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When to Plant Borage in Cass 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.

Cass County, Missouri is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 22, giving you a growing season of approximately 191 days.

At an elevation of 910 feet, Cass County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Borage during the growing season.

Cass County, MO (Zone 6a) Moderate season
191 days
Last Spring Frost April 14
191 growing days
First Fall Frost October 22

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (93 days to spare)
Start indoors: Mar 3 Transplant: Mar 31 🍅 Harvest: May 26 – Jul 14
Recommended (50%) ✓ Fits season (93 days to spare)
Start indoors: Mar 10 Transplant: Apr 7 🍅 Harvest: Jun 2 – Jul 21
Safe Start (90%) ✓ Fits season (90 days to spare)
Start indoors: Mar 27 Transplant: Apr 24 🍅 Harvest: Jun 19 – Aug 7

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
Borage needs ~839 GDD — county provides 2,912 GDD Excellent fit

Borage Planting Timeline โ€” Cass County, MO

Borage Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors April 7 Apr 7 โ€“ Apr 21
Direct Sow March 31 Mar 31 โ€“ Apr 21
Fall Sowing August 13 Aug 13 โ€“ Aug 27
Harvest June 2 Jun 2 โ€“ Jul 21

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors Direct Sow
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

191 days

Growing Tips for Cass 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 Cass County, MO?

Cass County is in Zone 6a with an average last frost of April 14. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cass County, MO?

Cass County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 22.

๐ŸŒฑ

Plan Your Garden with Confidence

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