đWhen to Plant Summer Squash in USDA Zone 4b (2026 Guide)
Prolific producer. Wait until frost danger has fully passed. Here is the warm-season planting schedule for summer squash in zone 4b (covering areas like Minneapolis MN, Burlington VT). All dates are based on 2026 frost data for your zone.
Start Seeds Indoors
Apr 14
Direct sow or transplant
May 12
Harvest From
Jul 1
Because summer squash is a warm-season crop that frost will kill, wait until about May 12 in zone 4b â safely after the average last frost on May 5.
- Type: Warm-season
- Method: Direct sow or transplant
- Days to harvest: 50
- Spacing: 24" apart
- Sun: Full sun
- Zone 4b frost: May 5 â Oct 1
- Season length: ~149 days
- Companions: corn, beans, nasturtium
Growing summer squash in zone 4b
Zone 4b has an average last spring frost around May 5 and a first fall frost around Oct 1, giving roughly 149 frost-free growing days. That window comfortably fits summer squash's 50-day cycle, with room for a second succession planting if you time it right.
Get a head start by sowing seeds indoors around Apr 14, roughly 3 weeks before your last frost. Move the seedlings outside around May 12. Give each plant about 24 inches of space in full sun.
Zone 4b specific growing notes
In zone 4b (Minneapolis MN, Burlington VT), your 149-day growing season means summer squash should be planted only after the soil has thoroughly warmed. Warm-season crops like summer squash need soil temperatures of at least 60°F. In zone 4b's climate, using black plastic mulch can warm the soil 2-3 weeks earlier.
Your first fall frost around Oct 1 means your last possible harvest is roughly late Oct. For a continuous supply, consider succession planting every 2-3 weeks from May 12 through mid-season.
Pro tip for summer squash
Pick at 6-8 inches for best flavor and tender skinâoversized squash turns seedy and woody. Check plants every other day during peak season: a zucchini can go from 4 to 12 inches in 48 hours.
Troubleshooting summer squash
Squash vine borers kill plants by tunneling inside stems. The adult moth lays eggs at the stem base. Wrap the lower 2 inches of stems with aluminum foil at transplant time, or inject Bt into stems at first sign of frass (sawdust-like droppings).
Growing summer squash in containers
Bush varieties in 10-gallon containers or large grow bags work well. Do not even try vining types in containersâa single plant can sprawl 15+ feet. One container plant feeds a family of 4.
Can you plant summer squash twice a year?
Yesâsow a second round in early summer (late June in zones 5+) to extend harvest into fall. Squash vine borers are less active later in summer, so second plantings often escape damage.
Frequently asked questions
When should I plant summer squash in zone 4b?
Direct sow or transplant around May 12. If starting from seed indoors, sow around Apr 14. Because summer squash is a warm-season crop that frost will kill, wait until about May 12 in zone 4b â safely after the average last frost on May 5.
How long does summer squash take to grow in zone 4b?
About 50 days from sowing to first harvest. A May 12 planting in zone 4b is typically ready to pick from around Jul 1. Zone 4b has about 149 frost-free days â plenty of time for a second succession planting.
How far apart should I space summer squash?
Space summer squash about 24 inches apart in full sun. This gives each plant enough room for roots to spread and leaves to catch sunlight without competing.
What is the best tip for growing summer squash?
Pick at 6-8 inches for best flavor and tender skinâoversized squash turns seedy and woody. Check plants every other day during peak season: a zucchini can go from 4 to 12 inches in 48 hours.
What are common problems with summer squash and how do I fix them?
Squash vine borers kill plants by tunneling inside stems. The adult moth lays eggs at the stem base. Wrap the lower 2 inches of stems with aluminum foil at transplant time, or inject Bt into stems at first sign of frass (sawdust-like droppings).
Can I grow summer squash in a container?
Bush varieties in 10-gallon containers or large grow bags work well. Do not even try vining types in containersâa single plant can sprawl 15+ feet. One container plant feeds a family of 4.
Can I plant a second crop of summer squash for fall harvest?
Yesâsow a second round in early summer (late June in zones 5+) to extend harvest into fall. Squash vine borers are less active later in summer, so second plantings often escape damage.
What grows well next to summer squash?
Good companion plants for summer squash are corn, beans, nasturtium. Avoid planting near cool-season crops that have different watering needs. Summer Squash also benefits from crop rotation â do not plant it in the same spot year after year.