Prune tomato plants in early summer when they are 12 to 18 inches tall, and continue removing suckers and lower leaves every one to two weeks through mid-August

Pruning tomato plants means removing specific parts—suckers (shoots that grow between the main stem and branches), lower leaves, and dead growth—to direct the plant's energy toward fruit instead of foliage. The timing and method depend on whether you have a determinate (bush) or indeterminate (vining) variety. Indeterminate tomatoes, which grow all season and produce fruit continuously, benefit most from regular pruning. Determinate varieties, which grow to a set size and produce most fruit at once, need less pruning.

Start pruning when the plant reaches 12 to 18 inches tall and has several sets of true leaves. At this stage, the plant is established enough to handle the stress of pruning. Continue pruning every one to two weeks through mid-August, then stop—late pruning removes leaves the plant needs to ripen remaining fruit before frost.

Key Takeaways

  • Prune indeterminate (vining) tomatoes regularly from early summer onward; determinate (bush) varieties need minimal pruning.
  • Remove suckers—the shoots growing between the main stem and branches—as soon as they appear, when they are still small and tender.
  • Strip leaves from the bottom 12 inches of the stem once the plant is 24 inches tall to improve air flow and reduce disease.
  • Stop all pruning by mid-August so the plant can focus energy on ripening fruit before the first frost.
  • Use clean, sharp pruners or pinch suckers off by hand to avoid spreading disease between plants.

Identifying and removing suckers

A sucker is a small shoot that grows in the crotch where a branch meets the main stem. Unlike a true branch, which produces flowers and fruit, a sucker produces only leaves and stems. Removing suckers redirects the plant's nutrients to fruit-bearing branches instead of wasting energy on leafy growth that shades the fruit and slows ripening.

Suckers are easiest to remove when they are 2 to 4 inches long and still tender. At this size, you can pinch them off with your fingers—grasp the sucker at its base and bend it sharply until it snaps. If you miss them and they harden, use clean pruning shears or a sharp knife to cut them as close to the main stem as possible. Sterilize your tool between plants by wiping the blade with rubbing alcohol or a 10 percent bleach solution (one part bleach to nine parts water) to prevent spreading disease.

On indeterminate varieties, check the plant every three to five days during the growing season. Suckers grow quickly in warm weather, and removing them while small prevents the plant from wasting resources. On determinate varieties, remove only the largest, most vigorous suckers—the plant's natural shape is bushier, and too much pruning will reduce your total harvest.

Removing lower leaves to improve air circulation

Once your plant reaches 24 inches tall, begin stripping leaves from the bottom 12 inches of the main stem. These lower leaves are the first to touch soil, collect splash during watering, and create a humid microclimate where fungal diseases like early blight and septoria leaf spot take hold. Removing them opens the base of the plant to air flow, which dries the leaves and soil surface faster after rain or watering.

Remove only healthy leaves at this stage—do not strip leaves that show spots or yellowing, as those are already infected and removing them will not stop the disease. Work from the bottom up, removing one or two leaves per week rather than stripping the plant bare at once. The plant needs leaves to photosynthesize and produce energy for fruit, so never remove more than one-third of the foliage in a single week.

Continue this practice through the growing season, always maintaining at least 12 to 18 inches of bare stem at the base. By mid-August, stop removing leaves entirely—the plant needs all remaining foliage to manufacture sugars that ripen the fruit still on the vine.

Removing diseased or dead growth

Remove any leaf or branch that shows signs of disease when ready, regardless of the season. Spots with concentric rings (early blight), small dark specks (septoria leaf spot), or fuzzy gray mold (botrytis) will spread to healthy tissue and other plants. Pinch off affected leaves or cut off entire branches with clean shears, and dispose of them in the trash—never compost diseased plant material.

Also remove leaves or branches that are completely yellow, brown, or dead. These no longer contribute to the plant's energy production and only take up space. Dead wood also harbors insects and disease spores, so clearing it out keeps the plant healthier overall.

If you notice a branch that is broken, damaged by wind, or rubbing against another branch, remove it entirely. A damaged branch will not recover and will only drain resources from healthy growth.

