Indeterminate tomatoes are like that friend who runs marathons. They just keep going. Once they finish one marathon, they’re already training for the other.
From the time you pick that first tomato right up until the first frost in fall knocks them out, they just don’t quit—indeterminate tomatoes, not your running friend.
But while they are easy to grow, indeterminate tomatoes are not a “set it and forget it” garden inhabitant. If you turn your back on them, they will take over your garden. If they don’t get the nutrients they need when they need them, you’ll end up with a disappointing yield.
So, while indeterminate tomatoes aren’t particularly fussy, here are five things you should never do when growing them.
1. Don’t Skip Pruning
Saying indeterminate tomatoes are vigorous growers is like saying Tiger Woods likes to play golf – an understatement. Given half a chance, they will completely take over your garden and then start eyeballing your lawn.
Without regular, rigorous pruning, you may need a machete to bring them under control.
By pruning them often, you’ll encourage better airflow, which helps to prevent disease. You’ll also get more sun to the interior of the plant, which will improve flower set and ripening (with more heat, not necessarily more sun).
Suckers (the little shoots that appear in the joint between the main stem and a leaf) should be removed regularly so the plant puts more energy into fruit production. But you don’t want to remove all suckers, as they will produce fruit as well. Just remove enough of them to keep the plant’s zealous growth in check.
2. Don’t Use Small or Weak Supports
If you’ve ever grown indeterminate tomatoes before, you know how quickly they go from minuscule to massive. Not to mention, they get heavy. Even the best tomato cages are no match for a plant that can easily grow over 6 to 10 feet tall. Once the plant gets a little top-heavy, it will easily collapse under its own weight, topping over and yanking the cage out of the ground for good measure. (Ask me how I know.)
You want strong, beefy supports here. Use systems such as T-posts with twine, the Florida weave or trellises. Set them up early, ideally when you plant your tomatoes, so the plants grow into the structure instead of needing to be forcefully tucked in later, which can lead to snapped stems. (Ask me…you get the idea.)
3. Don’t Plant Them Too Close Together
These tomatoes have got plenty of room, right?
Wrong!
Here they are a few weeks later.
Indeterminate tomatoes need room to breathe. Crowding them can reduce airflow, encourage fungal issues like early blight, which can put a swift end to your tomato season, and make it difficult to reach the interior of the plant for pruning or harvesting. These aren’t compact, bushy plants like determinates—they sprawl and climb and need both vertical and horizontal space.
Allow at least 24 to 36 inches of space between plants, depending on your chosen support method. However, if you’re string-training them and pruning them to a single stem, you can get away with much less. But if you’re letting them branch a bit, err on the generous side.
4. Don’t Neglect Ongoing Feeding
I always associate indeterminate tomatoes with Audrey from Little Shop of Horrors, “Feed me, Seymour!”
Whereas determinate tomatoes get most of their nutrients early in the season before setting all their fruit in a short time window, indeterminates are nutrient hogs from the word go. If you don’t feed them regularly after fruiting begins, your plants will slow down, yellow out, or produce smaller, flavorless fruit.
Use a balanced fertilizer early in the season, and fertilize more often once the tomato begins to set flowers and fruit. (We all know I’m a fan of Espoma’s Organic Garden-tone.) Compost teas, fish emulsion, and tomato-specific fertilizers can all help. Feed every 2–3 weeks during heavy production.
5. Don’t Leave Ripe Tomatoes Hanging Too Long
With determinate tomatoes, you get a big harvest all at once and can process the fruit in bulk. With indeterminate varieties, harvest is ongoing. That means you need to stay on top of it. Leaving ripe tomatoes on the vine for too long not only attracts pests and diseases but also signals the plant to slow down or stop producing new fruit.
Here’s a great guide on the proper time to pick tomatoes.
The more often you harvest, the more flowers (and fruit) the plant will produce. Picking regularly keeps your plant productive and keeps you (and your neighbors if you share) stocked with fresh tomatoes.
If you want to grow indeterminate varieties for canning, I highly recommend string-training them, which allows for more plants in a smaller area, resulting in a bigger and more consistent harvest throughout the season.
Indeterminate vs. Determinate: Here’s how they stack up:
Indeterminate tomatoes, sometimes called vining or cordon tomatoes, don’t stop growing until frost kills them. They’ll keep flowering and producing fruit all summer. This contrasts with determinate (or bush) tomatoes, which grow to a certain size and ripen all their fruit in a concentrated burst.
Because of their growth habit, indeterminate tomatoes need regular maintenance—pruning, staking, feeding—and they tend to take up more space in the garden. But in return, you get fresh tomatoes over a much longer period of time.
Growth Habit: Indeterminates grow tall and vine-like. Determinates grow compact and bushy.
Harvest Period: Indeterminates produce steadily over several months. Determinates yield all at once.
Maintenance: Indeterminates need pruning and support. Determinates can get by with less care.
Best Use: Indeterminates are perfect for fresh eating all season. Determinates are great for preserving and sauce-making.
Why Grow Indeterminate Tomatoes?
If you’ve got the time and space, indeterminates are generally the most popular. Here’s why so many gardeners prefer them:
Ongoing Harvest: You’ll be picking ripe tomatoes weekly—or even daily—from mid-summer to frost.
Better Flavor: Many heirloom varieties are indeterminate, and they’re prized for their complex, nuanced taste and gorgeous colors, and we all love our heirloom tomatoes.
More Total Fruit: While determinates seem like they may produce more because it all comes in one big flush, indeterminates often out-produce them overall because of their extended harvest season.
Great for Fresh Eating: Cherry, grape, slicing, and salad tomatoes are often indeterminate, making them perfect for snacking every day.
Popular Indeterminate Varieties
Here are some standouts among indeterminate tomatoes:
- Brandywine: Huge, meaty heirlooms with pinkish skin and deep, old-fashioned tomato flavor.
- Cherokee Purple: Dark and smoky, with a rich taste and a cult following.
- Sungold: Cherry tomatoes with intense sweetness and prolific yields.
- Black Krim: A deep reddish-purple beefsteak with a rich, slightly umami flavor.
- Green Zebra: Striped and tangy, perfect for fresh salads and fancy plating.
Whether you’re after color, flavor, or sheer productivity, there’s an indeterminate tomato variety that fits the bill.
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