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When to Plant Borage in Ogle County, IL

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.

Ogle County, Illinois is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 13, giving you a growing season of approximately 173 days.

At an elevation of 890 feet, Ogle County receives approximately 39.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Borage during the growing season.

Ogle County, IL (Zone 5a) Moderate season
173 days
Last Spring Frost April 23
173 growing days
First Fall Frost October 13

Ogle County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Mar 14 Transplant: Apr 11 🍅 Harvest: Jun 6 – Jul 25
Recommended (50%) ✓ Fits season (75 days to spare)
Start indoors: Mar 19 Transplant: Apr 16 🍅 Harvest: Jun 11 – Jul 30
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Mar 30 Transplant: Apr 27 🍅 Harvest: Jun 22 – Aug 10

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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Borage needs ~756 GDD — county provides 2,378 GDD Excellent fit

Borage Planting Timeline โ€” Ogle County, IL

Borage Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 โ€“ Apr 2
Transplant Outdoors April 16 Apr 16 โ€“ Apr 30
Direct Sow April 9 Apr 9 โ€“ Apr 30
Fall Sowing August 4 Aug 4 โ€“ Aug 18
Harvest June 11 Jun 11 โ€“ Jul 30

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors 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 5a

Growing Season

173 days

Growing Tips for Ogle 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 Ogle County, IL?

Ogle County is in Zone 5a with an average last frost of April 23. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ogle County, IL?

Ogle County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 13.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Ogle County gardeners in Zone 5a 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 Ogle County, IL. Local conditions may vary. Last updated: April 2026.