Timing your pruning through the season

Begin pruning in early summer when the plant is actively growing and the weather is warm. Warm temperatures help the plant heal quickly from pruning wounds. Avoid heavy pruning during heat waves above 85°F, as the plant is already stressed and pruning adds to that stress.

Prune in the morning on a dry day so any wounds dry quickly. Wet foliage and wet pruning tools spread disease more easily than dry ones. If you must prune on a wet day, sterilize your shears between every cut.

Taper off pruning in late July and August. As days shorten and temperatures cool, the plant shifts from growing new foliage to ripening fruit. Removing leaves at this stage removes the solar panels the plant needs to manufacture the sugars that make tomatoes sweet and flavorful. By mid-August, stop pruning entirely and let the plant focus on finishing the fruit already on the vine.

Pruning determinate versus indeterminate varieties

Determinate (bush) tomatoes grow to a fixed height—usually 3 to 4 feet—and produce most of their fruit in a concentrated window over two to three weeks. These varieties have a natural bushy shape and do not need aggressive pruning. Remove only dead leaves, diseased growth, and the most vigorous suckers that would otherwise shade the fruit. Light pruning keeps air flowing without reducing your harvest.

Indeterminate (vining) tomatoes grow continuously throughout the season and produce fruit until frost. They can reach 6 feet or taller and become dense with foliage that shades the fruit and slows ripening. These varieties benefit from regular, consistent pruning. Remove suckers as they appear, strip lower leaves, and thin out crowded branches to open the plant's interior to sunlight and air.

Check your seed packet or plant label to confirm which type you have. If you are unsure, indeterminate varieties usually have longer, thinner stems and produce fruit in clusters along the vine, while determinate varieties are stockier with fruit clustered at the branch tips.

Common pruning mistakes to avoid

Do not prune too aggressively early in the season. Removing too many leaves at once stresses the plant and slows growth. Remove no more than one-third of the foliage in any single week, and space pruning sessions three to five days apart so the plant can recover between cuts.

Do not use dull or dirty tools. Dull shears crush the stem instead of cutting cleanly, creating ragged wounds that heal slowly and invite disease. Dirty tools spread fungal spores and bacteria from plant to plant. Keep shears sharp and clean by wiping the blade with rubbing alcohol or a 10 percent bleach solution between plants.

Do not prune after mid-August. Late pruning removes leaves the plant needs to ripen fruit and prepare for dormancy. Fruit that loses its leaves before ripening will be pale, bland, and slow to mature.

Do not remove all the lower leaves at once. Strip a few leaves per week over several weeks rather than removing 12 inches of bare stem in a single session. Gradual removal lets the plant adjust without shock.

Frequently Asked Questions

Can I prune tomato plants on a cloudy or rainy day?

It is better to wait for a dry day. Wet foliage and wet pruning tools spread fungal spores more easily than dry ones. If you must prune in wet conditions, sterilize your shears between every single cut with rubbing alcohol or a 10 percent bleach solution to reduce disease spread.

What should I do with the leaves and branches I remove?

Throw diseased leaves and branches in the trash—never compost them, as the disease spores can survive composting and spread to your garden next year. Healthy prunings can go in the compost bin or yard waste bin if your community collects it.

Will pruning reduce my tomato harvest?

On indeterminate varieties, pruning increases your harvest by directing energy to fruit instead of foliage and improving air flow so fruit ripens faster. On determinate varieties, light pruning has little effect on total yield. Heavy pruning on determinate plants can reduce harvest, so remove only dead growth and the most vigorous suckers.

Is it okay to prune suckers off by hand instead of using shears?

Yes. When suckers are small and tender (2 to 4 inches), pinching them off by hand is fast and effective. Once they harden and thicken, use clean shears to avoid tearing the stem. Hand-pinching is gentler on the plant and spreads fewer diseases than using tools.

What if my tomato plant is already very tall and dense by mid-summer?

You can prune more aggressively on indeterminate varieties to open up the plant's interior. Remove entire branches that are shaded or crowded, and strip more lower leaves to improve air flow. On determinate varieties, focus on removing only dead or diseased growth and the lowest leaves. Avoid removing so much foliage that the fruit is exposed to direct sun, which can cause sunscald.