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When to Plant Borage in Sibley County, MN

Sibley County, Minnesota Zone 4a April

This month in Sibley County, Minnesota

Your Sibley County, Minnesota garden is entering a new phase. Here's what's on the schedule for April and why each task matters now.

Avg. last frost April 30
Avg. first frost October 4
Soil temp (4") 39°F
Watering Moderate
Pest pressure Low
Daylight 13.3 hrs
  1. Get borage in the ground

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Outdoor sowing time: borage

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

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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.

Sibley County, Minnesota is in USDA Zone 4a. The average last spring frost is April 30 and the first fall frost is October 4, giving you a growing season of approximately 157 days.

At an elevation of 1,364 feet, Sibley County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Borage to ensure they mature before fall.

Sibley County, MN (Zone 4a) Moderate season
157 days
Last Spring Frost April 30
157 growing days
First Fall Frost October 4
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Sibley County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jun 12 – Jul 31
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jun 18 – Aug 6
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jul 3 – Aug 21

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 Sibley County

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

Soil pH

Your soil pH (6.1–6.9) is within Borage's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in Sibley County is excellent for Borage — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.5%) — 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 157-day season

Sow every 5.7 weeks. Last sowing by Aug 05 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

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

Water stress score is 6/10 — 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 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 2.2" 3.6" 0" ✅ Rainfall sufficient
May 2.2" 5" 0" ✅ Rainfall sufficient
Jun 2.2" 5.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3.7" 0" ✅ Rainfall sufficient
Sep 2.2" 3.7" 0" ✅ Rainfall sufficient
Oct 2.2" 3.2" 0" ✅ Rainfall sufficient
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sibley County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~632 GDD — county provides 1,805 GDD Excellent fit

Borage Planting Timeline — Sibley County, MN

Borage Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 23 Apr 23 – May 14
Harvest June 18 Jun 18 – Aug 6
Fall Sowing July 12 Jul 12 – Jul 26

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 4a

📆 Growing Season

157 days in Sibley County

Growing Tips for Borage in Sibley County

Direct sow Borage outdoors after April 30 in Sibley 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 Sibley County, MN?

Sibley County is in Zone 4a with an average last frost of April 30. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sibley County, MN?

Sibley County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is April 30 and first fall frost is October 4.

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Your Sibley County Garden Planner — Free

A 24-page printable planner built for Sibley 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.

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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 Sibley County, MN. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.