Planting Guides
When to Plant Squash in Minneapolis: Complete Guide + Best Varieties for Zone 4a
Minneapolis, Minnesota
USDA Zone 4a
Last Frost: May 15
Last updated: October 30, 2025
Plant squash in Minneapolis after May 14 last frost. Summer types need 45-60 days, winter types 80-100 days before September 29 first frost.
— Image © PlantReference.org 2026
Quick Answer
Plant summer squash in Minneapolis after May 14 last frost for 45-60 day harvest. Start winter squash indoors April 20, transplant May 20-25 for September maturity.
TL;DR
Minneapolis squash timing: Plant summer squash like Cucurbita pepo 'Black Beauty' after May 14 for July harvest. Winter squash varieties need planting by June 1 to mature before September 29 frost. Zone 4a challenge: Only 138-day growing season limits winter squash to early varieties like Delicata.
Frequently Asked Questions
When is the last date I can plant squash in Minneapolis?
For summer squash varieties like Cucurbita pepo 'Black Beauty', the absolute latest planting date in Minneapolis is July 15. This allows 45-55 days to maturity before the average first frost on September 29. Winter squash varieties must be planted by June 1 at the latest, as they require 80-100+ days to reach maturity. Planting later than these dates risks losing your crop to early fall frosts, which are common in Minneapolis Zone 4a climate.
Which squash varieties work best in Minneapolis's short growing season?
The best squash varieties for Minneapolis are early-maturing types that fit within our 138-day growing season. Summer squash varieties like Cucurbita pepo 'Black Beauty' (45-55 days), Cucurbita pepo 'Pattypan' (50-60 days), and Cucurbita pepo 'Yellow Crookneck' (50-60 days) are excellent choices. For winter squash, stick with Cucurbita pepo 'Delicata' (80-90 days) and Cucurbita pepo 'Acorn' (85-95 days). Avoid long-season varieties like Cucurbita moschata 'Butternut' unless you start them indoors and use season extension techniques.
How do I protect squash plants from Minneapolis's unpredictable spring weather?
Minneapolis spring weather can be challenging with late frosts and cool temperatures. Use row covers when nighttime temperatures drop below 50°F (10°C), even after the average last frost date of May 14. Wall-of-water plant protectors work well for individual plants. Black plastic mulch helps warm the soil faster in spring. Keep row covers handy through early June, as surprise cold snaps can damage tender squash plants. Remove covers during flowering to allow pollination.
What's the biggest pest problem for squash in Minneapolis?
Squash vine borers are the most destructive pest for Minneapolis squash growers. These clear-wing moths lay eggs at the base of stems in late June through July. Look for small holes with sawdust-like frass around stem bases. Prevention includes using row covers until flowering, wrapping stems with aluminum foil, and choosing resistant varieties. If you find borers, slit the stem with a clean knife, remove the white larva, and mound soil over the wound to encourage new root growth from the stem.
Can I grow winter squash varieties in containers in Minneapolis?
Yes, but choose compact varieties and large containers. Cucurbita pepo 'Delicata' and bush-type Cucurbita pepo 'Acorn' varieties work best in containers. Use containers at least 20-30 gallons in size with excellent drainage. Place containers in the warmest, sunniest location available. Container plants dry out faster and may need daily watering in Minneapolis summers. Start seeds indoors in April for transplanting after May 20 to maximize the growing season. Smaller containers limit root growth and reduce yields significantly.
How do I know when winter squash is ready to harvest in Minneapolis?
Winter squash is ready when the stem becomes dry and corky, the skin hardens so you cannot puncture it with your fingernail, and the color deepens and becomes dull. The attached vines will begin dying back naturally. This typically occurs in Minneapolis from mid-September through early October, depending on variety and planting date. Cut the stem with pruning shears, leaving 1-2 inches attached to the fruit. Harvest before hard frost (usually September 29) even if slightly immature—they can continue ripening indoors in a warm location.
What should I do if my squash flowers aren't setting fruit?
Flower problems are common in Minneapolis's cool, cloudy springs. First, identify flower types—male flowers appear first (no small fruit at base), followed by female flowers (small squash visible at base). Both are needed for fruit production. Hand pollinate by transferring pollen from male flowers to female flowers using a small brush in early morning. Ensure adequate bee activity by planting nearby flowers. Excessive nitrogen fertilizer can cause all foliage growth with few flowers—reduce feeding if plants are overly vigorous but not flowering.
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Amanda Foster
Amanda came to gardening through an unexpected route—after developing chronic pain from rheumatoid arthritis in her late 20s, she started researching adaptive gardening techniques that would allow her to continue growing plants without aggravating her condition. Now based in Minneapolis, she writes about accessible gardening, raised bed designs for people with mobility challenges, and ergonomic tools that reduce strain. Amanda completed a certificate in sustainable urban agriculture and volunteers with a nonprofit that builds accessible community gardens. She grows vegetables, herbs, and flowers in waist-high raised beds she designed herself. Her writing focuses on practical solutions that work for real people with real limitations—whether that's arthritis, limited mobility, or just a bad back.
