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When to Plant Borage in Clear Creek 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.

Clear Creek County, Colorado is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 6,538 feet, Clear Creek County receives approximately 24.6 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.

Clear Creek County, CO (Zone 4b) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26

Clear Creek County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 21 – Aug 9
Recommended (50%) ✓ Fits season (37 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jul 2 – Aug 20
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Apr 29 Transplant: Jun 3 🍅 Harvest: Jul 29 – Sep 16

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 Clear Creek County

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

Soil pH

Your soil pH (6.8โ€“8.1) is more alkaline than Borage prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Borage.

How to Plant Borage

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Borage

3
successive plantings in your 135-day season

Sow every 5.7 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Jul 04.

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 8/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Borage

Borage needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Borage Needs Rainfall You Supplement Action
Jan โ€” 1.9" 0" โ„๏ธ Dormant
Feb โ€” 1.5" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr โ€” 2.7" 0" โ„๏ธ Dormant
May 2.2" 2.7" 0" โœ… Rainfall sufficient
Jun 2.2" 1.7" 0.5" ๐Ÿ’ง Light watering
Jul 2.2" 2.4" 0" โœ… Rainfall sufficient
Aug 2.2" 2.4" 0" โœ… Rainfall sufficient
Sep 2.2" 2.1" 0.1" ๐Ÿ’ง Light watering
Oct โ€” 2.3" 0" โ„๏ธ Dormant
Nov โ€” 1.9" 0" โ„๏ธ Dormant
Dec โ€” 1.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Clear Creek County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Borage Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Borage needs ~674 GDD — county provides 1,653 GDD Excellent fit

Borage Planting Timeline โ€” Clear Creek County, CO

Borage Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 โ€“ Apr 16
Transplant Outdoors May 7 May 7 โ€“ May 21
Direct Sow May 7 May 7 โ€“ May 28
Harvest July 2 Jul 2 โ€“ Aug 20
Fall Sowing July 4 Jul 4 โ€“ Jul 18

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

Month-by-Month Timeline

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

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

135 days in Clear Creek County

Growing Tips for Borage in Clear Creek County

Direct sow Borage outdoors after May 14 in Clear Creek 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Borage in Clear Creek County, CO?

Clear Creek County is in Zone 4b with an average last frost of May 14. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clear Creek County, CO?

Clear Creek County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

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