Yard and Garden: Plant Tomatoes in Spring

April 22, 2015, 1:54 pm | Richard Jauron, Greg Wallace

AMES, Iowa - Tomatoes are a popular part of many Iowa gardens, and with spring here, the time to plant them is approaching. But when is too early to plant? Where should they be planted? And what variety is best for a home garden?

Here are some tips from Iowa State University Extension and Outreach horticulturists on the proper way to plant and handle tomatoes in home gardens. 

When can I plant tomatoes in Iowa?

Transplant tomatoes into the garden after the danger of frost is past. In central Iowa, it’s usually safe to plant tomatoes around May 10. Gardeners in southern Iowa can plant one week earlier, while those in northern areas should wait an extra week. The last practical date for planting tomatoes is approximately June 20.


What is a suitable planting site for tomatoes?

Tomatoes perform best in fertile, well-drained soils. Avoid heavy clay soils and poorly drained sites. For best yields, tomatoes need at least six hours of direct sun per day. To discourage Septoria leaf spot, early blight and other foliar diseases, plant tomatoes in a different location in the garden each year.

If possible, rotate crops so that tomatoes and other solanaceous crops (potatoes and peppers) are not grown in the same area for three or four years. Individuals without a suitable garden site can grow tomatoes in large four to five-gallon containers. Place the containers on a sunny patio or deck.

What is meant by the terms determinate and indeterminate?

Determinate and indeterminate refer to the tomato’s growth habit. Determinate tomatoes are small, compact plants. They grow to a certain height, stop, and then flower and set all their fruit within a short period of time. The harvest period for determinate tomatoes is approximately four to six weeks.

Indeterminate tomatoes continue to grow, flower, and set fruit until killed by the first frost in fall.  Accordingly, the harvest from indeterminate cultivars often extends over a two- to three-month period. Yields are generally heavier than determinate types, but are usually later to mature. Indeterminate tomatoes are large, sprawling plants that perform best when grown in wire cages or trained on stakes.

What are some good tomato varieties for the home garden?

Suggested tomato cultivars for Iowa include ‘Better Boy’ (indeterminate; red, round, medium-sized fruit), ‘Big Beef’ (indeterminate; red, oblate, large fruit), ‘Brandywine’ (heirloom; indeterminate; deep pink, oblate, large fruit), ‘Carolina Gold’ (determinate; golden orange, oblate, large fruit), ‘Celebrity’ (determinate; red, oblate, medium to large fruit), ‘Cherokee Purple’ (heirloom; indeterminate; purplish brown, oblate, large fruit), ‘Jet Star’ (indeterminate; red, oblate, medium to large fruit), ‘Mountain Fresh Plus’ (determinate; red, globe-shaped, large fruit), ‘Pony Express’ (determinate; red, elongated, medium-sized fruit), ‘Solid Gold’ (indeterminate; golden yellow, oval, small, grape-type fruit), and ‘Supersweet 100’ (indeterminate; red, round, small, cherry-type fruit).

What is the proper spacing when planting tomatoes in the garden? 

Spacing of tomato plants depends on the growth habit of the cultivar and training system employed. Indeterminate cultivars that are staked can be planted one and a half to two feet apart in the row.  Indeterminate plants grown in wire cages should be spaced two and a half to three feet apart, while a three- to four-foot spacing would be appropriate for indeterminate tomatoes allowed to sprawl over the ground. Determinate tomatoes can be planted two to two and a half feet apart. Rows should be spaced about four feet apart.  

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