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When to Plant Radish in Madera County, CA

Madera County, California Zone 9a May

May in the garden — Madera County, California

Here's what deserves your attention in Madera County, California this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost April 18
Avg. first frost November 9
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Bring in the radish

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

Madera County, California is in USDA Zone 9a. 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 187 feet, Madera County receives approximately 14.5 inches of rainfall annually with predominantly loam soil. Summer highs average 104°F, so Radish may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Radish successfully. Mulch heavily to conserve soil moisture.

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

Madera County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (171 days to spare)
Transplant: Mar 24 🍅 Harvest: Apr 21 – May 12
Recommended (50%) ✓ Fits season (156 days to spare)
Transplant: Apr 18 🍅 Harvest: May 16 – Jun 6
Safe Start (90%) ✓ Fits season (150 days to spare)
Transplant: May 18 🍅 Harvest: Jun 15 – Jul 6

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 Madera County

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

Soil pH

Your soil pH (6.2–7.8) overlaps with Radish's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Radish.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Radish

11
successive plantings in your 205-day season

Sow every 2.4 weeks. Last sowing by Oct 05 to harvest before frost.

For a dedicated fall crop, sow by Sep 14.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 444 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Radish

Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Radish Needs Rainfall You Supplement Action
Jan 2.6" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.2" 1.3" 0.9" 💧 Light watering
May 2.2" 0.4" 1.8" 🚿 Regular watering
Jun 2.2" 0.1" 2.1" 🚿 Regular watering
Jul 2.2" 0" 2.2" 🚿 Regular watering
Aug 2.2" 0" 2.2" 🚿 Regular watering
Sep 2.2" 0.1" 2.1" 🚿 Regular watering
Oct 2.2" 0.7" 1.5" 🚿 Regular watering
Nov 2.2" 1.4" 0.8" 💧 Light watering
Dec 2.7" 0" ❄️ Dormant

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

Radish 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.

Radish needs ~798 GDD — county provides 5,740 GDD Excellent fit

Radish Planting Timeline — Madera County, CA

Radish Planting Calendar

Activity When Date Range
Direct Sow March 28 Mar 28 – Apr 18
Harvest April 25 Apr 25 – May 16
Fall Sowing September 14 Sep 14 – Sep 28

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

205 days in Madera County

Growing Tips for Radish in Madera County

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

Summer highs in Madera County reach 104°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 205.0-day season in Madera County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.

Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Madera County, CA?

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

What planting zone is Madera County, CA?

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

🌱

Your Madera County Garden Planner — Free

A 24-page printable planner built for Madera County (Zone 9a). 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 Madera 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.