When to plant carrots 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). Carrot needs 60–80 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 carrots in Montana: the short answer
For a spring planting, sow Apr 19 – May 8. Seeds germinate in soil from 40 to 85°F.
Succession sow again in Montana: May 12 · May 30 · Jun 17
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 carrots in Montana, step by step
- Prepare the bed. They need 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 12 inches deep, with a pH between 5.5 and 7.0. Dig in compost before planting.
- Sow outdoors (Apr 19 – May 8). Space plants about 3 inches apart in rows 12 inches apart, sowing seed ¼ inch deep. It handles frost well, so it can go out before the last frost date. 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: carrot rust fly, wireworm, root-knot nematode, aphids. Diseases and disorders: alternaria leaf blight, cavity spot, aster yellows.
- Harvest (from about Jun 23 – Jul 13). Carrot takes 60-80 days to reach harvest. Never transplant. Keep the surface constantly moist for the slow 2-3 week germination - a board or burlap over the row helps. Needs loose, stone-free soil or roots fork.
Figures come from our crop data; dates use Montana’s average frost dates. More in the full carrot growing guide.
Carrot 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 carrot dates shift with them.
When to plant carrots in nearby states
Questions gardeners in Montana ask
When is the best time to plant carrots in Montana?
Sow carrots in Montana between April 19 and May 8. 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.
Can I plant carrots in the fall in Montana?
Yes. For a fall crop, sow between June 20 and July 7, so the crop matures in cool weather before Montana's first frost around September 15.
When will carrots planted in Montana be ready to harvest?
Planted on time, carrots are usually ready from about June 23 to July 13, 60-80 days after sowing.
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.