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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.

Soil Compatibility in Clermont County

How your county's soil matches Borage's growing requirements.

Soil pH

Your soil pH (5.9โ€“7.0) overlaps with Borage's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Clermont County is excellent for Borage โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) โ€” Borage will thrive.

How to Plant Borage

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Borage

4
successive plantings in your 188-day season

Sow every 5.7 weeks. Last sowing by Aug 23 to harvest before frost.

For a dedicated fall crop, sow by Aug 13.

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

Monthly Watering Guide for Borage

Borage needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Borage Needs Rainfall You Supplement Action
Jan โ€” 1.1" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 1.8" 0" โ„๏ธ Dormant
Apr 2.2" 2.9" 0" โœ… Rainfall sufficient
May 2.2" 3.9" 0" โœ… Rainfall sufficient
Jun 2.2" 3.4" 0" โœ… Rainfall sufficient
Jul 2.2" 3.8" 0" โœ… Rainfall sufficient
Aug 2.2" 3.4" 0" โœ… Rainfall sufficient
Sep 2.2" 2.6" 0" โœ… Rainfall sufficient
Oct 2.2" 2.6" 0" โœ… Rainfall sufficient
Nov โ€” 1.8" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Clermont County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Borage Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

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
Harvest June 5 Jun 5 โ€“ Jul 24
Fall Sowing August 13 Aug 13 โ€“ Aug 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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

50โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

188 days in Clermont County

Growing Tips for Borage in Clermont County

Direct sow Borage outdoors after April 17 in Clermont County when soil has warmed and frost danger has passed.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

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.

๐ŸŒฑ

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.

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 Clermont County, OH. Local conditions may vary. Last updated: April 2026.