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When to Plant Spinach in Harney County, OR

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.

Harney County, Oregon is in USDA Zone 5b. The average last spring frost is June 17 and the first fall frost is September 6, giving you a growing season of approximately 81 days.

At an elevation of 679 feet, Harney County receives approximately 22.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Spinach during the growing season.

Harney County, OR (Zone 5b) Very short season
81 days
Last Spring Frost June 17
81 growing days
First Fall Frost September 6

Harney County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 8 Transplant: Jun 12 🍅 Harvest: Jul 17 – Sep 18
Recommended (50%) ✗ May not fit
Start indoors: May 13 Transplant: Jun 17 🍅 Harvest: Jul 22 – Sep 23
Safe Start (90%) ✗ May not fit
Start indoors: May 20 Transplant: Jun 24 🍅 Harvest: Jul 29 – Sep 30

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
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Spinach needs ~648 GDD — county provides 1,235 GDD Excellent fit

Spinach Planting Timeline โ€” Harney County, OR

Spinach Planting Calendar

Activity When Date Range
Start Indoors May 13 May 13 โ€“ May 27
Transplant Outdoors June 17 Jun 17 โ€“ Jul 1
Direct Sow June 3 Jun 3 โ€“ Jun 24
Fall Sowing June 28 Jun 28 โ€“ Jul 12
Harvest July 22 Jul 22 โ€“ Sep 23

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
July Transplant Outdoors Fall Sowing Harvest
August Harvest
September Harvest
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 5b

Growing Season

81 days

Growing Tips for Harney 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 Harney County, OR?

Harney County is in Zone 5b with an average last frost of June 17. Plan your Spinach planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Harney County, OR?

Harney County, Oregon is in USDA Hardiness Zone 5b. The average last spring frost is June 17 and first fall frost is September 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Harney County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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 Harney County, OR. Local conditions may vary. Last updated: April 2026.