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When to Plant Alpine Strawberries in Jefferson County, ID

Jefferson County, Idaho Zone 5a May

Your May gardening checklist

Here's what deserves your attention in Jefferson County, Idaho this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost May 22
Avg. first frost September 21
Soil temp (4") 43°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
Get ahead of June
  • 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.

Jefferson County, Idaho is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 21, giving you a growing season of approximately 122 days.

At an elevation of 5,094 feet, Jefferson County receives approximately 18 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Alpine Strawberries during the growing season. With low rainfall, drip irrigation is essential for growing Alpine Strawberries successfully. Mulch heavily to conserve soil moisture.

Jefferson County, ID (Zone 5a) Short season
122 days
Last Spring Frost May 22
122 growing days
First Fall Frost September 21
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Jefferson County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 30 🍅 Harvest: Aug 29 – Nov 14
Recommended (50%) ✗ May not fit
Transplant: Jun 12 🍅 Harvest: Sep 11 – Nov 27
Safe Start (90%) ✗ May not fit
Transplant: Jul 8 🍅 Harvest: Oct 7 – Dec 23

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 Alpine Strawberries's growing requirements.

Soil pH

Your soil pH (6.3–7.8) 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 Jefferson County is excellent for Alpine Strawberries — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). 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
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 496 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 1.9" 2.4" 🚿 Regular watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.4" 2.9" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Jefferson 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 ~2,059 GDD — county provides 1,860 GDD Tight fit

Alpine Strawberries Planting Timeline — Jefferson County, ID

Alpine Strawberries Planting Calendar

Activity When Date Range
Transplant Outdoors June 12 Jun 12 – Jun 26
Harvest September 11 Sep 11 – Nov 27

· 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 5a

📆 Growing Season

122 days in Jefferson County

Growing Tips for Alpine Strawberries in Jefferson County

Direct sow Alpine Strawberries outdoors after May 22 in Jefferson County when soil has warmed and frost danger has passed.

Your 122.0-day growing season in Jefferson County is tight for Alpine Strawberries (90.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

Jefferson County receives only 18" 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 Jefferson County, ID?

Jefferson County is in Zone 5a with an average last frost of May 22. Plan your Alpine Strawberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, ID?

Jefferson County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 22 and first fall frost is September 21.

🌱

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, ID. 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.