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When to Plant Borage in Itasca County, MN

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.

Itasca County, Minnesota is in USDA Zone 3a. The average last spring frost is May 10 and the first fall frost is October 1, giving you a growing season of approximately 144 days.

At an elevation of 506 feet, Itasca County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Borage to ensure they mature before fall.

Itasca County, MN (Zone 3a) Short season
144 days
Last Spring Frost May 10
144 growing days
First Fall Frost October 1

Itasca County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 21 – Aug 9
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Jun 28 – Aug 16
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Jul 15 – Sep 2

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 Itasca County

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

Soil pH

Your soil pH (6.0โ€“7.3) overlaps with Borage's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) โ€” Borage will thrive.

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 144-day season

Sow every 5.7 weeks. Last sowing by Aug 02 to harvest before frost.

For a dedicated fall crop, sow by Jul 09.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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€” 1.9" 0" โ„๏ธ Dormant
Mar โ€” 2.4" 0" โ„๏ธ Dormant
Apr โ€” 3.5" 0" โ„๏ธ Dormant
May 2.2" 5" 0" โœ… Rainfall sufficient
Jun 2.2" 5.5" 0" โœ… Rainfall sufficient
Jul 2.2" 4.7" 0" โœ… Rainfall sufficient
Aug 2.2" 4.4" 0" โœ… Rainfall sufficient
Sep 2.2" 3.1" 0" โœ… Rainfall sufficient
Oct 2.2" 3.1" 0" โœ… Rainfall sufficient
Nov โ€” 3.2" 0" โ„๏ธ Dormant
Dec โ€” 2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Itasca 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 ~591 GDD — county provides 1,548 GDD Excellent fit

Borage Planting Timeline โ€” Itasca County, MN

Borage Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 โ€“ Apr 12
Transplant Outdoors May 3 May 3 โ€“ May 17
Direct Sow May 3 May 3 โ€“ May 24
Harvest June 28 Jun 28 โ€“ Aug 16
Fall Sowing July 9 Jul 9 โ€“ Jul 23

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
May Transplant Outdoors Direct Sow
June Harvest
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: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 3a

๐Ÿ“† Growing Season

144 days in Itasca County

Growing Tips for Borage in Itasca County

Direct sow Borage outdoors after May 10 in Itasca 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 Itasca County, MN?

Itasca County is in Zone 3a with an average last frost of May 10. Plan your Borage planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Itasca County, MN?

Itasca County, Minnesota is in USDA Hardiness Zone 3a. The average last spring frost is May 10 and first fall frost is October 1.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Itasca County gardeners in Zone 3a 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 Itasca County, MN. Local conditions may vary. Last updated: April 2026.