When to Plant Squash in Iowa
Direct Sow Outdoors
Saturday, March 14, 2026
State
Iowa
USDA Zones
4b, 5a, 5b, 6a
Avg Last Frost
Saturday, April 25, 2026
Cities Covered
934
Iowa Planting Schedule by Zone
Iowa spans 4 zones — find yours below for the most accurate dates.
| Zone | Last Frost | Direct Sow |
|---|---|---|
| 4b | Tuesday, May 5, 2026 | Tuesday, March 24, 2026 |
| 5a | Sunday, May 10, 2026 | Sunday, March 29, 2026 |
| 5b | Saturday, April 25, 2026 | Saturday, March 14, 2026 |
| 6a | Monday, April 20, 2026 | Monday, March 9, 2026 |
Dates based on average last frost. Check your local forecast before planting.
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Growing Squash in Iowa: Complete Guide
Squash (Cucurbita moschata) is a crop that grows best when sown directly in the garden. In Iowa, the right time to direct sow is around Saturday, March 14, 2026, once soil temperatures are consistently warm enough for germination.
Because Iowa stretches across 4 USDA hardiness zones (4b, 5a, 5b, 6a), planting windows can shift by as much as two to four weeks from one end of the state to the other. Gardeners in the warmer southern zones can start earlier, while those in cooler northern zones should wait until the zone table above shows their last frost has passed.
With 90 days to maturity, Squash fits comfortably within Iowa's growing season in most zones. In the warmest parts of the state, a second planting later in the season may be possible.
Squash requires full sun (6-8 hours) and regular (1 inch/week) moisture. Most of Iowa receives adequate sunlight during the growing season, though gardeners in humid eastern regions should watch for fungal issues and ensure good air circulation.
For the most precise planting dates tailored to your exact location, enter your ZIP code on our planting calendar or use the zone table above to find the schedule for your area of Iowa.
Frequently Asked Questions
When should I plant Squash in Iowa?
In Iowa, direct sow Squash outdoors around Saturday, March 14, 2026. Iowa spans zones 4b–6a, so gardeners in warmer zones can plant earlier.
What is the last frost date in Iowa?
Iowa spans 4 USDA zones (4b, 5a, 5b, 6a), so last frost dates vary by region. Riceville, Toeterville, Arlington (4b) sees frost until around Tuesday, May 5, 2026, while Council Bluffs, Carter Lake, Glenwood (6a) is frost-free much earlier.
How long does Squash take to grow in Iowa?
Squash takes about 90 days from transplant (or direct sow) to harvest. In Iowa's longer-season zones, a second planting in late summer may be possible.
What USDA zones does Iowa cover for Squash?
Iowa includes zones 4b, 5a, 5b, 6a. Squash grows well across all of these zones with adjusted timing — use the zone table above to find the right dates for your part of the state.
Find Precise Dates for Your City
Select a city for exact planting dates based on local frost records.