Pruning tomatoes is one of the most misunderstood tasks in the vegetable garden. Done correctly, it dramatically increases yield, improves fruit quality, and reduces disease. Done incorrectly — or skipped entirely — it produces a sprawling, unmanageable plant with small, late fruit. The key is understanding what type of tomato you are growing.
Determinate vs Indeterminate Varieties
Determinate tomatoes (also called bush tomatoes) grow to a genetically fixed height and set all their fruit over a short period. They should not be heavily pruned — removing growth reduces their overall fruit set. Prune only to remove diseased or damaged growth. Determinate varieties include Roma, Celebrity, and most paste tomatoes.
Indeterminate tomatoes (also called vining or cordon tomatoes) grow continuously and need training and pruning to direct energy into fruit rather than foliage. Almost all large-fruiting, beefsteak, and cherry tomato varieties sold as individual plants at garden centres are indeterminate. These are the plants that benefit most from regular pruning.
Removing Suckers
The key pruning task for indeterminate tomatoes is removing suckers — the shoots that grow from the axil (the junction between the main stem and a leaf branch). Left to grow, each sucker becomes a full stem with its own leaves, flowers, and fruit — but at the cost of slowing the development of existing fruit clusters. Pinch out suckers when they are small (under 5cm) by hand. Once they grow larger, cut cleanly with a knife or scissors to avoid tearing the main stem.
How Many Stems?
For cordon training (the most productive method), allow one main stem and remove all suckers. This concentrates energy into a single vertical column of fruit clusters. Two-stem training (allowing one sucker below the first flower truss to develop as a second main stem) is a valid approach in a short growing season where you want to hedge against early blight on the primary stem. More than two stems dilutes yield without proportional benefit.
Topping the Plant
Towards the end of the growing season — six to eight weeks before your first expected frost — pinch out the growing tip of the main stem. This stops the plant from producing new flower trusses that will not have time to ripen before cold weather. All energy goes into ripening existing fruit. This is called stopping the plant.
FAQ
If I remove suckers, will I get fewer tomatoes?
In the short term, yes — each sucker removed is a potential fruit-bearing stem. But in practice, the remaining fruit on the trained stem ripens earlier, grows larger, and the plant is healthier and more manageable. Total yield by weight is typically equal to or greater than an unpruned plant, with better quality.
What happens if I do not prune at all?
Indeterminate varieties will grow into a large, bushy plant with many small, slow-ripening fruit clusters. In a cool climate, many tomatoes will fail to ripen before the first frost. In warm climates, unpruned plants can still produce well but are harder to manage and more susceptible to disease.
Is it wrong to remove suckers once they are large?
It is better to remove them small, but it is never too late. Larger suckers leave a bigger wound on the main stem, so cut rather than snap to make a cleaner cut. The wound heals quickly in warm weather.
Should I remove lower leaves?
Yes — remove leaves below the lowest fruit truss as the season progresses. This improves airflow at the base of the plant, reduces soil splash (which spreads blight), and directs energy upward. Do not remove more than one-third of the foliage at any one time.
Can I prune cherry tomatoes the same way?
Yes, if they are indeterminate cherry tomato varieties (most are). Cherry tomatoes are naturally more vigorous than large-fruiting varieties and benefit from regular sucker removal and stem training. They are also more forgiving — missing a pruning session or two does not ruin the crop.
See also: Succession Planting for Continuous Harvests and Spring Planting Guide by USDA Zone.