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When to Plant Borage in Randolph County, MO

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.

Randolph County, Missouri is in USDA Zone 5b. The average last spring frost is April 15 and the first fall frost is October 18, giving you a growing season of approximately 186 days.

At an elevation of 1,243 feet, Randolph County receives approximately 33.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Borage during the growing season.

Randolph County, MO (Zone 5b) Moderate season
186 days
Last Spring Frost April 15
186 growing days
First Fall Frost October 18

Randolph County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Mar 6 Transplant: Apr 3 🍅 Harvest: May 29 – Jul 17
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Mar 11 Transplant: Apr 8 🍅 Harvest: Jun 3 – Jul 22
Safe Start (90%) ✓ Fits season (88 days to spare)
Start indoors: Mar 25 Transplant: Apr 22 🍅 Harvest: Jun 17 – Aug 5

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
0.8″/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 ~756 GDD — county provides 2,557 GDD Excellent fit

Borage Planting Timeline โ€” Randolph County, MO

Borage Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 โ€“ Mar 25
Transplant Outdoors April 8 Apr 8 โ€“ Apr 22
Direct Sow April 1 Apr 1 โ€“ Apr 22
Fall Sowing August 9 Aug 9 โ€“ Aug 23
Harvest June 3 Jun 3 โ€“ Jul 22

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 5b

Growing Season

186 days

Growing Tips for Randolph 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 Randolph County, MO?

Randolph County is in Zone 5b with an average last frost of April 15. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Randolph County, MO?

Randolph County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 15 and first fall frost is October 18.

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Plan Your Garden with Confidence

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