When to plant lettuce in Montana
Montana’s average last spring frost is May 15, and the first fall frost typically arrives around September 15 — about 123 frost-free days (USDA zones 3a, 3b, 4a, 4b, 5a, 5b, 6a). Lettuce needs 30–60 days to mature, which fits comfortably within Montana's growing season.
Montana covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant lettuce in Montana: the short answer
For a spring planting, plant out Apr 24 – May 11, with seeds started indoors Apr 10 – Apr 24. Seeds germinate in soil from 35 to 80°F.
Succession sow again in Montana: May 13 · May 25 · Jun 6 · Jun 18
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 Montana, step by step
- Start seeds indoors (Apr 10 – Apr 24). 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 24 – May 11). 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 Montana.
- 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 31 – Jun 30). 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 Montana’s average frost dates. More in the full lettuce growing guide.
Lettuce planting dates by USDA zone in Montana
Montana spans USDA zones 3a, 3b, 4a, 4b, 5a, 5b, 6a. 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
Questions gardeners in Montana ask
When is the best time to plant lettuce in Montana?
Plant lettuce transplants outdoors in Montana between April 24 and May 11. That timing is set by Montana's average last spring frost of May 15; Montana spans several climates, so cooler and higher parts of the state run later.
When should I start lettuce seeds indoors in Montana?
Start seeds indoors between April 10 and April 24, about 4 weeks before the last frost, so the seedlings are ready to plant out from April 24.
Can I plant lettuce in the fall in Montana?
Yes. For a fall crop, sow between July 11 and July 28, so the crop matures in cool weather before Montana's first frost around September 15.
When will lettuce planted in Montana be ready to harvest?
Planted on time, lettuce is usually ready from about May 31 to June 30, 30-60 days after planting.
When is the last frost in Montana?
On average around May 15, with the first fall frost around September 15 - about 123 frost-free days. Your town may differ by two weeks or more.