All About Pruning Tomatoes (2024)

All About Pruning Tomatoes (1)

We’re all used to pruning plants like trees, shrubs, and flowering perennials, but tomatoes? If you’ve ever grown tomatoes in your vegetable garden, you know how easily they can take over their space with their jumbly growth. And with Square Foot Gardening, if a plant misbehaves and takes over its space, chances are pretty good that it will take over its neighbor’s space, as well. So, let’s learn some basics about pruning tomatoes to keep all the neighbors happy and healthy.

Determinate vs. Indeterminate Tomatoes

Okay, before we talk about the “how,” we need to quickly go over the “what” and the “why.” Determinate tomato plants produce their crop in a shorter period of time and are typically “bush” types that grow to about 3’ tall. So, we’re not talking about determinate tomatoes here — they are already more contained and well-behaved! (But speaking of determinate tomatoes, even though they are shorter with more easily managed growth, proper spacing at 1 bush tomato in a 2’x2’ square is recommended.) The only pruning that needs to be done for determinate varieties of tomatoes is to remove the leaf branches below the first fruit cluster after it appears. This will reduce the risk of soil splashing up onto the plants during rainfall, which can introduce fungal diseases. Determinate tomatoes can easily be supported with cages that are only 4’ tall. This will help keep the foliage and fruit off the soil.

Indeterminate tomatoes, on the other hand, are “vining” types that can grow up to 20’ (or more!) with branches looming out in every direction. They also produce the largest tomatoes, take longer to mature, and often stick around until the first frost. Because of their immense growth, indeterminate tomato plants require some sort of support system like staking or trellises. The usual cages that work for determinate tomato varieties won’t be tall enough for indeterminate varieties.

So, in this blog post, we’re talking about pruning indeterminate tomatoes to keep them in line and playing well with your other SFG plants.

Why we need to prune indeterminate tomatoes

You might wonder, if you’re planting your indeterminate or vining tomatoes on a trellis, why you’d need to prune them anyway. They’re already growing up, right? Let’s take a look at why it’s not only helpful but often necessary:

  • Garden tidiness. SFG recommends planting one indeterminate tomato per square in the grid. We’re assuming you’re attaching your trellis to the north end of your raised bed and that the tomato is planted in those adjacent squares. The side growth, or suckers, on your tomato plant will always want to grow out rather than up, taking over other squares — so pruning them early on keeps squares distinct and the garden tidy. We love a tidy garden, don’t we?
  • Proper air circulation. Plants with growth that is overgrown and crowded often have poor air circulation, which can lead to all manner of problems in the garden like mildew, rust, and fungal diseases.
  • Garden maintenance. If your plants are so overgrown and you can hardly see your grids on top of the soil, it’ll be pretty tough to maintain and water your garden — and let’s not forget that sticking your arms into out-of-control tomato foliage can often irritate sensitive skin! Proper tomato pruning eliminates all of these hassles so working in your SFG is even more pleasant.
  • Plant vigor. When you prune off those side suckers, your tomato plant can grow stronger and healthier. Why? Because those side branches (suckers) will eventually grow so long that they will take energy away from the main vertical branches and overall plant. And while more stems might mean more tomatoes, those additional tomatoes are often smaller and less tasty.

How to prune your indeterminate tomato plants

Now you might ask, “I can’t prune off all the side branches, that would leave only one stem, right?” Right! What we’re talking about here are the suckers, which grow out at an angle at the axils between the leaves and the main stem, and the side branches underneath the first flower cluster. Try to prune frequently enough to keep only a single main stem, or at most two stems. Here’s how to do it:

  1. Plant your tomato plant by the trellis, but do not tie it to the trellis until the first flower appears.
  2. Once the plant has its first flower cluster, prune off any side branches below that cluster.
  3. On side branches that develop above the first cluster of flowers, keep an eye out for suckers and prune them off as well. Suckers grow out at an angle from where the main stem and side branch connect.
  4. Towards the end of the summer, consider topping or pruning the top part of your tomato plant — this can invigorate the plant into producing a late season harvest. It will also allow the plant to put its energy into maturing the existing fruit before the first frost.

Fun Kids Activity: Take a couple of the suckers and side branches you just pruned, and have your kids place one in a large cup of water and the other in a large cup of moistened vermiculite. Keep the vermiculite moist, and once a week, the kids can remove the branches and compare root growth between the two growing mediums. Encourage them to take notes and notice other differences. If this is done when it is still the proper planting time for tomatoes in your area, these suckers can be planted to have even more tomato plants.

