Determinate Vs. Indeterminate Tomatoes: What’s The Difference?
The terms determinate and indeterminate refer to how tomato plants grow, but they also impact fruit sets, trellising methods, and more. Join vegetable farmer Briana Yablonski as she explains the differences between determinate and indeterminate tomatoes.
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As you search for the perfect tomato variety, you’ve probably come across the terms determinate and indeterminate. But do you know the differences between these two tomato growth habits? And do you know which one is best for your garden?
When it comes time to choose tomato plants for your garden, you have many options. From big beefsteak tomatoes perfect for BLTs to candy-sweet cherry tomatoes, there’s a tomato for everyone. But you should pay attention to more than just the fruit size and color.
I’ll cover the differences between determinate and indeterminate tomatoes so you can choose the best option.
The Short Answer
The terms indeterminate and determinate relate to a tomato plant’s growth habit. Indeterminate tomatoes continue growing until they die, producing new flowers and fruits along the way. Determinate tomatoes grow until they reach their maximum height and typically produce all their fruit within a few weeks.
The Long Answer
The big difference between indeterminate and determinate tomatoes is how they grow. This difference impacts harvest, staking, pruning, and more! Learning about the differences between these two groups will help you choose one that meets your goals and fits in your garden.
Plant Growth
As I mentioned above, determinate tomatoes grow until they reach a certain size, and indeterminate tomatoes continue to grow until they are killed by frost, disease, or another factor.
I’ve grown multiple varieties of both types, and believe me when I say there’s a big difference in size. Determinate tomatoes typically max out at about three to four feet tall, so you can easily contain them using wire tomato cages or trellis them with wooden stakes and twine. Indeterminate tomatoes can easily grow over ten feet tall, so you need a more extensive trellising system to keep them contained.
I regularly grow indeterminate tomatoes in high tunnels and trellis them using a lower and lean method. The tomato vines reach the top of the trellis wire, eight to ten feet tall, by mid-summer. At this point, it’s time to lean the tomato plants down the length of the tunnel so they can continue growing. I’ve seen indeterminate tomatoes grow over 30 feet long by fall!
This long length means indeterminate tomatoes aren’t the best for containers or small gardens. However, indeterminates are rewarding to grow if you don’t mind extra work trellising your plants.
Fruit Set
The different growth habits also create differences in how these plants produce flowers and fruit. Indeterminate tomatoes produce new flowers and fruit as they grow, leading to a longer harvest window. Determinate tomatoes set all their fruit in a few weeks.
Indeterminates are a great option for enjoying tomatoes all summer. Each plant will provide a weekly handful of cherry tomatoes or a few slicing tomatoes for sandwiches. However, don’t expect a single, record-breaking harvest.
Since determinates produce all their fruit in a few weeks, they’re a great choice if you want to preserve your harvest. Each healthy plant produces around ten pounds of fruit in a few weeks, which allows you to make salsa for canning or tomato sauce for freezing.
Trellising
As I mentioned above, determinate and indeterminate tomatoes require different types of trellising. Determinate tomatoes are easier to trellis, and some don’t require a trellis at all. Indeterminate tomatoes become unruly and messy if you don’t trellis them, and wrangling them into a neat form requires a bit more work.
Since determinate tomatoes remain under four feet tall, you can easily contain and support them with a wire tomato cage. Another option is to place three or four wooden stakes about eight inches away from the base of your plant. Arrange three stakes in a triangle and four stakes in a square. As the plant grows, wrap twine around the stakes to box in the growth and provide support.
Although you can use tomato cages to support indeterminate tomatoes, the plants will eventually outgrow the cage and cascade over the top. Better trellis options include a cattle panel or the stake and weave method. Using a cattle panel, you can attach the vine to the panel with twine or plastic trellising clips.
You can use the stake and weave method to trellis two plants in a garden or hundreds of plants in a field. I’ve used it on various farms and in community garden plots. However, it’s best for tomatoes planted in a row.
- Insert metal t-posts or wooden stakes on each side of your tomato plant, about six inches away from the stem. The posts should be at least six feet tall, but eight feet is preferable. If you are growing a row of plants, place a stake every three plants.
- Use a mallet or post-pounder to drive the stakes six to eight inches into the ground.
- When the plants are a foot tall, it’s time to trellis. Tie a piece of tomato twine on one stake, run it along the side of the tomato plants to the other stake, pull taught, and tie. The twine should be about eight inches above the ground. Complete this step on the other side of the plant. When you’re finished, the tomato plant should sit between two pieces of twine.
- When the plants have grown about a foot above the first line of twine, add another piece of twine eight to ten inches above the original.
- Repeat this process as your plant grows until the twine reaches the top of the stakes. The vines will trail over the top of the twine, but that’s okay.
Pruning
If you don’t want to prune your tomato plants, that’s fine! Both determinate and indeterminate tomato plants will grow and produce fruit without any. However, pruning indeterminate plants helps keep them tidy, improves airflow, and makes harvesting easier.
The amount you prune depends on your trellising method and personal preferences. Pruning often involves using shears to remove suckers, which are the shoots that appear at the elbows that occur between the main stem and leaves. Removing these suckers limits the size of the plant, which means that it also limits potential fruit production. However, it also allows plants to put their energy into the remaining flowers and fruits, which often leads to larger fruit clusters and tomatoes.
Some people will top their tomato plants when they hit the maximum height they wish them to reach. This process is simple: cut off any excess growth above your determined height. An indeterminate plant will still be able to produce on the lower portion of the plant, and it may start trying to produce a new “leader” or main stalk from one of the lower branches, but this won’t hurt it.
Even if you don’t want to remove suckers from your indeterminate tomato plants, I recommend that you prune off lower leaves. Removing leaves within a foot of the ground discourages the development of tomato diseases like early blight and septoria leaf spot.
When it comes to determinate tomatoes, you don’t have to prune. They will remain manageable without pruning, and removing suckers leads to smaller harvests. However, you can still remove any leaves that touch the soil.
With determinates, it’s best not to top them. They hit a maximum height and stop growing vertically. Most of their additional growth is outwards at that point, but they’re mostly set on size and general form.
Varieties
All types of tomatoes can be determinate or indeterminate. You can find determinate or indeterminate slicers, beefsteak, plum, and cherry tomatoes. So don’t assume that all Roma-type tomatoes are determinate or all heirloom beefsteaks are indeterminate.
Some popular indeterminate varieties include ‘Green Zebra, ‘Sun Gold,’ and ‘Cherokee Purple.’
Determinate varieties include ‘Italian Roma’ and ‘Mountain Merit.’
Final Thoughts
Both determinate and indeterminate tomatoes have a place in the garden, but their differences mean you may enjoy one type over the other. A determinate variety is best if you have a small garden or want to preserve your harvest. And if you don’t mind trellising or want a continual supply of tomatoes all season long, try an indeterminate variety.