When to Plant Squash (Summer) in Wyoming
Zucchini and yellow squash are the garden's most generous producers. You'll be sharing with neighbors by midsummer.
The Short Answer
Wyoming Frost Dates
Your planting dates depend on which part of Wyoming you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Eastern Wyoming | 4a, 4b, 5a | May 10 - May 30 | Sep 10 - Sep 25 |
| Western Wyoming | 3a, 3b, 4a | May 25 - Jun 15 | Aug 25 - Sep 15 |
| Southern Wyoming | 4b, 5a, 5b | May 15 - Jun 1 | Sep 5 - Sep 20 |
Squash (Summer) Planting Schedule for Wyoming
Eastern Wyoming (Zones 4a, 4b, 5a)
Average last frost: May 10 - May 30 · Average first frost: Sep 10 - Sep 25
Western Wyoming (Zones 3a, 3b, 4a)
Average last frost: May 25 - Jun 15 · Average first frost: Aug 25 - Sep 15
Southern Wyoming (Zones 4b, 5a, 5b)
Average last frost: May 15 - Jun 1 · Average first frost: Sep 5 - Sep 20
Growing Squash (Summer) in Wyoming
Squash (Summer) in Wyoming's Climate
Summer squash (zucchini, yellow squash) is one of the most productive crops for short-season gardens — 45-60 day maturity means even 100-day seasons produce abundant harvests. Direct sow after soil reaches 60°F. Two or three plants produce more squash than most families can eat. Squash vine borer is less prevalent in cold zones, reducing the most frustrating squash pest.
Soil Considerations for Wyoming
Alkaline, thin soils. Dry climate means little organic matter naturally. Wind erosion a significant challenge. Heavy amendment needed. Make sure soil has warmed to at least 60°F before planting squash (summer) outside.
Wyoming Climate & Growing Season
Short growing season. Very windy — wind protection essential for gardens. Low humidity. Cool nights even in summer at elevation. Squash (Summer) cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Wyoming: Eastern Wyoming (4a, 4b, 5a) has a last frost around May 10 - May 30, while Southern Wyoming (4b, 5a, 5b) sees frost end around May 15 - Jun 1. This difference matters for squash (summer) — transplant timing shifts by several weeks across the state.
Growing Tips
Harvest when fruits are 6-8 inches long for best flavor. Larger squash become seedy and tough.
Companion Planting
Plant squash (summer) alongside these companions for better growth:
Keep squash (summer) away from:
The Bottom Line
Last reviewed: March 29, 2026