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When to Plant Alpine Strawberries in Mariposa County, CA

Mariposa County, California Zone 9b May

Top priorities for Mariposa County, California gardeners in May

Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 18
Avg. first frost November 9
Soil temp (4") 68°F
Watering Critical
Pest pressure Moderate
Daylight 14 hrs
  1. Harden off and plant alpine strawberries

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

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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.

Mariposa County, California is in USDA Zone 9b. The average last spring frost is April 18 and the first fall frost is November 9, giving you a growing season of approximately 205 days.

At an elevation of 192 feet, Mariposa County receives approximately 19.2 inches of rainfall annually with predominantly loam soil. Summer highs average 91°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.

Mariposa County, CA (Zone 9b) Long season
205 days
Last Spring Frost April 18
205 growing days
First Fall Frost November 9

Mariposa County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Transplant: Apr 7 🍅 Harvest: Jul 7 – Oct 20
Recommended (50%) ✗ May not fit
Transplant: May 2 🍅 Harvest: Aug 1 – Nov 14
Safe Start (90%) ✗ May not fit
Transplant: Jun 1 🍅 Harvest: Aug 31 – Dec 14

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 Mariposa County

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

Soil pH

Your soil pH (6.5–7.5) 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 Mariposa County is excellent for Alpine Strawberries — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.8%). 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
0.4″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,328 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 3.7" 0" ❄️ Dormant
Feb 4.3" 0" ❄️ Dormant
Mar 3.2" 0" ❄️ Dormant
Apr 4.3" 1.6" 2.7" 🚿 Regular watering
May 4.3" 0.5" 3.8" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.2" 4.1" 🚿 Regular watering
Oct 4.3" 0.9" 3.4" 🚿 Regular watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Mariposa 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 ~2,464 GDD — county provides 3,741 GDD Excellent fit

Alpine Strawberries Planting Timeline — Mariposa County, CA

Alpine Strawberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 2 May 2 – May 16
Harvest August 1 Aug 1 – Nov 14

· 12" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

90–180 days

🧪 Soil pH

Needs 5.5–6.8 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

205 days in Mariposa County

Growing Tips for Alpine Strawberries in Mariposa County

Direct sow Alpine Strawberries outdoors after April 18 in Mariposa County when soil has warmed and frost danger has passed.

Mariposa County receives only 19" 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 Mariposa County, CA?

Mariposa County is in Zone 9b with an average last frost of April 18. Plan your Alpine Strawberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mariposa County, CA?

Mariposa County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 18 and first fall frost is November 9.

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Your Mariposa County Garden Planner — Free

A 24-page printable planner built for Mariposa County (Zone 9b). 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 Mariposa County, CA. 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.