How to Prune Tomato Plants for a Bigger Harvest
Last summer, a guy from Arlington Heights stopped me in the garden center looking completely overwhelmed. He had photos on his phone of his tomato plants – and honestly, they looked like a jungle. Branches everywhere. Leaves tangled together. Tiny tomatoes hidden somewhere in the mess.
“I don’t understand,” he said. “I planted four tomato plants and got maybe a dozen tomatoes all season.” I asked him one question: “Did you prune tomato plants?” He looked at me like he’d never heard of the concept.
Why Prune Tomato Plants at All?
Here’s the deal. Tomato plants are energy factories. They take sunlight and turn it into fruit. But if your plant is spending all its energy growing leaves and side branches, guess what it’s NOT doing? Making your tomatoes.
When you prune tomato plants, you’re basically telling the plant: “Hey, focus on fruit, not foliage.” The result? Bigger tomatoes. More of them. Earlier ripening. And way fewer disease problems since air can actually circulate through the plant.
A customer from Schaumburg told me last year that pruning felt “wrong” at first – like she was hurting the plant. But by August, her pruned tomatoes were producing twice as much as her neighbor’s unpruned jungle. Trust the process.
The Pruning Payoff
At Goebbert’s Farm & Garden Center, we talk tomato care with customers from Schaumburg, South Barrington, Hoffman Estates, and Algonquin all summer long.
The single biggest mistake we see? People letting their tomato plants grow wild without pruning. Once you learn to prune, you’ll never go back.
First Things First: Know Your Tomato Type
Before you grab your pruners, you need to know what kind of tomato you’re growing. This matters alot because different tomato types need different pruning approaches.
Indeterminate Tomatoes
These need pruning. Indeterminate varieties keep growing and producing all season until frost kills them. They can reach 6-10 feet tall if you let them. Most heirloom tomatoes and popular varieties like Better Boy, Big Beef, and Cherokee Purple are indeterminate.
Without pruning, indeterminate tomatoes turn into unmanageable monsters. They put tons of energy into leaf growth instead of fruit production. These are the ones you want to prune tomato plants regularly throughout the season.
Determinate Tomatoes
These need minimal pruning. Determinate varieties grow to a set size, produce all their fruit at once, then stop. Roma tomatoes, Celebrity, and most paste tomatoes are determinate. They’re compact and bushy by nature.
Don’t heavily prune determinate tomatoes – you’ll remove potential fruit. Just remove suckers below the first flower cluster and any leaves touching the ground. That’s it. Let them do their thing.
Not sure which type you have? Check the tag that came with your plant or ask us at Goebbert’s. We label everything clearly because it matters for how you’ll care for them all season. If you’re dealing with unpredictable spring weather, knowing your tomato type also helps you decide when to plant and how to protect them.
Step-by-Step: How to Prune Tomato Plants
Alright, let’s get into the actual technique. Grab your pruners (or just use your fingers for small suckers) and let’s go.
Step 1
Wait until plants are 12-18 inches tall. Young plants need their leaves for energy. Don’t start pruning too early.
Step 2
Remove all suckers below the first flower cluster. These lower suckers won’t produce quality fruit anyway. Pinch them off cleanly.
Step 3
Decide how many main stems you want. Most gardeners keep 1-3 main stems. More stems equals more (but smaller) fruit.
Step 4
Check plants weekly. New suckers appear constantly. A quick 5-minute check once a week keeps things under control.
Step 5
Remove lower leaves as plant grows. Leaves touching the soil spread disease. Remove the bottom 12 inches of foliage.
Step 6
Top the plant 4-6 weeks before first frost. Cut the main growing tip so energy goes to ripening existing fruit.
What Are Tomato Suckers?
Suckers are the key to understanding how to prune tomato plants. A sucker is a small stem that grows in the “armpit” between the main stem and a branch. Left alone, each sucker becomes a whole new branch with its own leaves, flowers, and fruit.
Sounds good, right? More branches equals more tomatoes? Nope. Each sucker drains energy from the main plant. Too many suckers means the plant spreads itself thin – lots of small, slow-ripening tomatoes instead of fewer big, juicy ones that ripen on time.
