Want better tomatoes? Learn to prune them. Done right, pruning and staking give you larger fruit sooner, plants that dry faster after rain, and a tomato bed you can actually work.
The Connecticut Agricultural Experiment Station says a pruned and staked plant produces larger fruit two to three weeks earlier than one left sprawling on the ground.
One thing worth knowing before you grab the pruners: pruning is a choice between more, smaller tomatoes and fewer, larger ones.
In Connecticut, more stems generally mean more but smaller fruit, produced increasingly later in the season. Fewer stems means fewer but larger fruit. This guide walks you through those choices.
The right tool helps. The Felco #2 pruner has been in our hands for more than 40 years.
Related: Learn why in our article on the Felco F-2 Classic Manual Hand Pruner
First, Know Which Type Of Tomato You Have
Pruning rules depend on whether your tomato is determinate or indeterminate, so check the plant tag or seed packet before you cut anything.
Determinate tomatoes have a bush habit. University of New Hampshire Extension says they stop growing once they set a terminal bud, usually around 4 feet tall, and give a short, defined harvest season.
(NC State Extension puts them at about 3 feet.) Indeterminate tomatoes keep growing until frost and keep setting flowers and fruit the whole time. UF/IFAS says they may reach 10 feet or more if conditions are perfect.
Go easy on determinate tomatoes. The Connecticut Agricultural Experiment Station says they need no pruning other than removing all suckers below the first flower cluster, and that any pruning above that cluster throws away potential fruit. Iowa State University Extension agrees: yields do not increase by removing suckers beyond the first flower cluster.
Indeterminate tomatoes are the ones to prune. Iowa State says to keep removing suckers as they form, all along the main stem, throughout the growing season.
Get Support In Place From The Start
Indeterminate plants get tall and heavy, so put your support in when you plant. UF/IFAS recommends staking tomatoes to keep the fruit off the ground, then tying the plants to the stakes at a few different heights just below the fruit clusters.
Stakes, a high trellis, or twine woven between stakes all work. Clemson Extension calls the twine method the Florida weave.
A well-supported plant is also easier to read. You can see the main stem, the fruit clusters and the suckers, so you can plan each cut instead of guessing.
Related Reading: Epsom Salt For Tomatoes: What It Actually Does (and When to Use It)
Related Reading: Tomato Growing Dos & Don’ts
What About Tomato Cages?
You won’t want to use tomato cages like these for tall indeterminate plants, because the cages tend to hold all of the limbs together. That makes it hard to see which shoots need pruning and which should stay.
The extension guides back up the general point. Connecticut says ready-made tomato cages are too small for all but the smallest determinate varieties, and UF/IFAS says large cages may not be enough for an indeterminate tomato you don’t prune.
Cages do work well for plants with three to five stems, says Connecticut, and are especially useful for determinate types. Clemson Extension says caged plants are usually pruned just once, to three or four main stems.
What Pruning Does (and What It Doesn’t)
Pruning changes where the plant puts its energy. Iowa State says it helps plants direct more energy to flowering and fruiting. Extension sources describe suckers a little differently.
Iowa State says they are mostly leafy growth that produces little, if any, fruit, while Connecticut says a sucker left alone grows just like the main stem and produces flowers and fruit. Connecticut adds that extra stems divert some of the plant’s sugar production from fruit to extra growing tips.
Pruning and support also help with disease. Connecticut says leaves on pruned and supported plants dry off faster, so bacterial and fungal pathogens have less opportunity to spread, and upright plants have fewer problems with leaf spots and fruit rots.
Iowa State says removing suckers can open the canopy for better air circulation. That can mean fewer fungal diseases to worry about.
It saves space, too. Left alone, Connecticut says, a vigorous indeterminate plant can easily cover a 4- by 4-foot area with as many as 10 stems. For staked plants, Connecticut suggests spacing of 18 inches for a single stem, 24 inches for two stems, and 36 inches for three or four stems.
Related: Learn more about How Far Apart to Space Tomatoes.
Does pruning mean a bigger harvest? Not guaranteed. UF/IFAS says removing and pruning tomato shoots promotes more flower growth, resulting in greater fruit production, and University of New Hampshire Extension says pruning can improve harvestable yields and prolong the harvest season.
But UNH also says removing suckers reduces potential yields while increasing airflow, and Connecticut says more stems means more but smaller fruit. Think of pruning as a trade: larger, earlier fruit and healthier plants, with the total count depending on how many stems you keep.
Don’t overdo it. Iowa State says you don’t need to remove every sucker, especially if it leaves the leaf canopy very open, because exposed tomatoes can get sunburn or sunscald. It also says to avoid removing more than one-third of the plant’s foliage at a time. NC State says to leave the leaves that shade the fruit.
How To Prune Indeterminate Tomatoes, Step By Step
- Start with clean, sharp tools. Iowa State says to disinfect your hands and pruning equipment, and to clean them between plants or every few plants, to help prevent disease from spreading. These are our favorite pruners.
