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When to Plant Spinach in Asotin County, WA

Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Asotin County, Washington is in USDA Zone 6b. The average last spring frost is May 9 and the first fall frost is September 30, giving you a growing season of approximately 144 days.

At an elevation of 2,029 feet, Asotin County receives approximately 14 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Spinach during the growing season. With low rainfall, drip irrigation is essential for growing Spinach successfully. Mulch heavily to conserve soil moisture.

Asotin County, WA (Zone 6b) Short season
144 days
Last Spring Frost May 9
144 growing days
First Fall Frost September 30

Asotin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jun 2 – Aug 4
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 13 – Aug 15
Safe Start (90%) ✓ Fits season (39 days to spare)
Start indoors: May 2 Transplant: Jun 6 🍅 Harvest: Jul 11 – Sep 12

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 758 gal / 100 sq ft
Spinach needs ~584 GDD — county provides 1,980 GDD Excellent fit

Spinach Planting Timeline โ€” Asotin County, WA

Spinach Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 โ€“ Apr 18
Transplant Outdoors May 9 May 9 โ€“ May 23
Direct Sow April 25 Apr 25 โ€“ May 16
Fall Sowing July 22 Jul 22 โ€“ Aug 5
Harvest June 13 Jun 13 โ€“ Aug 15

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August Fall Sowing Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

35โ€“50 days

Soil pH

6.5 โ€“ 7.5

USDA Zone

Zone 6b

Growing Season

144 days

Growing Tips for Asotin County

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Companion Planting

Good Companions

Level Up Your Garden

๐ŸŒพ Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35ยฐF, under 45% humidity.

Wind pollinated โ€” isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in Asotin County, WA?

Asotin County is in Zone 6b with an average last frost of May 9. Plan your Spinach planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Asotin County, WA?

Asotin County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 9 and first fall frost is September 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Asotin County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

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Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Asotin County, WA. Local conditions may vary. Last updated: April 2026.