When to plant carrots in Idaho
Idaho’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, 4b, 5b, 6a, 6b, 7a). Carrot needs 60–80 days to mature, which fits comfortably within Idaho's growing season.
Idaho 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 Idaho: the short answer
For a spring planting, sow Apr 14 – May 3. Seeds germinate in soil from 40 to 85°F.
Succession sow again in Idaho: May 7 · May 25 · Jun 12
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 Idaho, 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 14 – May 3). 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 Idaho.
- 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 18 – Jul 8). 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 Idaho’s average frost dates. More in the full carrot growing guide.
Carrot planting dates by USDA zone in Idaho
Idaho spans USDA zones 3b, 4b, 5b, 6a, 6b, 7a. 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 Idaho ask
When is the best time to plant carrots in Idaho?
Sow carrots in Idaho between April 14 and May 3. That timing is set by Idaho's average last spring frost of May 10; Idaho spans several climates, so cooler and higher parts of the state run later.
Can I plant carrots in the fall in Idaho?
Yes. For a fall crop, sow between June 30 and July 17, so the crop matures in cool weather before Idaho's first frost around September 25.
When will carrots planted in Idaho be ready to harvest?
Planted on time, carrots are usually ready from about June 18 to July 8, 60-80 days after sowing.
When is the last frost in Idaho?
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.