Remove suckers to direct energy into fruit, not extra stems
Suckers are the small shoots that grow in the V-shaped crease between the main stem and a branch. They look like miniature versions of the plant itself. Removing them is the single most useful trim you can make on a tomato plant, because every sucker you leave behind will grow into a full branch that produces leaves instead of fruit.
On indeterminate varieties (the tall ones that keep growing all season), suckers will eventually flower and fruit, but they delay the plant's energy from ripening the tomatoes already on the main stems. On determinate varieties (the compact bush types), suckers are less critical to remove, but doing so still improves air flow and makes harvesting easier.
Pinch off suckers when they are small—roughly 2 to 4 inches long—by hand or with pruning shears. The younger they are, the less the plant has to recover from the wound. Check your plants every 7 to 10 days during the growing season, because suckers grow quickly once they start.
Key Takeaways
- Suckers are shoots that grow between the main stem and branches; removing them sends more energy to fruit instead of extra foliage.
- Pinch off suckers when they are 2 to 4 inches long by hand or with clean shears, and check plants every 7 to 10 days.
- Remove the lowest leaves once the plant is 12 inches tall to reduce disease spread from soil splash and improve air circulation.
- Prune the top of indeterminate plants 4 to 6 weeks before your first frost date so the plant stops making new flowers and ripens existing fruit.
- Always use clean, sharp tools and remove only one-third of the plant's foliage at a time to avoid shocking it.
Remove lower leaves to stop soil-borne disease
Once your tomato plant reaches about 12 inches tall, begin removing the leaves that touch or hang close to the soil. Soil contains fungi and bacteria that cause common tomato diseases like early blight and septoria leaf spot. When rain or watering splashes soil onto those lower leaves, disease spores travel up the plant.
Remove leaves gradually—take off only the lowest 6 to 8 inches of foliage at first, then repeat every week or two as the plant grows. This slow approach prevents the plant from going into shock. Stop removing leaves once you reach the first flower cluster; the foliage above that point is doing the work of feeding the fruit.
Use clean pruning shears or scissors, and wipe the blade with rubbing alcohol or a 10 percent bleach solution between cuts if you are removing leaves from multiple plants. This prevents you from spreading disease from one plant to another.
Prune the top of tall plants before frost
Indeterminate tomatoes (varieties like 'Brandywine', 'Sungold', and 'Cherokee Purple') grow indefinitely and will keep flowering until frost kills them. About 4 to 6 weeks before your first expected frost date, pinch off the growing tip at the very top of the main stem. This stops the plant from making new flowers.
Why does this matter? Tomatoes take 20 to 30 days to ripen after they form. If you let the plant keep flowering right up until frost, those late flowers will never have time to mature into ripe fruit—they will just sit there green when cold weather arrives. By stopping new flowers early, you force the plant to focus all its energy on ripening the tomatoes already on the vine.
Mark your frost date on a calendar before the season starts so you do not forget. You can find your local first frost date through your county extension office or by searching "[your city] first frost date" online.
Thin dense foliage to improve air flow
Tomato plants with thick, crowded leaves stay wet longer after rain or watering, which creates ideal conditions for fungal disease. If your plant looks so dense you cannot see light through the canopy, remove some of the older, inner leaves to open it up.
Focus on leaves that are shaded by newer growth above them—these older leaves are not doing much photosynthesis anyway. Aim to remove no more than one-third of the plant's total foliage in a single week. Removing too much at once stresses the plant and can expose fruit to sunscald (a white or yellow patch where the sun burns the skin).
Better air flow also makes it easier to spot pests and disease early, and it gives you better access when harvesting ripe fruit.
Leave leaves above the fruit clusters alone
The foliage directly above your developing tomatoes is feeding them. Do not remove leaves just because they look old or slightly damaged unless they show clear signs of disease (dark spots, yellowing, wilting). A leaf with a small hole or minor blemish is still working and should stay on the plant.
The leaves are the plant's food factory. Every leaf you remove reduces the amount of energy the plant can make through photosynthesis, which slows fruit ripening and reduces the final size and sweetness of your tomatoes. Prune with purpose—remove suckers, remove diseased foliage, and thin for air flow—but do not strip the plant bare.
Use clean tools and prune on a dry day
Always use sharp pruning shears or scissors so you make clean cuts instead of crushing the stem. Crushed tissue is an open door for disease. If your shears are dull, sharpen them or replace them; a dull tool does more harm than a sharp one.
Prune on a dry day or in the morning after dew has dried. Wet foliage is more fragile and more prone to tearing. Wet leaves also spread disease spores more easily, so if you must prune a wet plant, clean your tools between every cut.
If you are removing diseased leaves, dispose of them in the trash, not in a compost pile. Many home compost piles do not get hot enough to kill tomato disease spores, so diseased leaves can infect next year's garden.
Frequently Asked Questions
Should I remove suckers on determinate tomato plants?
Determinate plants are naturally compact and produce most of their fruit in a short window, so removing suckers is less critical than on indeterminate types. That said, removing a few suckers still improves air flow and makes harvesting easier. If your determinate plant is small and manageable, you can leave the suckers alone.
Can I prune tomato plants in the middle of summer?
Yes, but avoid heavy pruning during the hottest part of summer (late July and August in most regions). Light pruning—removing suckers and diseased leaves—is fine anytime. Heavy pruning in extreme heat stresses the plant when it is already struggling with heat stress. Wait until early fall to do major thinning for air flow.
What if I accidentally remove a leaf cluster with flowers on it?
The plant will recover and make new flowers. One lost cluster is not a disaster. However, if you routinely remove large amounts of foliage, you will delay ripening and reduce your total harvest. Prune selectively and only when there is a clear reason—disease, dense shade, or sucker removal.
Do I need to seal the cuts after pruning?
No. Tomato plants heal their own wounds and do not need wound dressing or pruning sealer. In fact, sealing can trap moisture and promote rot. Just make a clean cut and let the plant handle the rest.
Can I use the suckers I remove to start new plants?
Yes. Suckers root easily in water or moist soil. Place a sucker in a glass of water on a sunny windowsill, and roots will form in 7 to 14 days. Once roots are 1 inch long, plant it in soil. This is a free way to grow extra tomato plants from varieties you already have.