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When to Plant Strawberries in Jefferson County, MT

Jefferson County, Montana Zone 5a May

May in the garden — Jefferson County, Montana

A quick May briefing for Jefferson County, Montana gardeners — what's urgent, what's next, and what can wait.

Avg. last frost June 15
Avg. first frost September 7
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14.8 hrs

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Strawberries are a beloved perennial fruit available as June-bearing, ever-bearing, and day-neutral types. They are one of the easiest fruits to grow in containers or garden beds.

Jefferson County, Montana is in USDA Zone 5a. The average last spring frost is June 15 and the first fall frost is September 7, giving you a growing season of approximately 84 days.

At an elevation of 7,214 feet, Jefferson County receives approximately 21.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Strawberries to ensure they mature before fall.

Jefferson County, MT (Zone 5a) Very short season
84 days
Last Spring Frost June 15
84 growing days
First Fall Frost September 7

Jefferson County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 30 🍅 Harvest: Sep 29 – Dec 15
Recommended (50%) ✗ May not fit
Transplant: Jul 6 🍅 Harvest: Oct 5 – Dec 21
Safe Start (90%) ✗ May not fit
Transplant: Jul 14 🍅 Harvest: Oct 13 – Dec 29

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 Jefferson County

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

Soil pH

Your soil pH (6.4–7.9) is more alkaline than Strawberries prefers (5.5–6.8). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Strawberries.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Strawberries.

How to Plant Strawberries

12"
Between Plants
24"
Between Rows

How Much Strawberries to Grow

1 lb
Average yield per plant
10
Plants per person
20 sq ft
Space per person

For a family of 4, plant approximately 40 strawberries plants in about 80 sq ft. In Jefferson County's 84-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 202 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Strawberries

Strawberries needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Strawberries Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Strawberries 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.

Strawberries needs ~2,616 GDD — county provides 966 GDD May not mature

Strawberries Planting Timeline — Jefferson County, MT

Strawberries Planting Calendar

Activity When Date Range
Transplant Outdoors July 6 Jul 6 – Jul 20
Harvest October 5 Oct 5 – Dec 21

· 12" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July Transplant Outdoors
August
September
October Harvest
November Harvest
December Harvest

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–365 days

🧪 Soil pH

Needs 5.5–6.8 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

84 days in Jefferson County

Growing Tips for Strawberries in Jefferson County

Direct sow Strawberries outdoors after June 15 in Jefferson County when soil has warmed and frost danger has passed.

Your 84.0-day growing season in Jefferson County is tight for Strawberries (90.0-365.0 days to maturity). Start indoors and choose early-maturing varieties.

Jefferson County receives only 22" of rain annually. Strawberries needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant with crowns at soil level. Remove runners the first year to strengthen plants. Mulch with straw to keep fruit clean and suppress weeds. Renovate June-bearing beds after harvest.

Recommended Strawberries Varieties for Jefferson County

June-bearing varieties suited for northern climates

Sparkle Jewel Earliglow

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Broccoli

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Strawberries in Jefferson County, MT?

Jefferson County is in Zone 5a with an average last frost of June 15. Plan your Strawberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, MT?

Jefferson County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 15 and first fall frost is September 7.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 5a). 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 Jefferson County, MT. Local conditions may vary. Last updated: May 2026.

Sources & credits

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