Determinate or Indeterminate Tomatoes?

Question: What is the difference between determinate and indeterminate tomatoes? Which kind should I plant? What planting guidelines should I follow?

What great questions! Many people may not understand that the determinate/indeterminate property of tomatoes affects the way plants look, behave and bear fruit.

There are literally hundreds of tomatoes varieties, which differ in color, size, disease resistance and time to maturity. Before you select specific tomatoes to grow, you will want to decide which of the two main types of tomatoes (determinate and indeterminate) to plant. You may even want to plant both types!

The distinguishing characteristic between determinate and indeterminate varieties is their growth habit.

Determinate tomato plants are also known as “bush” tomatoes because they grow in a bush-like manner. At first, the plant grows vertically, but then vertical growth stops. The remainder of the growth will be side shoots, and the maximum height is typically 4 feet or less. Most of the early-ripening tomato varieties are determinate and are generally less flavorful than indeterminate types. Crop bearing is usually over a 4- to 5-week period.

In contrast, indeterminate tomatoes are more vine-like and can reach heights of 6 feet or more. They are often more flavorful when compared to determinates and will continue to flower and produce fruit during the growing season and up to the first frost.

For a good overview of determinate versus indeterminate, read this article from the UCCE Master Gardeners of San Bernardino County.

Which should I plant?
The obvious advantage of the indeterminate plants is tomato production over a longer season. In contrast, many determinate varieties start producing earlier in the season. If you like to can, freeze, or dehydrate your produce, determinate tomatoes will yield a large quantity of fruit in a shorter time, which can be convenient.

Examples of determinate tomatoes: Rutgers, Roma, and Celebrity.

Examples of indeterminate tomatoes: Beefsteak, Goldie, most Cherry-types, and heirloom tomatoes.

Which to plant?
If you are short on space, determinate tomatoes are good for container gardening. However, if you have the room, you may want to select some of each! There are other considerations as you select specific varieties such as flavor profile, size, color, disease resistance; even whether you prefer to eat fresh tomatoes or cook with them. For an extensive database of tomato varieties including descriptions and images, visit the Rutgers University listing.

What are some of the planting guidelines?
Most of the cultural practices for planting tomatoes are the same for determinate and indeterminate varieties. Transplant after the danger of frost is past and the soil has warmed, which is approximately at the beginning of May in central Virginia. For example, the average last frost date for USDA hardiness zone 7a is April 15 to 25, but frosts can happen even later. Space plants 36 inches by 36 inches, if staked or caged.

This may sound a little strange, but when transplanting tomatoes, create a shallow trough and plant each tomato with only one or two sets of leaves above ground. This encourages strong root growth. If planted too deeply, the soil may be too cool. The average soil temperature should be 60-65 degrees F for transplanting into the garden. Tomatoes are heavy feeders, so use a starter fertilizer solution for transplants and then side-dress with fertilizer (adding fertilizer around the stem of the plant) one or two weeks after the first cluster of tomatoes begin to develop.

Determinate plants do well in tomato cages and need minimal staking. They also do not require heavy pruning or sucker removal for a good crop yield. In fact, pruning can significantly reduce the yield. In contrast, indeterminate tomatoes must either be caged or staked and do better with the removal of suckers (after two leaves on the sucker appear). For more information on pruning and staking tomatoes, read the publication Staking and Pruning Tomatoes in the Home Garden from the University of Georgia Extension.

Both types require regular watering. Water at the base of plant, rather than getting water on the leaves. If possible, use a soaker hose to water slowly, deeply and infrequently. This will encourage deep roots and lower the likelihood of disease.

Good luck, and get ready to harvest those wonderful summer tomatoes! Check back later for a future posting on dwarf tomatoes.

References

“Staking and Pruning Tomatoes in the Home Garden,” University of Georgia Extension, Circular 1150, 2019.

“Tomato Varieties,” Rutgers, New Jersey Agricultural Experiment Station.

“Tomatoes,” Diane Relf et al., Virginia Cooperative Extension, Virginia Tech, Publication 426-418, 2016.

“Virginia‚Äôs Home Garden Vegetable Planting Guide: Recommended Planting Dates and Amounts to Plant,” Alex Hessler, Virginia Cooperative Extension, Virginia Tech, Publication 426-331.

“What’s the Difference Between Determinate and Indeterminate Tomatoes?” Shelley Stone-Schmidt, University of California, Agriculture and Natural Resources, UCCE San Bernardino County Master Gardeners, 2015.

Epic Tomatoes: How to Select & Grow the Best Varieties of All Time, Craig LeHoullier, Storey Publishing, 2015.

The Vegetable Gardener’s Bible, Edward C. Smith, Storey Publishing, 2009.

Vegetable Gardening in the Southeast, Ira Wallace, Timber Press, 2013.