When to Plant Tomatoes in Iowa?

Written by

William Golder


Dorian Goodwin

when to plant tomatoes in iowa

Iowa has about 160 frost-free days as its growing season, not very long compared to some other locations like Florida and California.

Within the state, it’s essential to plant tomatoes at the right time, since these fruits can become discolored, wilted, and die under frost exposure. Plus, they take quite long to mature (around 60 to 100 days under warm weather).

If you’re wondering when to plant tomatoes in Iowa, the recommendations are:

  • May 10 in central Iowa
  • May 3 in southern Iowa
  • May 17 in northern Iowa

Discover more tips on growing this crop below.

Best Time to Plant Tomatoes in Iowa

  • When is it safe to plant tomatoes outside? After the final frost is the answer.


Considering that Iowa has its last bout of freezing temperatures around late April to early May, May is the best month for growing tomatoes outdoors.

  • As for when to plant tomatoes inside, you can start seeds five to six weeks before the final frost—or in March—then harden the seedlings off for one week before moving them outside when the weather turns warm.


This measure will help tomatoes adapt to outdoor environments better and minimize transplant shock.

To make determining your tomato planting season easier, here are the last and first frost dates for some locations in Iowa.

Note that tomatoes should mature before the first frost, or have 60 to 100 days to grow before winter arrives. In Iowa, the final planting time is typically June 20, given that the first frost largely comes in October.

Location Average last frost Average first frost
Adair April 25 October 7
Boone April 26 October 6
Clarke April 23 October 10
Dallas April 25 October 6
Des Moines April 15 October 19
Fayette May 1 October 2
Jefferson April 17 October 13

Planting Time Based on Hardiness Zones

Source: ufseeds.com
Hardiness zone Average last frost Plant tomatoes indoors Plant tomatoes outside
Zone 4 May 12 March 31 May 13
Zone 5 April 30 March 19 May 1
Zone 6 April 21 March 10 April 22

Tips for Successful Tomato Planting in Iowa

1. Tomato varieties for Iowa


The best tomatoes to grow in Iowa are:

  1. Better Boy, Brandywine, Cherokee Purple, Jet Star, Supersweet 100, and Juliet for indeterminate tomatoes
  2. Celebrity, Early Girl, Pony Express, Roma VF, and Red Deuce for determinate varieties

While selecting between indeterminate and determinate tomatoes, consider whether you want higher yields and how much space you have.

Indeterminate varieties fruit more during the growing season, but they require more space than determinate types.

These cultivars also require staking or caging, so they are not as suitable for containers as determinate tomatoes.

2. Conditions for growing tomatoes


To grow healthy tomatoes, use loamy, well-drained soil with a pH of 6 to 6.8. Container plants should be put in potting soil and receptacles six inches deep.

Give tomatoes eight hours of direct sun per day to ensure flowers can form, and one to two inches of water weekly so that roots can expand. If using containers, irrigate whenever the top inch of the soil is dry.

It’s also important to submerge the root ball of tomato transplants but not the foliage. The leaves should ideally be 12 inches above the ground to prevent early blight and septoria, and you can pinch them off as tomatoes develop.

As for seeds, plant them ½-inch deep in both containers and garden beds. The lowest temperature for germinating tomatoes is 55℉, with 70 to 80 degrees being optimal.


Now that you know when to plant tomatoes in Iowa, you can make plans for growing them next spring.

Remember to give tomatoes proper spacing as well, which is two feet apart for both smaller determinate varieties and bigger indeterminate varieties with support.

Keep plant rows four feet apart, and follow our care tips above, and you should have yummy, healthy tomatoes to harvest come fall.

Read more: Best time to plant grass seed in Iowa

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