By Richard Jauron–Iowa State University Extension and Outreach
AMES, Iowa – Tomatoes are easy to grow and produce excellent yields. For more information on growing tomatoes, contact Iowa State University Extension and Outreach horticulture specialists at [email protected].
Determinate vs. indeterminate
Determinate and indeterminate refer to the tomato plant’s growth habit.
Determinate tomatoes are small, compact plants that grow to a certain height, then flower and set all their fruit within a short time frame. The harvest period for determinate tomatoes is generally four to six weeks, making them good choices for canning as well as fresh consumption.
Indeterminte tomatoes continue to grow, flower, and set fruit until they are killed by the first fall frost. The fruit on indeterminate cultivars usually mature later than determinate tomatoes, but the harvest period often extends over two to three months. Yields are generally higher than determinate types. Indeterminate tomatoes are tall, sprawling plants that usually perform best when supported by stakes or cages.
Suggested tomato cultivars for Iowa include:
- ‘Better Boy’ (indeterminate; red, round, medium-size fruit).
- ‘Brandywine’ (indeterminate; pinkish red, oblate, large fruit).
- ‘Celebrity’ (determinate; red, oblate, medium to large fruit).
- ‘Chef’s Choice Orange’ (indeterminate; orange, round, large fruit).
- ‘Cherokee Purple’ (indeterminate; rose purple, oblate, large fruit).
- ‘Early Girl’ (determinate; red, oblate, medium-size fruit).
- ‘Jet Star’ (indeterminate; red, oblate, medium to large fruit).
- ‘Juliet’ (indeterminate; red, elongated, small fruit).
- ‘Pony Express’ (determinate; red, blocky pear-shaped, medium-size fruit).
- ‘Red Deuce’ (determinate; red, globe-shaped, large fruit).
- ‘Roma VF’ (determinate; red, pear-shaped, medium-size fruit).
- ‘Supersweet 100’ (indeterminate; red, round, cherry-size fruit).
Tomatoes perform best in deep, loamy, well-drained soils. Tomatoes prefer a slightly acidic soil with a pH of 6.0 to 6.8, but can be successfully grown in slightly alkaline soils. Tomatoes need at least six hours of direct sun per day for best yields.
For individuals without suitable sites, determinate tomato cultivars, such as ‘Celebrity’ and ‘Patio Hybrid,’ can be grown in large 3 to 5-gallon containers.
Plant spacing depends on the growth habit of the cultivar and the training system to be used. Indeterminate cultivars that are staked can be planted 1½ to 2 feet apart within the row. If grown in wire cages, space plants 2-3 feet apart. Tomatoes allowed to sprawl over the ground should be spaced 3-4 feet apart. Rows should be spaced 4-5 feet apart.
Determinate tomatoes can be planted 1½ to 2 feet apart in rows that are 4 feet apart.