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When to Plant Borage in Walla Walla County, WA

Borage is a self-seeding annual herb with star-shaped blue flowers that attract pollinators. Its leaves have a cucumber-like flavor and the flowers are edible.

Walla Walla County, Washington is in USDA Zone 6b. The average last spring frost is April 20 and the first fall frost is October 15, giving you a growing season of approximately 178 days.

At an elevation of 3,151 feet, Walla Walla County receives approximately 23.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Borage during the growing season.

Walla Walla County, WA (Zone 6b) Moderate season
178 days
Last Spring Frost April 20
178 growing days
First Fall Frost October 15

Walla Walla County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (89 days to spare)
Start indoors: Feb 27 Transplant: Mar 27 🍅 Harvest: May 22 – Jul 10
Recommended (50%) ✓ Fits season (80 days to spare)
Start indoors: Mar 16 Transplant: Apr 13 🍅 Harvest: Jun 8 – Jul 27
Safe Start (90%) ✓ Fits season (79 days to spare)
Start indoors: Apr 9 Transplant: May 7 🍅 Harvest: Jul 2 – Aug 20

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
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Borage needs ~756 GDD — county provides 2,447 GDD Excellent fit

Borage Planting Timeline โ€” Walla Walla County, WA

Borage Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors April 13 Apr 13 โ€“ Apr 27
Direct Sow April 6 Apr 6 โ€“ Apr 27
Fall Sowing August 6 Aug 6 โ€“ Aug 20
Harvest June 8 Jun 8 โ€“ Jul 27

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

50โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6b

Growing Season

178 days

Growing Tips for Walla Walla County

Direct sow in spring as borage does not transplant well. Allow some plants to go to seed for next year. Young leaves are best; older leaves become bristly.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Borage in Walla Walla County, WA?

Walla Walla County is in Zone 6b with an average last frost of April 20. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Walla Walla County, WA?

Walla Walla County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is April 20 and first fall frost is October 15.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Walla Walla 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 Walla Walla County, WA. Local conditions may vary. Last updated: April 2026.