Yes, you should prune most tomato plants, but the method depends on the type you're growing
Pruning tomato plants is not required to get fruit, but it improves air flow, reduces disease, and directs the plant's energy toward producing larger tomatoes instead of excessive foliage. The catch is that determinate (bush) tomatoes and indeterminate (vining) tomatoes need different approaches. Indeterminate varieties—the ones that grow tall and keep producing all season—benefit from regular pruning. Determinate varieties, which grow to a set size and produce most fruit at once, need little to no pruning because removing growth reduces your total harvest.
The most common pruning task is removing suckers, the small shoots that grow between the main stem and branches. These steal nutrients without producing fruit. On indeterminate plants, removing suckers funnels energy into the main stem and side branches that actually bear tomatoes. On determinate plants, leave the suckers alone unless the plant is so dense that air cannot move through it.
Key Takeaways
- Indeterminate (vining) tomatoes should be pruned regularly to remove suckers and improve air flow, while determinate (bush) tomatoes need little pruning because removing growth reduces total yield.
- Suckers are small shoots between the main stem and branches; removing them on indeterminate plants directs energy to fruit-bearing branches.
- Prune in the morning when the plant is firm, use clean pruners or your fingers, and remove no more than one-third of the plant at a time.
- Stop pruning indeterminate plants about four weeks before your first expected frost so the plant can focus on ripening existing fruit rather than new growth.
How to identify suckers and where to remove them
A sucker grows at a sharp angle where a branch meets the main stem—usually around 45 degrees. The main stem and branches grow more vertically. Suckers are thinner than the branches and have their own small leaves. If you are unsure whether something is a sucker, leave it; a mistake costs less than removing a fruit-bearing branch.
On a young plant, you can pinch suckers off with your fingers when they are small and tender. On larger plants or woody growth, use clean pruning shears or a sharp knife. Sterilize your tool with rubbing alcohol or a 10 percent bleach solution (one part bleach to nine parts water) before you start, and again between plants if you are pruning multiple tomatoes. This prevents spreading disease like early blight or late blight from one plant to another.
The difference between pruning indeterminate and determinate varieties
Indeterminate tomatoes grow like vines and will keep producing fruit until frost kills them. These plants benefit from aggressive sucker removal because they have the season to regrow and produce more fruit on the main branches. Remove suckers throughout the growing season, starting when the plant is about 12 inches tall. You can also remove the lowest leaves once the plant is established—this improves air flow near the soil where disease spores live.
Determinate tomatoes are bred to grow to a fixed height and produce most of their fruit in a short window. Removing suckers removes potential fruit sites, so you lose yield. Leave determinate plants alone unless they are so overgrown that leaves are touching the ground or the center is so dense that water cannot dry after rain. If you do prune, remove only the lowest leaves and leave all the suckers.
When to stop pruning before harvest
Stop removing suckers about four weeks before your first expected frost date. At that point, the plant should focus its energy on ripening the fruit already on the vine rather than growing new branches and flowers that will not mature before cold weather arrives. If you live in a warm climate with a long season, you can prune longer, but the principle is the same: give the plant time to finish the fruit it has already started.
You can continue to remove the lowest leaves throughout the season to improve air flow, but do not remove more than one-third of the plant's foliage at a time. The leaves feed the plant and produce the sugars that make tomatoes taste good. Removing too much at once stresses the plant and can expose fruit to sunscald if leaves that were shading it are suddenly gone.
Tools and timing for safe pruning
Prune in the morning when the plant is firm and full of water. Tomato stems are easier to cut cleanly when they are not wilted, and a clean cut heals faster than a ragged break. Use sharp pruning shears, a clean knife, or your fingers for small suckers. Dull tools crush the stem instead of cutting it, which invites disease.
Do not prune when the plant is wet from rain or overhead watering. Moisture on the leaves spreads fungal spores and bacteria. Wait until the foliage dries, usually a few hours after rain or watering. If you are pruning multiple plants, clean your tool between each one to avoid spreading disease from a sick plant to a healthy one.
What happens if you do not prune at all
Indeterminate tomatoes that are never pruned will still produce fruit, but the plant becomes dense and bushy. Poor air flow traps moisture and creates conditions for early blight and late blight, fungal diseases that start on lower leaves and spread upward. The plant also puts energy into growing leaves and suckers instead of enlarging the fruit you already have, so tomatoes tend to be smaller. You will harvest more total fruit from an unpruned plant, but the individual tomatoes will be less impressive.
Determinate tomatoes do not need pruning and will produce a full crop without it. If anything, pruning them reduces your harvest because you are removing branches that would have borne fruit. The only reason to prune a determinate plant is if it is so overgrown that you cannot reach the fruit or air cannot move through it.
Common pruning mistakes to avoid
The biggest mistake is removing too much at once. Tomato plants need leaves to photosynthesize and feed themselves. If you strip away more than one-third of the foliage in a single session, you stress the plant and slow growth. Spread pruning over several weeks instead of doing it all at once.
Another mistake is pruning determinate plants aggressively. These varieties are bred to produce most of their fruit in a concentrated window, and removing suckers removes fruit sites. If you have a determinate plant, leave it alone unless the foliage is so dense that it is touching the ground or the center is completely shaded.
Do not prune too late in the season. Pruning stimulates new growth, and new growth that appears close to frost will not have time to mature. Stop pruning about four weeks before your first expected frost so the plant can finish ripening the fruit it has already started.
Frequently Asked Questions
Can I prune tomato plants in the afternoon or evening?
Morning is better because the plant is firm and full of water, making cuts cleaner and faster to heal. Afternoon pruning works if you must, but avoid pruning when the plant is wilted from heat or when foliage is wet from rain or watering.
What if I accidentally remove a branch with fruit on it?
The fruit will not ripen on the branch once it is cut. If the tomatoes are already full-sized and starting to turn color, you can ripen them indoors in a paper bag or on a windowsill. If they are still small and green, they will not develop further and should be discarded.
Do I need to seal the cut with wound dressing or paint?
No. Tomato plants heal cuts on their own, and wound dressing can actually trap moisture and invite disease. A clean cut is all you need. The plant will form a callus over the wound within a few days.
How do I know if my tomato is determinate or indeterminate?
Check the seed packet or plant label—it should say "determinate" or "indeterminate." If you have lost the label, indeterminate plants grow tall and keep producing fruit all season, while determinate plants stop growing at a set height and produce most fruit in a short window. Determinate plants are usually bushier and more compact.
Can I use the suckers I remove to grow new tomato 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 appear in one to two weeks. Once roots are half an inch long, plant it in soil. This is a free way to grow extra plants, though they will mature later than plants started from seed.