What Are Determinate and Indeterminate Tomatoes?

Indeterminate tomato varieties are vining plants that continue to extend in length throughout the growing season, while determinate tomatoes hit their mature height and set all their fruit at once. These terms refer to the growth habit of the tomato plants, which can be called bush (determinate) or vining (indeterminate). 

All tomato plants are vines that would sprawl along the ground without support to grow upward, but indeterminate tomatoes grow much longer than determinate varieties. If left to their natural tendencies, tomato vines can become a damp, tangled mess on the soil, where they attract diseases and pests. For this reason, most gardeners grow tomatoes using stakes, cages, or trellises.

Indeterminate Tomatoes

Indeterminate tomatoes grow, flower, and produce fruit throughout the growing season until the first fall frost kills the plant. These plants can reach heights of up to 12 feet, although 6 feet is typical.

Because of their size, they also require very sturdy staking or caging over the course of the season. The growth pattern on some indeterminate varieties is so robust that ordinary tomato cages are often inadequate. You may need to stake these large plants with heavy metal rebar stakes or another sturdy support structure.

Providing Support

Indeterminate tomato varieties need large, sturdy stakes or caging for support because of how long they grow. The plants can reach 6 to 12 feet and become very heavy.

You can buy various kinds of staking structures for tomatoes, or make your own. If using metal tomato cages, be aware the the smaller ones won't be sufficient to support these large plants, Get the largest ones you can find (at least 4 feet tall) and reinforce with wood or bamboo stakes.

Wooden or metal stakes can provide good support for tomato plants, but you may want to add some additional support with twine, or twist ties.

Pruning

Pinch back some of the suckers on indeterminate tomatoes to prevent unmanageable growth. Never pinch out a sucker directly below a blossom, as this causes uneven growth in the plant and will reduce your harvest.

Your tomato plants may get a lot of leaves and this will sometimes prevent the fruit from getting ample sunlight. To get them to ripen faster and more evenly, trim some of these leaves. This also directs more of the plant's energy towards the ripening fruit.

How to Harvest Indeterminate Tomatoes

Indeterminate tomatoes will give you a slow and steady supply of tomatoes, rather than one large harvest. However, they tend to start ripening a little later in the season than determinate varieties do because they first spend a good amount of time growing tall.

Your plants may keep producing fruit late into the season, so be sure to keep an eye on the nightly temperatures. If there's any danger of frost, pick your tomatoes, even the green ones, You can always set them in a sunny windowsill or inside brown paper bags to ripen off the vine.

Determinate Tomatoes

Determinate tomatoes grow to a predetermined height (approximately 4 feet tall). The plant stops growing when fruit sets on the top bud, and all fruit ripens at or near the same time (usually over a two-week period), and then the plant stops producing fruit and dies. Most sauce tomato varieties are determinate so that the entire crop ripens at once for making sauce, canning, and jarring in large batches. The restricted growth habit makes indeterminate tomatoes more suitable for growing in containers than indeterminate tomatoes and consume much less garden space.

Providing Support

Staking is required but not nearly as much as the heavy-duty staking required by indeterminate tomato varieties. The plants will be supporting a heavy load once all of the fruits set and begin to plump up and ripen. This can put considerable weight on the branches, so staking will help the plant.

Pruning

Pruning and removing suckers from determinate tomatoes is generally not needed because they stop growing on their own.

How to Harvest Determinate Tomatoes

Determinate tomato plants ripen all their fruit in a short period (usually about two weeks). Once this first flush of fruit has ripened, the plant will begin to diminish in vigor and will set little to no new fruit.

Considerations

Both determinate and indeterminate tomato varieties have their pluses and minuses. It really depends on how you plan to use the tomatoes and the length of your growing season. If you want a thick tomato for making sauces, you are better off with a paste tomato, which tends to be determinate with fewer seeds and more meat. If you typically eat your tomatoes fresh and want a season-long supply, go for an indeterminate variety.

Moreover, if you live where the growing season is only a couple of months long, determinate tomatoes might be the better growing choice for you. However, there are short-season indeterminate varieties, such as the early maturing tomatoes, that would probably ripen for you. Experiment to see which varieties grow best in your area, as well as which you enjoy eating the most.

Recommended Determinate and Indeterminate Tomato Varieties

The majority of tomato varieties are indeterminate, including most heirlooms and cherry types. Even many dwarf tomato varieties are indeterminate. Some of the most popular tomatoes to grow, including 'Beefsteak', 'Big Boy', 'Brandywine', 'Sungold', and 'Sweet Million', are indeterminate varieties.

Early producing varieties, such as 'Early Girl', are also indeterminate. However, because they tend to mature earlier and die back before the end of the growing season, they are sometimes labeled semi-determinate.

Here are some suggestions for recent tomato varieties with good reviews from horticulturalists and garden authorities:

Determinate Varieties

• Celebrity: Determinate hybrid globe tomato. Produces fruit about 8 to 10 ounces in size about 70 days from planting.
• San Marzano Nano: Unlike other San Marzano tomatoes, this one is determinate and the plant stays at a manageable size. This Roma-style heirloom plum tomato is juicy, flavorful and a highly-desirable cooking tomato. The thin skins need not be removed before making sauce.
• Amish Paste: This medium-sized pear tomato is a sweet-tasting heirloom that grows to between 8-12 ounces. It's excellent for cooking and canning, and also good for slicing into salads. As with other heirloom tomatoes, the seeds may be gathered after harvest for replanting the folloowing season.
• Marglobe: Determinate heirloom with a somewhat spreading growth habit. Ripens at 75 days, disease resistant with very firm flesh that resists bruising and cracking.
• Rutgers: Determinate variety that produces a large early crop of fruit followed by several more during the season. Strong, disease-resistant plants, flavorful fruits that stand up to handling.

Indeterminate Varieties

• Better Boy: Indeterminate hybrid beefsteak tomato. Produces fruit 10 to 16 ounces in size about 75 days from planting.
• Big Beef: Indeterminate hybrid beefsteak tomato. Produces fruit 10 to 12 ounces in size about 73 days from planting. Was a 1994 All-America Selections Winner.
• Big Boy: Indeterminate hybrid tomato. Produces fruit 10 to 16 ounces in size about 78 days after planting.
• Early Girl: Indeterminate hybrid globe tomato. Produces fruit about 8 ounces in size about 50 to 52 days after planting.
• Juliet: Indeterminate hybrid elongated cherry tomato. Produces 1-ounce fruit about 60 days after planting. Was a 1999 All-America Selections Winner.
• Sun Sugar: Indeterminate hybrid cherry tomato with orange fruit. Produces 1-ounce fruit about 62 days after planting.