How to Prune Tomatoes (and When Not To)

Pruning a tomato is mostly about one thing: deciding which suckers to pull. A sucker is the new shoot that sprouts where a leaf meets the main stem, and left alone it grows into a whole second stem with its own leaves, flowers, and fruit. Whether you remove them depends entirely on what kind of plant you have. Prune the wrong type and you just throw away fruit.

What a sucker is

A sucker is a new shoot that develops in the leaf axil, the crotch where a leaf branches off the main stem. Each one, if you let it, becomes a full second stem. Pinching them out is what most people mean by pruning a tomato.

The decision is not about tidiness, it is a tradeoff. Fewer stems means fewer but larger and earlier fruit and better airflow. More stems means more total fruit on a bushier, leafier plant.

Determinate plants: leave them alone

Determinate tomatoes are bushes that grow to a fixed size, around four feet, set their fruit, and stop. On these, do not prune the suckers. University of Illinois Extension is blunt about it: determinate varieties are not heavily pruned because most of the fruit is produced on those branches, so removing them just removes your harvest.

The one thing you can safely take off is the foliage right at the bottom, the leaves and shoots below the first flower cluster that sit close to the soil. Beyond that, let a determinate grow.

Indeterminate plants: prune to one or two stems

Indeterminate tomatoes are vines that keep growing and fruiting until frost, and these are the ones pruning helps. UNH Extension recommends training to a single leader as the most common approach: pick the main stem and remove all the suckers, so the plant puts its energy into one strong vine.

If you want a little more fruit and a fuller plant, train to two leaders instead. Keep the vigorous sucker just below the first flower cluster as your second stem, and remove all the others. How hard you prune also tracks how you support the plant: Illinois Extension notes indeterminate plants are heavily pruned when trellised, moderately when staked, and lightly when caged.

How and when to pinch

Remove suckers while they are small, under about two inches, when they snap off cleanly with your fingers. Pinch them by hand rather than cutting, since Illinois Extension warns that a knife moving from plant to plant can spread disease. A large, established sucker also tears a bigger wound when it comes off, so stay ahead of them and check the plant every few days.

Strip the lower leaves too. Keep the leaf just below the lowest fruit cluster and everything above it, and remove the foliage below that. Those bottom leaves are the ones rain splashes soil onto, and they are the usual entry point for disease.

What pruning actually buys you

Here is the honest version of the tradeoff. Pruning an indeterminate plant gives you larger, earlier, cleaner fruit, but less of it by total weight. UNH Extension puts it plainly, that removing suckers reduces potential yield while increasing airflow and improving the fruit you do harvest. Illinois Extension adds that a pruned plant channels its energy into the fruit, so what ripens is bigger and comes sooner.

The airflow is the quiet benefit. An open, single-stemmed plant dries faster after rain, which UNH ties to fewer fungal problems like early blight, Septoria leaf spot, and anthracnose. In a wet summer that can matter more than the size of any one tomato.

Want the flavor on a specific tomato, not a color rule?Find your tomato

Common questions

Do I need to prune tomatoes at all?
Only indeterminate (vining) types, and even then it is optional. Determinate (bush) types should not be pruned beyond the lowest leaves, because most of their fruit grows on the suckers you would be removing.
How do I tell a sucker from a real stem?
A sucker grows in the axil, the V where a leaf meets the main stem. Fruit clusters grow off the stem itself, not from that crotch. When in doubt, leave it until you see whether it makes a flower truss.
Will pruning give me more tomatoes?
Not more by weight. Pruning an indeterminate plant trades total quantity for larger, earlier fruit, better airflow, and fewer disease problems. If you want maximum total fruit, prune less.
Which of my tomatoes is determinate or indeterminate?
Every profile on this site lists the habit in its grow-trait card, and the browse filters and chooser let you sort by it. As a rule, most paste and patio types are determinate; most heirlooms and cherries are indeterminate.

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