When to plant winter squash in Minnesota
Minnesota’s average last spring frost is May 6, and the first fall frost typically arrives around September 28 — about 145 frost-free days (USDA zones 3a, 3b, 4a, 4b, 5a). Winter Squash needs 80–110 days to mature, which fits comfortably within Minnesota's growing season.
When to plant winter squash in Minnesota: the short answer
For a spring planting, plant out May 6 – May 23, with seeds started indoors Apr 8 – Apr 22. Wait until the soil is at least 60°F and frost is over.
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 winter squash in Minnesota, step by step
- Start seeds indoors (Apr 8 – Apr 22). Sow seeds 1 inch deep in seed-starting mix under bright light. They take 5-10 days to sprout, fastest in soil around 85°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 18 inches deep, with a pH between 5.5 and 7.0. Dig in compost before planting.
- Plant out (May 6 – May 23). Space plants about 42 inches apart in rows 72 inches apart. It is killed by frost, so nothing goes outside until the danger has passed.
- 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: squash vine borer, squash bug, striped cucumber beetle. Diseases and disorders: powdery mildew, bacterial wilt.
- Harvest (from about Aug 1 – Aug 31). Winter Squash takes 80-110 days to reach harvest. Needs the whole season - direct sow only where you have 100+ frost-free days. Cure 10 days in warmth after harvest for storage.
Figures come from our crop data; dates use Minnesota’s average frost dates. More in the full winter squash growing guide.
Winter Squash planting dates by USDA zone in Minnesota
Minnesota spans USDA zones 3a, 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 winter squash dates shift with them.
When to plant winter squash in nearby states
Questions gardeners in Minnesota ask
When is the best time to plant winter squash in Minnesota?
Plant winter squash transplants outdoors in Minnesota between May 6 and May 23. That timing is set by Minnesota's average last spring frost of May 6.
When should I start winter squash seeds indoors in Minnesota?
Start seeds indoors between April 8 and April 22, about 3 weeks before the last frost, so the seedlings are ready to plant out from May 6.
What is the latest I can plant winter squash in Minnesota?
About July 10. Winter squash needs at least 80 days to mature, and frost around September 28 ends the season, so later plantings risk being cut short.
When will winter squash planted in Minnesota be ready to harvest?
Planted on time, winter squash is usually ready from about August 1 to August 31, 80-110 days after planting.
When is the last frost in Minnesota?
On average around May 6, with the first fall frost around September 28 - about 145 frost-free days. Your town may differ by two weeks or more.