Cool-Season Vegetable

When to Plant Spinach in Wyoming

Fast from seed to salad. Spinach bolts in heat, so plant early in spring and again in fall.

The Short Answer

Spinach are cold-tolerant and do well in Wyoming's humid climate. You can direct sow 6 weeks before your last frost — that's as early as May 10 - May 30 in Eastern Wyoming. Wyoming gardeners can also plant a fall crop. Alkaline, thin soils. Dry climate means little organic matter naturally. Wind erosion a significant...

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

Spinach Planting Schedule for Wyoming

Eastern Wyoming (Zones 4a, 4b, 5a)

Average last frost: May 10 - May 30 · Average first frost: Sep 10 - Sep 25

Direct Sow
6 wks before frost
Fall Planting
6 wks before first frost

Western Wyoming (Zones 3a, 3b, 4a)

Average last frost: May 25 - Jun 15 · Average first frost: Aug 25 - Sep 15

Direct Sow
6 wks before frost
Fall Planting
6 wks before first frost

Southern Wyoming (Zones 4b, 5a, 5b)

Average last frost: May 15 - Jun 1 · Average first frost: Sep 5 - Sep 20

Direct Sow
6 wks before frost
Fall Planting
6 wks before first frost

Growing Spinach in Wyoming

Spinach in Wyoming's Climate

Your cool climate extends the spinach season significantly compared to warmer zones. Direct sow as soon as soil thaws — spinach germinates in soil as cool as 35°F. Michigan and Minnesota gardeners may get 6-8 weeks of production before bolting versus 3-4 weeks in the South. Fall spinach from an August sowing is equally productive and often superior in quality.

Soil Considerations for Wyoming

Alkaline, thin soils. Dry climate means little organic matter naturally. Wind erosion a significant challenge. Heavy amendment needed.

Wyoming Climate & Growing Season

Short growing season. Very windy — wind protection essential for gardens. Low humidity. Cool nights even in summer at elevation. Spinach can handle frost well, which is an advantage in Wyoming's climate. You can push planting dates earlier in spring and extend into fall.

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 spinach — adjust your planting dates to match your specific region.

Growing Tips

Direct sow as soon as soil can be worked in spring. For fall, plant 6-8 weeks before first frost.

Companion Planting

Plant spinach alongside these companions for better growth:

Strawberries Peas Radishes

The Bottom Line

Spinach can be grown successfully across Wyoming, but your exact planting dates depend on which region you're in. Eastern Wyoming gardeners should plan around a May 10 - May 30 last frost, while those in Southern Wyoming can typically plant later. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Spinach Growing Guide National planting guide with all states Wyoming Planting Calendar All plants for Wyoming Spinach in Alabama Alabama planting dates Spinach in Alaska Alaska planting dates Spinach in Arizona Arizona planting dates Spinach in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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