- Prune when the leaves are dry. Connecticut rules say to avoid pruning or tying plants when the leaves are wet, and Iowa State also recommends pruning on a dry day.
- Find the sucker. Follow the main stem up to a spot where a compound leaf joins it. Iowa State says the new stem growing in between is the sucker.
- Pinch it off while it is small. University of New Hampshire Extension says under 2 inches, NC State says no more than 2 to 4 inches, and Iowa State says less than a few inches. Snap it off with your fingers. Connecticut says a knife or scissors can easily cut a stump, and that once a sucker is too tough to snap, you need a blade. Iowa State says to cut cleanly and not leave a jagged wound.
- Keep the space below the first flower cluster free of side stems. Connecticut says that is best.
- Choose how many main stems to keep. UF/IFAS recommends leaving two to three main stems, Clemson Extension recommends one or two (or three or four for caged plants), and Connecticut says indeterminate tomatoes can have one to as many as four. Pick a number, then remove the other suckers as they appear.
- Protect the growing tip. Connecticut says to avoid the top 10 inches of the stem when removing suckers so you don’t take off the growing tip.
- Leave the leaves that shade the fruit. NC State says newly exposed tomatoes can often suffer sun scald.
Snapped-off suckers don’t have to go in the compost. Clemson Extension shows in a short video how to root them into new plants.
Missouri Pruning: A Gentler Option For Big Suckers
If a sucker gets away from you, try Missouri pruning. According to the Connecticut Agricultural Experiment Station, pinch out just the tip of the sucker and leave one or two leaves.
The upside is more leaf area for photosynthesis and better protection for the developing fruit from sunscald. The downside is that new suckers inevitably develop along those side stems, which means more pruning later.
Connecticut says this is the better move when suckers are already large. Removing just the tip shocks the plant less than removing a foot or so of side stem, and if disease hits, it is farther from the main stem.
Keep The Bottom Of The Plant Clean
The lower leaves get splashed. NC State and Iowa State both recommend removing leaves and side shoots from the bottom 6 to 12 inches of the plant, especially anything that touches or comes close to the soil.
NC State says this keeps soil-borne diseases from splashing up when raindrops hit the ground, and Iowa State adds mulch around the base to reduce soil splash further. That helps against soil-borne problems such as early blight and Septoria leaf spot. Learn more in our guide to tomato blight.
Top Your Plants Late In The Season
Near the end of the season, topping helps the fruit you already have ripen. Iowa State says that removing the growing tip of the main stem directs more energy into maturing the existing fruit instead of making new leaves, flowers, and stems.
Do it about four to six weeks before your average first fall frost date. Cut the main stem just above a leaf or a fruit cluster, in dry weather.
Timing matters. Iowa State says topping too early can reduce overall plant growth and yields, and that topping determinate tomatoes at any stage will significantly reduce their yields.
Iowa State also suggests removing flowers as they appear, starting about four weeks before the first fall frost, to help late-season ripening.
Final Thoughts
Pruning tomatoes is a set of choices. One or two stems for larger fruit, or more stems for more, smaller ones. Leave determinate types mostly alone, and prune indeterminate types early and often, while the suckers are still small.
Skipping pruning altogether is one of the tomato-growing mistakes we cover in another guide, and our high-yield tomato guide takes in the rest of the growing season.
Related: our guide to natural tomato fertilizers. How many stems are you growing this year, one or two? Tell us in the comments.
Frequently Asked Questions
Should you prune determinate tomatoes?
Only a little. The Connecticut Agricultural Experiment Station says determinate tomatoes need no pruning other than removing all suckers below the first flower cluster, and that pruning above it throws away potential fruit. Iowa State University Extension agrees that yields do not increase by removing suckers beyond that cluster. Save your serious pruning for indeterminate varieties.
When should you remove tomato suckers?
While they are small. University of New Hampshire Extension says under 2 inches, and NC State Extension says no more than 2 to 4 inches. Snap them off with your fingers, because Connecticut says a stump left by a knife or scissors can easily become infected. Prune when the leaves are dry.
Will pruning give you more tomatoes?
Not always. Pruning and staking together tend to give larger fruit sooner. Connecticut says a pruned and staked plant produces larger fruit two to three weeks earlier than one left on the ground, and that fewer stems means fewer but larger fruit. University of New Hampshire Extension says pruning can improve harvestable yields, so expect a trade between size and count.
How many stems should you leave on a tomato plant?
It depends on your method. UF/IFAS says to leave two to three main stems on indeterminate tomatoes. Clemson Extension says one or two, or three or four for plants in wire cages. Connecticut says indeterminate tomatoes can have one to four stems, and that fewer stems means fewer but larger fruit. Pick a number and prune to it.
When should you top tomato plants?
Late in the season. Iowa State University Extension says topping indeterminate plants is best done about four to six weeks before your average first fall frost date, and that doing it too early can reduce overall plant growth and yields. Skip topping determinate types, which Iowa State says will significantly reduce their yields.