, the result is no effect, and you’ll have the same single main stem as before. You can’t stunt a plant by simply fimming, but if you do it wrong, it doesn’t work and you don’t get any of the benefits.
Learn More: Topping vs FIMing Cannabis Tutorial
Why is it called “Fimming”? Fimming was discovered by mistake, and the name “Fim” reflects that history. The story goes that a cannabis grower tried to cut off the top of the plant, but didn’t do a complete job. But he liked the results better, and named the technique “FIM” for “F*ck I Missed”. Fimming was born.
How to “Fim” a Cannabis Plant
The main idea behind fimming is to “mow” off the top growth of your plant. The goal is to split the main stem into 4 stems with one strategic cut. A plant with 4 main stems is easy to train to grow wide and flat with simple bending. When done right, fimming cannabis can give results somewhat similar to time-intensive manifolding without adding weeks onto your grow time.
Wait until plant has grown 3-5 sets of leaves. At the right time, you’ll noticed all the lower stems are starting to grow into little branches. Yes, it’s not just about the total number of leaves, but also the overall size of the plant. If a plant is still tiny and thin, you should wait even if it’s got plenty of sets of leaves.
Too small to fim – even though this has 3 sets of leaves, the plant is tiny. The lower growth has not started growing away from the stem yet. Wait until plant gets a bit bigger or it may get stunted from fimming.
Beginning of fim window – This plant is just barely big enough to fim. The lower branches are just starting to grow away from the main stem. You might get better results by waiting just a bit longer.
Ideal size to fim – A cannabis plant about this size is the perfect size to fim. It’s got about 4 sets of leaves, and the lower growth is starting to grow away from the main stem into little branches of their own.
End of fimming window – This seedling has 5 full sets of leaves, starting on the 6th. This is about as big a cannabis plant should be when you fim. If your plant is bigger than this (and still in the vegetative stage), you should use the “topping” technique instead of fimming. To top a plant, cut through the main stem right above the 5th set of leaves (check out the full topping tutorial).
Right after fimming your young cannabis plant, it should have a “mowed” top left behind. Look at the above diagram to try to make sure you’re cutting through at the best spot.
Look at your plant and compare to the diagram above.
Remove this much growth to “fim” a cannabis plant.
Leave this much behind.
When done right, fimming results in 4 stems coming from essentially the same spot on the cannabis plant. However, fimming is not always the most consistent. Instead of 4 tops, if you don’t cut at the right spot you might end up with 1, 2, or 3 tops instead of all 4. If you want total control with perfect symmetry, check out the “topping” technique instead.
It’s normal for the new growth right after fimming to look weird. Remember, you cut off 80% of these leaves before they got a chance to grow out! If you damage a young leaf, it becomes more and more obvious as the leaf grows. However, brand new leaves after these ones should look normal.
A few days later, those mowed leaves from fimming should look a bit funny growing in.
Plants that have been fimmed naturally grow more bushy, which helps maximize yields in the flowering stage.
However, to improve your results, bend over tall branches. Just regularly bend the tallest stems down and away from the center of the plant, and tie them down. This process is known as Low Stress Training, or LST for short.
Keep bending tall stems down, so plant grows wide and flat.
The result? Tons of buds at harvest time!
Advanced Technique: Remove all stems but the top 4 (Serious Fimming)
Some growers take their fimming to the next step. Instead of just splitting the stem into 4 and letting the plant grow naturally, some growers remove all the other stems on the plant. In other words, they remove all steps but the top 4 they want to keep.
A fimmed cannabis stem. All but the top 4 stems were removed off the main “trunk”. Source: Nugbuckets
This makes it so all branches come from essentially the same spot on the cannabis plant.
Another example of a cannabis plant that was fimmed and all other branches removed. Source:Tarzan
However, if you want to go this direction, you may enjoy a more consistent plant training technique known as manifolding.
Learn how to manifold your cannabis plants.
Manifolding – better than fimming for cannabis growers who want symmetry.
Now you know how to fim your cannabis plants, so you get bigger yields at harvest time!
Want to learn about other marijuana plant training techniques to increase yields? Check this out!
Complete Guide to Cannabis Plant Training Techniques
