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When to Plant Borage in Fergus County, MT

Fergus County, Montana Zone 4a April

Your April game plan for Fergus County, Montana

Each item below is timed to Fergus County, Montana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 20
Avg. first frost September 20
Soil temp (4") 21°F
Watering High
Pest pressure Low
Daylight 13.4 hrs
A few tasks this April that'll pay off in May
  • Transplants going out: borage
  • Direct-sowing: borage

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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.

Fergus County, Montana is in USDA Zone 4a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.

At an elevation of 6,957 feet, Fergus County receives approximately 12 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Borage to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Borage successfully. Mulch heavily to conserve soil moisture.

Fergus County, MT (Zone 4a) Short season
123 days
Last Spring Frost May 20
123 growing days
First Fall Frost September 20
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Fergus County Soil Profile

Soil Type

Loam

Soil pH

6.4-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jul 2 – Aug 20
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 8 – Aug 26
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Jul 25 – Sep 12

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 Fergus County

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

Soil pH

Your soil pH (6.4–8.0) is more alkaline than Borage prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). 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

2
successive plantings in your 123-day season

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

For a dedicated fall crop, sow by Jun 28.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 119 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 0.8" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 2.2" 1.3" 0.9" 💧 Light watering
Jun 2.2" 0.7" 1.5" 🚿 Regular watering
Jul 2.2" 1.1" 1.1" 🚿 Regular watering
Aug 2.2" 1.3" 0.9" 💧 Light watering
Sep 2.2" 0.8" 1.4" 🚿 Regular watering
Oct 1.2" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Fergus 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 ~550 GDD — county provides 1,230 GDD Excellent fit

Borage Planting Timeline — Fergus County, MT

Borage Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 13 May 13 – May 27
Direct Sow May 13 May 13 – Jun 3
Harvest July 8 Jul 8 – Aug 26
Fall Sowing June 28 Jun 28 – Jul 12

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Direct Sow Fall Sowing
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 · Only during dry spells

📅 Days to Maturity

50–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

123 days in Fergus County

Growing Tips for Borage in Fergus County

Direct sow Borage outdoors after May 20 in Fergus 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 Fergus County, MT?

Fergus County is in Zone 4a with an average last frost of May 20. Plan your Borage planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fergus County, MT?

Fergus County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 20 and first fall frost is September 20.

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Your Fergus County Garden Planner — Free

A 24-page printable planner built for Fergus 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 Fergus County, MT. 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.