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When to Plant Borage in Lake County, CO

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.

Lake County, Colorado is in USDA Zone 4a. The average last spring frost is June 21 and the first fall frost is August 30, giving you a growing season of approximately 70 days.

At an elevation of 7,687 feet, Lake County receives approximately 21.2 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Borage to ensure they mature before fall.

Lake County, CO (Zone 4a) Very short season
70 days
Last Spring Frost June 21
70 growing days
First Fall Frost August 30

Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 5 Transplant: Jun 9 🍅 Harvest: Aug 4 – Sep 22
Recommended (50%) ✗ May not fit
Start indoors: May 10 Transplant: Jun 14 🍅 Harvest: Aug 9 – Sep 27
Safe Start (90%) ✗ May not fit
Start indoors: May 16 Transplant: Jun 20 🍅 Harvest: Aug 15 – Oct 3

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
1.3″/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 ~674 GDD — county provides 857 GDD Good fit

Borage Planting Timeline โ€” Lake County, CO

Borage Planting Calendar

Activity When Date Range
Start Indoors May 10 May 10 โ€“ May 24
Transplant Outdoors June 14 Jun 14 โ€“ Jun 28
Direct Sow June 14 Jun 14 โ€“ Jul 5
Fall Sowing June 7 Jun 7 โ€“ Jun 21
Harvest August 9 Aug 9 โ€“ Sep 27

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Start Indoors
June Transplant Outdoors Direct Sow Fall Sowing
July Direct Sow
August Harvest
September Harvest
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 4a

Growing Season

70 days

Growing Tips for Lake 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 Lake County, CO?

Lake County is in Zone 4a with an average last frost of June 21. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lake County, CO?

Lake County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 21 and first fall frost is August 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lake County gardeners in Zone 4a 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 Lake County, CO. Local conditions may vary. Last updated: April 2026.