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When to Plant Borage in Hamilton County, OH

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.

Hamilton County, Ohio is in USDA Zone 6a. The average last spring frost is April 16 and the first fall frost is October 21, giving you a growing season of approximately 188 days.

At an elevation of 735 feet, Hamilton County receives approximately 38.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Borage during the growing season.

Hamilton County, OH (Zone 6a) Moderate season
188 days
Last Spring Frost April 16
188 growing days
First Fall Frost October 21

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (91 days to spare)
Start indoors: Mar 6 Transplant: Apr 3 🍅 Harvest: May 29 – Jul 17
Recommended (50%) ✓ Fits season (90 days to spare)
Start indoors: Mar 12 Transplant: Apr 9 🍅 Harvest: Jun 4 – Jul 23
Safe Start (90%) ✓ Fits season (84 days to spare)
Start indoors: Apr 2 Transplant: Apr 30 🍅 Harvest: Jun 25 – Aug 13

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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Borage needs ~1,004 GDD — county provides 3,431 GDD Excellent fit

Borage Planting Timeline โ€” Hamilton County, OH

Borage Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 โ€“ Mar 26
Transplant Outdoors April 9 Apr 9 โ€“ Apr 23
Direct Sow April 2 Apr 2 โ€“ Apr 23
Fall Sowing August 12 Aug 12 โ€“ Aug 26
Harvest June 4 Jun 4 โ€“ Jul 23

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 6a

Growing Season

188 days

Growing Tips for Hamilton 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 Hamilton County, OH?

Hamilton County is in Zone 6a with an average last frost of April 16. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Hamilton County, OH?

Hamilton County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 16 and first fall frost is October 21.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Hamilton County gardeners in Zone 6a 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 Hamilton County, OH. Local conditions may vary. Last updated: April 2026.