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When to Plant Borage in Charlevoix County, MI

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.

Charlevoix County, Michigan is in USDA Zone 5a. The average last spring frost is May 5 and the first fall frost is October 21, giving you a growing season of approximately 169 days.

At an elevation of 821 feet, Charlevoix County receives approximately 41.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Borage to ensure they mature before fall.

Charlevoix County, MI (Zone 5a) Moderate season
169 days
Last Spring Frost May 5
169 growing days
First Fall Frost October 21

Charlevoix County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Mar 23 Transplant: Apr 20 🍅 Harvest: Jun 15 – Aug 3
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Mar 31 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 11
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Apr 15 Transplant: May 13 🍅 Harvest: Jul 8 – Aug 26

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 Charlevoix County

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

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) 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

3
successive plantings in your 169-day season

Sow every 5.7 weeks. Last sowing by Aug 22 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/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

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€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 2.1" 0" โ„๏ธ Dormant
Mar โ€” 2.8" 0" โ„๏ธ Dormant
Apr โ€” 3.7" 0" โ„๏ธ Dormant
May 2.2" 5.3" 0" โœ… Rainfall sufficient
Jun 2.2" 5.3" 0" โœ… Rainfall sufficient
Jul 2.2" 4.2" 0" โœ… Rainfall sufficient
Aug 2.2" 4.7" 0" โœ… Rainfall sufficient
Sep 2.2" 4.1" 0" โœ… Rainfall sufficient
Oct 2.2" 2.8" 0" โœ… Rainfall sufficient
Nov โ€” 2.7" 0" โ„๏ธ Dormant
Dec โ€” 2.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Charlevoix 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 ~715 GDD — county provides 2,197 GDD Excellent fit

Borage Planting Timeline โ€” Charlevoix County, MI

Borage Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 โ€“ Apr 14
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Direct Sow April 21 Apr 21 โ€“ May 12
Harvest June 23 Jun 23 โ€“ Aug 11
Fall Sowing August 12 Aug 12 โ€“ Aug 26

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

Month-by-Month Timeline

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

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

169 days in Charlevoix County

Growing Tips for Borage in Charlevoix County

Direct sow Borage outdoors after May 05 in Charlevoix 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 Charlevoix County, MI?

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

What planting zone is Charlevoix County, MI?

Charlevoix County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 5 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

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