All About Pruning Tomatoes (2024)


All About Pruning Tomatoes? ›

To grow the strongest tomato plant possible, prune side stems below the first fruit cluster. As a tomato plant matures, its lower leaves begin to yellow. Pinch or prune yellowed leaves to prevent disease, improve the tomato plant's appearance, and help the plant keep its energy focused on fruit production.

What parts of tomato plants should be pruned? ›

To grow the strongest tomato plant possible, prune side stems below the first fruit cluster. As a tomato plant matures, its lower leaves begin to yellow. Pinch or prune yellowed leaves to prevent disease, improve the tomato plant's appearance, and help the plant keep its energy focused on fruit production.

How to prune tomatoes to get more fruit? ›

In northern regions, many gardeners go further, removing all suckers as they appear. In warmer zones, though, experts often recommend practicing what's known as Missouri pruning, where you pinch off the leaflets on the end of each sucker, leaving only the two base leaflets in place.

When should tomatoes be pruned? ›

When should I prune my tomatoes? Start pruning in late June or early July when the first tomato flowers are open and easy to identify. Continue with a second and third pruning (as needed) every 10 to 14 days following the first pruning.

How do you prune tomato plants for maximum yield? ›

If you are keeping one leader, remove all suckers (new shoots that develop in the leaf axils). If you are keeping two leaders, save the sucker just below the first flower cluster. Remove all other suckers. Remove suckers when they are still small (less than 2 inches).

What tomato plants should not be pruned? ›

Determinate tomatoes will grow to their mature size, then stop. These types of tomatoes do not require pruning to thrive. Once they reach full size, they'll start all their fruit around the same time.

Should I cut the bottom leaves off my tomato plants? ›

Not only does this make them easier to manage, but continual pruning gives you a better yield. I start by stripping the bottom 2′ of foliage from the plants, which allows for good airflow. This is really important for tomatoes because they are susceptible to soil-borne fungal diseases.

What helps tomatoes produce more fruit? ›

Prune lower branches to free up energy for fruit growth, while pinching off tomato blossoms can promote root development. Keep an eye out for any suckers that may appear and be sure to remove them, to reduce extra vegetative growth and redirect nutrients to the fruit.

Which leaves to remove on tomato plants? ›

The advantage in removing the lower leaves is that the plants energies go into producing fruit rather than a lot of foliage. Also the lower leaves tend to get powdery mildew so it is good to remove them to stop disease spreading.

How do you increase tomato yield? ›

  1. SUNLIGHT, SUNLIGHT, SUNLIGHT. Tomato plants need 10+ hours a day of direct sunlight. ...
  2. DON'T OVER WATER. One of the biggest issues people face when gardening is over watering. ...
Aug 5, 2021

How do you prune tomatoes for dummies? ›

To keep tomato plants vigorous, remove extra side branches. When these suckers are 3 to 4 inches long, remove them by pinching them out or by cutting them back to the main stem with scissors.

Can you prune tomatoes too much? ›

You'll end up with fewer tomatoes overall if you prune the suckers. But the ones your plant produces will grow to a larger size if left to reach full maturity. Your plant will only have to focus its energy on one main vine and can send lots of resources to each piece of fruit so they can grow nice and big.

What happens if you don't pinch out tomatoes? ›

Now that you know how to pinch them out and also stop them, you can ensure most of the energy will go towards producing the trusses that in turn produce the fruit. Not doing this will mean you have a fantastically aromatic yet bushy plant that only produces tiny green unripe tomatoes by the end of the season.

How tall should I let my tomato plants grow? ›

When the plant reaches the desired height–usually no taller than its support, 4 or 5 feet is good–consistently pinch out all new growing tips. In a week or so time, the plant will quit trying to put out new growth at the topmost part of the plant and concentrate on new growth and fruit below.

How do you prune tomatoes for the most fruit? ›

Most tomato pruning involves removing suckers -- the shoots that form in the axils where side branches meet the stem. Remove suckers when they're small by pinching them off with your hand or snipping them with pruners. If your goal is to maximize the harvest, prune suckers sparingly.

What happens when you cut off the top of a tomato plant? ›

Topping is a key strategy to getting all of those green tomatoes to ripen faster. Removing the growing tips sends a signal to the tomato plant that it's time to stop putting out new growth and instead, focus on ripening what's left.

How to stop tomato plants from growing too tall? ›

Cutting the tomato plants

The plants grow quite tall in summer and I often notice bunches of green tomatoes that I know won't ripen in time. That's when I cut the top off the tomato plants. This is a great way to keep the plant from growing even larger and instead ripening the fruits.

Should leggy tomato plants be pruned? ›

Prune. If the tomato seedling has grown too tall and spindly, you can prune it back to just above the first set of true leaves. This will encourage the plant to grow new shoots and become bushier.


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