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When to Plant Echinacea in Grant County, WA

Echinacea (purple coneflower) is a native prairie perennial valued for its immune-supporting properties and beautiful daisy-like flowers that attract pollinators.

Grant County, Washington is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 10, giving you a growing season of approximately 164 days.

At an elevation of 3,122 feet, Grant County receives approximately 17.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Echinacea during the growing season. With low rainfall, drip irrigation is essential for growing Echinacea successfully. Mulch heavily to conserve soil moisture.

Grant County, WA (Zone 6b) Moderate season
164 days
Last Spring Frost April 29
164 growing days
First Fall Frost October 10

Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 21 🍅 Harvest: Aug 25 – Nov 3
Recommended (50%) ✗ May not fit
Transplant: May 6 🍅 Harvest: Sep 9 – Nov 18
Safe Start (90%) ✗ May not fit
Transplant: May 26 🍅 Harvest: Sep 29 – Dec 8

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
0.5″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 72 gal / 100 sq ft
Echinacea needs ~2,738 GDD — county provides 2,993 GDD Good fit

Echinacea Planting Timeline โ€” Grant County, WA

Echinacea Planting Calendar

Activity When Date Range
Transplant Outdoors May 6 May 6 โ€“ May 20
Harvest September 9 Sep 9 โ€“ Nov 18

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June โ€”
July โ€”
August โ€”
September Harvest
October Harvest
November Harvest
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

120โ€“180 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6b

Growing Season

164 days

Growing Tips for Grant County

Start seeds indoors 8-10 weeks before last frost or direct sow in fall for spring germination. Seeds need cold stratification. Deadhead to prolong blooming or leave seed heads for birds.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Echinacea in Grant County, WA?

Grant County is in Zone 6b with an average last frost of April 29. Plan your Echinacea planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grant County, WA?

Grant County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is April 29 and first fall frost is October 10.

๐ŸŒฑ

Plan Your Garden with Confidence

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

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