Gardening glossary
Topping (FIM and main-stem topping)
Topping in a vegetable, herb, or cannabis context is the deliberate cut of the main growing tip to force the plant to branch into multiple stems. It is a slightly more aggressive version of [pinching](/glossary/pinching) — usually involving a clean snip with secateurs rather than a thumbnail squeeze, and removing more material from a more developed plant.
The mechanism is the same as pinching:
1. The main growing tip produces auxin, a hormone that suppresses the growth of axillary buds further down the stem. 2. Cut off the tip and the auxin signal disappears. 3. Within days, the suppressed buds wake up and shoot out as new lateral stems. 4. The plant becomes wider and bushier rather than taller and single-stemmed.
Where topping is used:
- **Indeterminate tomatoes.** Topping near the end of the season (4–6 weeks before first expected frost) redirects energy from new growth into ripening existing fruit. Cut the main stem just above the highest truss with set fruit. - **Peppers and chillis.** A first topping above the 5th–6th node when the plant is young creates a bushy, multi-stemmed structure that produces 30–50% more fruit than an untopped plant. - **Basil.** Top every 2 weeks above a lower node to keep the plant short and bushy and prevent flowering. - **Cannabis.** Topping (also called "FIMing" when only the top half of the new shoot is removed) is a routine technique to produce multi-cola plants from a single main stem. - **Many annual flowers** — cosmos, zinnias, snapdragons — benefit from a single topping early on.
How to top cleanly:
1. **Wait until the plant has at least 5–6 sets of true leaves.** Topping too early stunts growth. 2. **Cut just above a node** with sharp, clean snips. A clean cut heals fast and reduces disease entry. 3. **Top in cooler hours** (morning) for less transplant-style shock. 4. **Allow recovery time.** Most plants need 5–10 days to push out new lateral shoots before they look right again.
**Important distinction: tree topping is harmful, not the same as this.** When arborists or homeowners "top" a mature tree by removing the entire crown to short stubs, the tree usually responds with weak, poorly-attached suckers that fail in storms, often becoming a hazard. Mature unpollarded trees do not bounce back from topping the way an annual herb does. If you want to keep a tree small, use proper [pollarding](/glossary/pollarding) from when the tree is young, or choose a smaller species in the first place.