When to plant lettuce in South Dakota
South Dakota’s average last spring frost is May 10, and the first fall frost typically arrives around September 25 — about 138 frost-free days (USDA zones 3b, 4a, 4b, 5a). Lettuce needs 30–60 days to mature, which fits comfortably within South Dakota's growing season.
When to plant lettuce in South Dakota: the short answer
For a spring planting, plant out Apr 19 – May 6, with seeds started indoors Apr 5 – Apr 19. Seeds germinate in soil from 35 to 80°F.
Succession sow again in South Dakota: May 8 · May 20 · Jun 1 · Jun 13
Spring succession stops before summer heat makes it bolt. Start sowing again in late summer for a fall crop (see the fall window above).
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow lettuce in South Dakota, step by step
- Start seeds indoors (Apr 5 – Apr 19). Sow seeds ⅛ inch deep in seed-starting mix under bright light. They take 2-10 days to sprout, fastest in soil around 65°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. It needs six or more hours of sun for the best growth, though four to six hours in partial shade is enough and loose soil at least 8 inches deep, with a pH between 6.0 and 7.0. Dig in compost before planting.
- Plant out (Apr 19 – May 6). Space plants about 10 inches apart in rows 14 inches apart. It tolerates a light frost but not a hard freeze. As a cool-season crop it does best before summer heat arrives in South Dakota.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: aphids, slugs, snails, cutworm. Diseases and disorders: downy mildew, bottom rot, tipburn (calcium disorder).
- Harvest (from about May 26 – Jun 25). Lettuce takes 30-60 days to reach harvest. Seed needs light - barely cover it. Will not germinate above ~80 F soil. Loose-leaf types give the fastest, most forgiving cut-and-come-again harvest.
Figures come from our crop data; dates use South Dakota’s average frost dates. More in the full lettuce growing guide.
Lettuce planting dates by USDA zone in South Dakota
South Dakota spans USDA zones 3b, 4a, 4b, 5a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the lettuce dates shift with them.
When to plant lettuce in nearby states
| State | Last frost | Plant out |
|---|---|---|
| South Dakota (this page) | May 10 | Apr 19 – May 6 |
| North Dakota | May 15 | Apr 24 – May 11 |
| Nebraska | April 30 | Apr 9 – Apr 26 |
| Kansas | April 15 | Mar 25 – Apr 11 |
| Oklahoma | April 1 | Mar 11 – Mar 28 |
Questions gardeners in South Dakota ask
When is the best time to plant lettuce in South Dakota?
Plant lettuce transplants outdoors in South Dakota between April 19 and May 6. That timing is set by South Dakota's average last spring frost of May 10.
When should I start lettuce seeds indoors in South Dakota?
Start seeds indoors between April 5 and April 19, about 4 weeks before the last frost, so the seedlings are ready to plant out from April 19.
Can I plant lettuce in the fall in South Dakota?
Yes. For a fall crop, sow between July 21 and August 7, so the crop matures in cool weather before South Dakota's first frost around September 25.
When will lettuce planted in South Dakota be ready to harvest?
Planted on time, lettuce is usually ready from about May 26 to June 25, 30-60 days after planting.
When is the last frost in South Dakota?
On average around May 10, with the first fall frost around September 25 - about 138 frost-free days. Your town may differ by two weeks or more.