What Suckers Are and Why You Remove Them
Suckers are the small shoots that grow between the main stem of a tomato plant and its branches. They sprout from the joint where a branch meets the central stem, and if left alone, they grow into full branches that steal water and nutrients from the fruit-bearing parts of the plant. Removing them—called "suckering"—directs the plant's energy toward producing larger, riper tomatoes instead of extra leafy growth.
Not every tomato variety needs suckering. Determinate varieties (bush types that grow to a set size and fruit all at once) rarely need it. Indeterminate varieties (vining types that grow taller and produce fruit all season) benefit most from suckering because they have the energy and time to waste on extra growth. If you grow indeterminate tomatoes and want bigger fruit, suckering is worth the few minutes of work per week.
Key Takeaways
- Suckers are shoots that grow between the main stem and branches; removing them sends more energy to fruit production.
- Start suckering when suckers are small and tender, ideally when they are 2 to 4 inches long and straightforward to snap off by hand.
- Pinch or cut suckers at their base where they meet the main stem, leaving no stub behind.
- Sucker indeterminate (vining) tomatoes weekly during the growing season; determinate (bush) varieties rarely need it.
- Stop suckering about four weeks before your first frost date so the plant can focus on ripening remaining fruit.
When to Start Suckering and How Often
Begin suckering when the plant is 12 to 18 inches tall and has developed its first true branches. At this stage, suckers are small enough to remove without stressing the plant. Check your plants once a week during the growing season—suckers grow quickly in warm weather and can become woody and harder to remove if you wait too long.
The best time to sucker is early morning when the plant is firm and full of water. Avoid suckering in the heat of the day or when the plant is wet from rain or watering, because the plant is more fragile then and you risk spreading disease. If your hands or tools are dirty, wipe them on a clean cloth between plants to avoid passing fungal or bacterial problems from one plant to another.
How to Identify and Remove Suckers Correctly
Suckers are smaller and thinner than the main branches they grow from. They emerge at a sharp angle from the stem, right where a branch joins the main stalk. Once you spot one, pinch it off with your thumb and forefinger if it is still tender and small (2 to 4 inches long). Snap it downward and away from the stem in one quick motion—it should break cleanly.
If the sucker is thicker or woody, use a clean knife or pruning shears to cut it as close to the base as possible. Leave no stub sticking out, because a stub can regrow into another sucker. Cut at a slight angle so water runs off the wound instead of pooling on it. Do not worry about sealing the cut with wound dressing—tomato plants heal fine on their own, and dressing can actually trap moisture and invite rot.
Be careful not to remove the main branches by mistake. Main branches are thicker, grow at a wider angle from the stem, and have leaves and flower clusters on them. Suckers are always thinner and grow from the crotch between the stem and a main branch. If you are unsure, leave it alone and check again in a few days—a sucker will keep growing, while a main branch will not.
Common Mistakes That Damage the Plant
The most common error is suckering too aggressively. Removing more than one-third of the plant's growth at once stresses it and can slow fruit production. Sucker a little bit each week instead of waiting and removing a lot at once. This keeps the plant healthy and lets it adjust gradually.
Another mistake is suckering too late in the season. Stop suckering about four weeks before your first expected frost date. At that point, the plant should focus all its energy on ripening the fruit already on the vine rather than growing new branches. Suckering late in the season delays ripening and wastes the plant's remaining strength.
Do not sucker the very top of the plant (the growing tip). That tip is where new flowers form, and removing it stops the plant from producing more fruit. Sucker only the shoots that grow from the joints along the main stem and branches, never the central leader at the top.
Tools You Can Use
Your fingers are the best tool for small, tender suckers. Pinching by hand is fast, causes minimal damage, and you can feel exactly where the sucker meets the stem. For thicker suckers, a sharp knife or a pair of bypass pruning shears works well. Bypass shears (the kind with two blades that pass each other like scissors) make a cleaner cut than anvil shears (the kind with one blade that presses down onto a flat surface).
Keep your tools clean. Wipe the blade with a cloth or paper towel between plants, or dip it in a 10 percent bleach solution (one part bleach to nine parts water) if you are moving between plants that showed disease symptoms. Clean tools take only a few seconds and prevent spreading problems like early blight or septoria leaf spot from one plant to another.
Suckering Indeterminate Versus Determinate Varieties
Indeterminate tomatoes (varieties like 'Brandywine', 'Cherokee Purple', 'Sungold', and most heirloom types) grow as tall vines and produce fruit all season long. These varieties benefit most from suckering because they have months to regrow branches and can afford to lose the extra growth. Sucker them weekly throughout the season until four weeks before your first frost.
Determinate tomatoes (varieties like 'Roma', 'San Marzano', 'Mountain Magic', and most paste types) grow to a fixed height and produce most of their fruit in a short window. These plants are naturally bushy and do not need suckering. In fact, removing suckers from determinate plants can reduce your total harvest because you are removing branches that will bear fruit. If you grow determinate varieties, skip suckering altogether.
What Happens If You Do Not Sucker
If you leave suckers on an indeterminate tomato plant, the plant will grow bushier and produce more branches, but the fruit will be smaller and take longer to ripen. The plant spreads its energy across more leaves and branches, so each tomato gets less of the plant's resources. You will harvest more tomatoes by count, but fewer pounds of fruit overall, and the individual tomatoes will be less sweet and less flavorful.
Unsuckered plants also stay denser and shadier inside, which can trap moisture and create conditions for fungal diseases like early blight. Better air circulation around the plant (which suckering helps create) keeps leaves drier and reduces disease pressure. If disease is a problem in your garden, suckering is one way to improve air flow and lower risk.
Frequently Asked Questions
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 one to two weeks. Once roots are half an inch long, plant it in potting soil. You will have a new tomato plant that is genetically identical to the parent plant and will mature slightly earlier than a plant grown from seed.
What if I accidentally remove a main branch instead of a sucker?
The plant will survive and keep growing. You will lose some fruit from that branch, but the plant will redirect energy to the remaining branches. In the future, remember that main branches are thicker and grow at a wider angle, while suckers are thin and grow straight up from the crotch between the stem and branch.
Do I need to sucker cherry tomato plants?
Most cherry tomato varieties are indeterminate and will benefit from light suckering, but they are more forgiving than large-fruited types. If you want maximum fruit production and do not mind smaller individual tomatoes, you can skip suckering. If you want larger cherries and better air circulation, sucker them lightly once a week.
Is it okay to sucker when the plant is flowering?
Yes, you can sucker a flowering plant. Removing suckers will not harm the flowers or developing fruit. In fact, it improves air circulation around the flowers and fruit, which can reduce disease and help pollination. Just be gentle and avoid bumping the flower clusters.
What should I do with the suckers after I remove them?
Compost them if your compost pile gets hot enough (above 140°F) to kill any disease spores. If you are unsure about your compost temperature, throw them in the trash instead. Do not leave them on the ground near the plant, because they can harbor disease or pests.