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Training · Beginner · 1 min read

FIM: pinching most of the tip for multiple tops

FIM removes roughly 70–80 % of the newest growth at the tip instead of cutting cleanly above a node. When it works, three to five shoots grow from the same point; when it doesn't, you get one or two, like a sloppy top. It is less predictable than topping and has no controlled research behind its yield claims.

Grower practice
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VegAny system

Short answer. "FIM" is a partial top: pinch or snip off about 70–80 % of the newest, still-folded growth at the very tip, leaving the base of that tip. Often several tiny buds at the base grow out together, giving 3–5 new shoots from one point. Results are inconsistent; one or two shoots is common. The method is Grower practice: there is no controlled cannabis study of FIM vs topping. Topping gives a predictable result; FIM gives a gamble with more tops.

How to do it

  1. Plant with 4–6 nodes, healthy.
  2. Find the newest tight cluster of leaves at the main tip.
  3. Pinch or cut across it, removing the top ~¾ of the cluster; leave the bottom ~¼.
  4. Wait 5–7 days; the cluster should split into several shoots.
  5. Train the new shoots apart with LST.

Numbers that matter

Item Typical
Timing 4–6 nodes; can be repeated on new tops
Expected shoots 2–5 (variable)
Recovery Usually faster than a full top (Grower practice)
Last FIM before flip ≥ 7–10 days

Why it may work

The leftover tip tissue still contains several axillary meristems; damaging the dominant one without removing all of them can release more than two. Like topping, the yield benefit (where any) comes from a flatter canopy with more tops in good light [1][2].

Common mistakes

  • Cutting too little (the tip just regrows) or too much (it's just a top).
  • FIMing slow or stressed plants.
  • Expecting four colas every time.

Evidence

Apical dominance is Established. FIM-specific outcomes are Grower practice. Benefits of an even, well-lit canopy and of pruning are Supported [1][2].

Questions this article answers

What is FIMing?

FIMing is a cannabis training technique that pinches or snips off about 70-80% of the newest, still-folded growth at the main tip, leaving the bottom quarter in place. Done at 4-6 nodes on a healthy plant, the leftover tissue often splits into several new shoots within 5-7 days. It is grower practice, with no controlled cannabis research behind its yield claims.

FIM vs topping: which gives more colas?

FIM can give more colas than topping, typically 2-5 new shoots from one point versus topping's reliable two, but the result is a gamble. One or two shoots is common after FIM, while topping is predictable. No controlled cannabis study has compared them. Either way, any yield benefit comes from a flatter canopy with more tops in good light, not from the cut itself.

How much of the tip do I cut for FIM?

For a FIM, cut or pinch across the newest tight cluster of leaves at the cannabis plant's main tip, removing roughly the top three-quarters and leaving the bottom quarter. Cut too little and the tip simply regrows as one; cut too much and it becomes an ordinary top with two shoots. Wait 5-7 days to see the split, and leave at least 7-10 days before the flip.

Why did my FIM only grow one top?

A FIM that grows only one top usually means too little of the tip was removed, so the dominant growing point survived and simply regrew. Cutting too much instead gives an ordinary two-shoot top. FIM results are inconsistent even when done well, and slow or stressed plants respond poorly. You can FIM the new top again, since the technique can be repeated, or train it out with LST.

Sources

  1. Danziger N, Bernstein N, 2021. Shape matters: plant architecture affects chemical uniformity in large-size medical cannabis plants. Plants 10(9):1834. pmc.ncbi.nlm.nih.gov/articles/PMC8468686/
  2. Rodriguez-Morrison V, Llewellyn D, Zheng Y, 2021. Cannabis yield, potency, and leaf photosynthesis respond differently to increasing light levels in an indoor environment. Frontiers in Plant Science 12:646020. doi.org/10.3389/fpls.2021.646020

Related

SupportedBeginner · Draft

Topping: cutting the main tip for more colas

Topping removes the main growing tip above a node so the two shoots below take over, breaking apical dominance and producing a flatter plant with more main colas. Top healthy plants with 4–6 nodes, cut just above the chosen node, and allow 5–10 days of recovery before flipping to flower. In one controlled study, pruning twice (at transplant and at the switch to flower) gave the highest flower and cannabinoid yield per plant.

Grower practiceBeginner · Draft

LST: low-stress training

Low-stress training bends and ties stems outward and down so the plant grows as a flat, even canopy, without cutting anything. It is the safest training method, suits autoflowers, and works with topping and SCROG. Start in early veg, adjust ties every few days, and stop bending hard once stems lignify in mid-stretch.

Grower practiceIntermediate · Draft

SCROG: screen of green

SCROG uses a horizontal net 20–40 cm above the pots to spread a few plants into a flat, even canopy: shoots are tucked under the net through veg and early stretch, then allowed to grow up through it. It suits small rooms and plant-count limits, at the cost of longer veg. Fill about 70–80 % of the net before flipping, since plants stretch to fill the rest.

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