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When to Plant Borage in Brown 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.

Brown County, Illinois is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 868 feet, Brown County receives approximately 36.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Borage during the growing season.

Brown County, IL (Zone 5b) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Brown County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (84 days to spare)
Start indoors: Mar 8 Transplant: Apr 5 🍅 Harvest: May 31 – Jul 19
Recommended (50%) ✓ Fits season (84 days to spare)
Start indoors: Mar 13 Transplant: Apr 10 🍅 Harvest: Jun 5 – Jul 24
Safe Start (90%) ✓ Fits season (84 days to spare)
Start indoors: Mar 26 Transplant: Apr 23 🍅 Harvest: Jun 18 – Aug 6

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 Brown County

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

Soil pH

Your soil pH (6.3โ€“6.8) is within Borage's preferred range (6.0โ€“7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) 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 182-day season

Sow every 5.7 weeks. Last sowing by Aug 17 to harvest before frost.

For a dedicated fall crop, sow by Aug 07.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Borage needs ~798 GDD — county provides 2,639 GDD Excellent fit

Borage Planting Timeline โ€” Brown County, IL

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 7 Aug 7 โ€“ Aug 21
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

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: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

182 days in Brown County

Growing Tips for Borage in Brown County

Direct sow Borage outdoors after April 17 in Brown 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Borage in Brown County, IL?

Brown County is in Zone 5b 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 Brown County, IL?

Brown County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 17 and first fall frost is October 16.

๐ŸŒฑ

Plan Your Garden with Confidence

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