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When to Plant Borage in Clermont 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.

Clermont County, Ohio is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 22, giving you a growing season of approximately 188 days.

At an elevation of 798 feet, Clermont County receives approximately 30.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Borage during the growing season.

Clermont County, OH (Zone 6a) Moderate season
188 days
Last Spring Frost April 17
188 growing days
First Fall Frost October 22

Clermont County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (91 days to spare)
Start indoors: Mar 7 Transplant: Apr 4 🍅 Harvest: May 30 – Jul 18
Recommended (50%) ✓ Fits season (90 days to spare)
Start indoors: Mar 13 Transplant: Apr 10 🍅 Harvest: Jun 5 – Jul 24
Safe Start (90%) ✓ Fits season (86 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
0.7″/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

Borage needs ~921 GDD — county provides 3,149 GDD Excellent fit

Borage Planting Timeline โ€” Clermont County, OH

Borage Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 โ€“ Mar 27
Transplant Outdoors April 10 Apr 10 โ€“ Apr 24
Direct Sow April 3 Apr 3 โ€“ Apr 24
Fall Sowing August 13 Aug 13 โ€“ Aug 27
Harvest June 5 Jun 5 โ€“ Jul 24

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 Clermont 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 Clermont County, OH?

Clermont County is in Zone 6a with an average last frost of April 17. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clermont County, OH?

Clermont County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 22.

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Plan Your Garden with Confidence

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