Think of it like this: would you rather have 50 tiny green marbles or 20 fat red tomatoes? The choice is yours, and its made with your pruning shears.
How to Find Suckers
Look at your tomato plant. See the main stem going straight up? Now look at the branches coming off that stem. Right where each branch meets the main stem, there’s a little V-shaped crotch. That’s where suckers grow.
When suckers are small (under 2 inches), they’re easy to spot – little green shoots pointing upward at a 45-degree angle. Bigger suckers look just like regular branches, which is why its important to catch them early. Once a sucker gets bigger than your thumb, removing it creates a wound that can invite disease.
The “Missouri Pruning” Technique
Here’s a trick some gardeners swear by. Instead of removing the entire sucker, you just pinch off the tip, leaving one or two leaves behind. This is called Missouri pruning.
Why bother? Those remaining leaves provide extra shade for developing fruit (preventing sunscald) while still limiting the sucker’s growth. It’s a good middle-ground approach if you’re nervous about removing too much.
When to Prune Tomato Plants
Timing matters. Here’s when to have your pruners ready:
Early morning is best. Plants are hydrated and wounds heal faster. Avoid pruning in the heat of afternoon or when plants are wet from rain (spreads disease).
Start when plants are established. Wait until they’re 12-18 inches tall with their first flower cluster forming. Before that, let them grow.
Prune weekly throughout the season. A few minutes each week beats an hour-long battle with an overgrown jungle. Set a reminder on your phone if you need to. Once you get into the rhythm, it becomes second nature.
Stop pruning 4-6 weeks before frost. In our Zone 5 Illinois climate, that means mid-September. At this point, focus shifts from growth to ripening what’s already there.
Common Pruning Mistakes to Avoid
We see these mistakes all the time at Goebbert’s. Learn from other gardeners’ errors so you don’t repeat them.
Mistake #1: Pruning determinate tomatoes heavily. Remember, determinate varieties have a set number of fruit clusters. Prune too much and you’re literally removing your harvest. Stick to lower sucker removal only.
Mistake #2: Waiting too long between pruning sessions. A sucker can grow 6 inches in a week during peak season. Check weekly or those tiny shoots become major branches.
Mistake #3: Removing too many leaves at once. Leaves power the plant. Never remove more than one-third of the foliage in a single session. Drastic pruning shocks the plant and slows fruit production.
Mistake #4: Using dirty tools. Disease spreads fast through pruning cuts. Wipe your pruners with rubbing alcohol between plants, especially if you notice any sick-looking foliage.
Mistake #5: Pruning when plants are wet. Bacteria and fungi love moisture. Wait until leaves are dry before you start snipping.
Mistake #6: Confusing suckers with main stems. Before you cut, make sure you’re removing an actual sucker and not the main growing tip. If unsure, wait a day and watch where new growth appears.
What to Do With All Those Tomatoes
Here’s the fun part. Once you start pruning properly, you’re gonna have more tomatoes than you know what to do with. Seriously. Pruned plants are efficient plants, and efficient plants produce like crazy.
You’ll be giving bags to neighbors. You’ll be making sauce and freezing it. You’ll be eating BLTs every day for a month. Check out our 5 best fresh tomato recipes for ideas on what to do with your harvest.
A couple from Hoffman Estates told us they canned 40 jars of salsa last summer after they started pruning properly. Forty jars! From six plants! That’s what good pruning technique can do for your garden.
Get Your Tomato Plants at Goebbert’s
We carry dozens of tomato varieties at Goebbert’s Farm & Garden Center in Barrington – both determinate and indeterminate types, all clearly labeled so you know exactly what pruning approach to take. Our staff can walk you through the basics of how to prune tomato plants and answer any questions you have about your specific varieties.
We also stock the tools you need: clean bypass pruners, tomato cages, stakes, and ties. Stop by and let’s get your tomato game to the next level this summer.
And if you’ve never pruned before, don’t be intimidated. Every experienced gardener started as a nervous beginner with a pair of pruners and a questionable-looking sucker. You’ve got this.