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harvestUpdated Apr 2026

How and when do I prune suckers on indeterminate tomatoes?

Remove suckers — the shoots that emerge in the crotch between the main stem and a branch — while they're still small, before they reach finger-width, to maintain a manageable plant structure without creating large wounds.

A sucker is a shoot that grows from the axil — the V-shaped crotch between the main stem and a leaf branch. Left in place, every sucker becomes a full branch with its own suckers, and the plant sprawls into a large, difficult-to-manage structure. On indeterminate varieties (which grow and set fruit continuously rather than all at once), pruning to one or two main stems keeps the plant on a trellis or stake, improves airflow, and tends to produce fewer but larger fruit earlier in the season. On determinate varieties, which grow to a fixed size and set most of their fruit within a concentrated window, removing suckers is generally not recommended — it reduces yield.

Timing matters. Suckers removed when they are under an inch long break off cleanly with fingers, leaving almost no wound. Suckers over an inch require cutting and leave a larger wound that takes time to heal and can invite disease in wet conditions. Make cuts close to the main stem without cutting into it; leaving a tiny stub is fine and heals over. Removing large suckers in wet, humid weather increases the risk of fungal infection at the cut site. On very productive plants in mid-season, it may make sense to leave a sucker that has already set fruit rather than remove it late — the energy trade-off shifts once fruit is already forming.

Most growers on a stake-and-string or cage system aim for one to two main stems. Two main stems — the original growing tip plus one early sucker kept and trained alongside it — give good yield without excessive complexity. Beyond two stems, management becomes difficult and airflow through the canopy decreases. Check plants every 5–7 days during the active growing season; suckers grow fast in warm weather and can go from pinchable to finger-thick in a week.

Pruning changes the character of the harvest: fewer fruit overall, but each one gets more of the plant's photosynthetic output and tends to be larger and may ripen somewhat earlier. Unpruned plants often produce more total fruit by weight over the season, but the harvest is spread across many stems and airflow is worse. Neither approach is inherently superior — it depends on whether you're growing for a long, extended harvest or for an earlier, concentrated yield. In climates with short growing seasons, aggressive single-stem pruning can help get fruit to size and ripeness before the first frost.

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