When to plant Borage in Polk County, MN
Plant Borage in Polk County from May 4 to May 25 in spring. Polk County sits in USDA Zone 4a, with last frost around May 11 and first frost on October 1. A second sowing from July 9 to July 23 extends the harvest into fall.
When to Plant Borage in Polk 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.
Polk County, Minnesota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is October 1, giving you a growing season of approximately 143 days.
At an elevation of 1,053 feet, Polk County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Borage to ensure they mature before fall.
Polk County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.2
Drainage
Well Drained
Monthly Watering Guide for Borage
Borage needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Borage Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | — | 3.6" | 0" | ❄️ Dormant |
| May | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jun | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Sep | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Polk County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Borage Planting Timeline — Polk County, MN
Borage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 30 | Mar 30 – Apr 13 |
| Transplant Outdoors | May 4 | May 4 – May 18 |
| Direct Sow | May 4 | May 4 – May 25 |
| Harvest | June 29 | Jun 29 – Aug 17 |
| Fall Sowing | July 9 | Jul 9 – Jul 23 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Harvest |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
50–60 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
143 days in Polk County
Growing Tips for Polk 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
Check more plant combinations with our Companion Planting Checker →
Borage in Other Locations
Frequently Asked Questions
When should I plant Borage in Polk County, MN?
Polk County is in Zone 4a with an average last frost of May 11. Plan your Borage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Polk County, MN?
Polk County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is October 1.
When should I plant Borage in Polk County, MN?
In Polk County, MN, plant Borage after the last frost (around May 11) and before the first frost (around October 1). Best results when soil holds above 50°F.
What growing zone is Polk County, MN for Borage?
Polk County sits in USDA Zone 4a. Borage grows reliably in zones 3a through 11b, so it's a good fit here.
Can Borage grow in Polk County's climate?
Yes — Borage grows well in Polk County's temperate climate. Polk County averages a 143-day frost-free season, with last frost around May 11 and first frost around October 1.
Your Polk County Garden Planner — Free
A 22-page printable planner built for Polk County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.