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When to Plant Carrots in Mariposa County, CA

Mariposa County, California Zone 9b May

Your May game plan for Mariposa County, California

Your garden in Mariposa County, California is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 18
Avg. first frost November 9
Soil temp (4") 68°F
Watering Critical
Pest pressure Moderate
Daylight 14 hrs
  1. Bring in the carrots

    If you can't use it all right away, check the food-preservation section of your planner.

June will be here before you know it — start on
  • First harvests: carrots

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Carrots are a popular root vegetable available in orange, purple, white, and yellow varieties. They are rich in beta-carotene and have a sweet, earthy flavor.

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 Carrots during the growing season. With low rainfall, drip irrigation is essential for growing Carrots 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
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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 (122 days to spare)
Transplant: Mar 24 🍅 Harvest: May 26 – Jun 30
Recommended (50%) ✓ Fits season (107 days to spare)
Transplant: Apr 18 🍅 Harvest: Jun 20 – Jul 25
Safe Start (90%) ✓ Fits season (101 days to spare)
Transplant: May 18 🍅 Harvest: Jul 20 – Aug 24

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 Carrots's growing requirements.

Soil pH

Your soil pH (6.5–7.5) is more alkaline than Carrots prefers (6.0–6.8). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Carrots.

How to Plant Carrots

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Carrots

4
successive plantings in your 205-day season

Sow every 6.9 weeks. Last sowing by Aug 21 to harvest before frost.

For a dedicated fall crop, sow by Sep 14.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.4″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 890 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Carrots

Carrots needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Carrots Needs Rainfall You Supplement Action
Jan 3.7" 0" ❄️ Dormant
Feb 4.3" 0" ❄️ Dormant
Mar 3.2" 0" ❄️ Dormant
Apr 3.5" 1.6" 1.9" 🚿 Regular watering
May 3.5" 0.5" 3" 🚿 Regular watering
Jun 3.5" 0.1" 3.4" 🚿 Regular watering
Jul 3.5" 0" 3.5" 🚿 Regular watering
Aug 3.5" 0" 3.5" 🚿 Regular watering
Sep 3.5" 0.2" 3.3" 🚿 Regular watering
Oct 3.5" 0.9" 2.6" 🚿 Regular watering
Nov 3.5" 1.9" 1.6" 💧 Light 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.

Carrots 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.

Carrots needs ~1,278 GDD — county provides 3,741 GDD Excellent fit

Carrots Planting Timeline — Mariposa County, CA

Carrots Planting Calendar

Activity When Date Range
Direct Sow March 28 Mar 28 – Apr 18
Harvest May 30 May 30 – Jul 4
Fall Sowing September 14 Sep 14 – Sep 28

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Direct Sow
April Direct Sow
May Harvest
June Harvest
July Harvest
August
September Fall Sowing
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–6.8 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

205 days in Mariposa County

Growing Tips for Carrots in Mariposa County

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

Common pests for Carrots in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly in loose, stone-free soil for straight roots. Keep soil moist until germination which can take 2-3 weeks. Thin seedlings to 2 inches apart.

Companion Planting

Good Companions

Avoid Planting Near

  • Dill
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Carrots Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Replant roots for 2nd year flowers. Harvest umbels when brown.
Storage Store airtight; viable 3 years at 35°F, under 50% humidity.

Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial — requires two seasons.

Frequently Asked Questions

When should I plant Carrots in Mariposa County, CA?

Mariposa County is in Zone 9b with an average last frost of April 18. Plan your Carrots 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.

🌱

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.