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When to Plant Alpine Strawberries in Custer County, MT

Custer County, Montana Zone 4b May

Your May planting checklist for Custer County, Montana

May is a pivotal month for Custer County, Montana gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 14
Avg. first frost September 27
Soil temp (4") 36°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
June will be here before you know it — start on
  • Transplants going out: alpine strawberries

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Alpine strawberries are small, intensely flavored wild-type strawberries that fruit continuously from spring to frost. They do not produce runners and make excellent edging plants.

Custer County, Montana is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 27, giving you a growing season of approximately 136 days.

At an elevation of 5,983 feet, Custer County receives approximately 24 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Alpine Strawberries to ensure they mature before fall.

Custer County, MT (Zone 4b) Short season
136 days
Last Spring Frost May 14
136 growing days
First Fall Frost September 27
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Custer County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 7 🍅 Harvest: Sep 6 – Nov 1
Recommended (50%) ✗ May not fit
Transplant: Jun 11 🍅 Harvest: Sep 10 – Nov 5
Safe Start (90%) ✗ May not fit
Transplant: Jun 22 🍅 Harvest: Sep 21 – Nov 16

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 Custer County

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

Soil pH

Your soil pH (6.5–8.1) is more alkaline than Alpine Strawberries prefers (5.5–6.8). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Alpine Strawberries.

How to Plant Alpine Strawberries

12"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 376 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Alpine Strawberries

Alpine 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 Alpine Strawberries Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 4.3" 2.6" 1.7" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.9" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Alpine 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.

Alpine Strawberries needs ~1,350 GDD — county provides 1,360 GDD Good fit

Alpine Strawberries Planting Timeline — Custer County, MT

Alpine Strawberries Planting Calendar

Activity When Date Range
Transplant Outdoors June 11 Jun 11 – Jun 25
Harvest September 10 Sep 10 – Nov 5

· 12" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–180 days

🧪 Soil pH

Needs 5.5–6.8 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

136 days in Custer County

Growing Tips for Alpine Strawberries in Custer County

Direct sow Alpine Strawberries outdoors after May 14 in Custer County when soil has warmed and frost danger has passed.

Your 136.0-day growing season in Custer County is tight for Alpine Strawberries (90.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

Custer County receives only 24" of rain annually. Alpine Strawberries needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 8-10 weeks before transplanting. Unlike regular strawberries, alpines do not spread by runners. Harvest tiny, intensely aromatic berries frequently. Grow well in partial shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Alpine Strawberries in Custer County, MT?

Custer County is in Zone 4b with an average last frost of May 14. Plan your Alpine Strawberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Custer County, MT?

Custer County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 27.

🌱

Your Custer County Garden Planner — Free

A 24-page printable planner built for Custer County (Zone 4b). 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 Custer 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.