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When to Plant Radish in Martin County, FL

Martin County, Florida Zone 10b May

This month in Martin County, Florida

Here's what deserves your attention in Martin County, Florida this month. Everything below is tailored to Zone 10b and timed around your local frost dates.

Avg. last frost January 25
Avg. first frost December 13
Soil temp (4") 80°F
Watering Moderate
Pest pressure High
Daylight 13.3 hrs

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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.

Martin County, Florida is in USDA Zone 10b. The average last spring frost is January 25 and the first fall frost is December 13, giving you a growing season of approximately 322 days.

At an elevation of 80 feet, Martin County receives approximately 56.3 inches of rainfall annually with predominantly sand soil. Summer highs average 88°F, providing good warmth for Radish during the growing season. Sandy soil warms quickly in spring — great for early planting — but Radish will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.

Martin County, FL (Zone 10b) Year-round
322 days
Last Spring Frost January 25
322 growing days
First Fall Frost December 13
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Martin County Soil Profile

Soil Type

Sand

Soil pH

5.1-5.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (279 days to spare)
Transplant: Jan 15 🍅 Harvest: Feb 12 – Mar 5
Recommended (50%) ✓ Fits season (273 days to spare)
Transplant: Jan 25 🍅 Harvest: Feb 22 – Mar 15
Safe Start (90%) ✓ Fits season (260 days to spare)
Transplant: Feb 17 🍅 Harvest: Mar 17 – Apr 7

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 Martin County

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

Soil pH

Your soil pH (5.1–5.7) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Martin County warms quickly in spring but drains fast. Radish will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Radish.

Organic Matter

Organic matter is low (1.5%). Add 2-3 inches of compost before planting 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

18
successive plantings in your 322-day season

Sow every 2.4 weeks. Last sowing by Nov 08 to harvest before frost.

For a dedicated fall crop, sow by Oct 18.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 2.2" 2.8" 0" ✅ Rainfall sufficient
Feb 2.2" 3.1" 0" ✅ Rainfall sufficient
Mar 2.2" 3" 0" ✅ Rainfall sufficient
Apr 2.2" 2.3" 0" ✅ Rainfall sufficient
May 2.2" 3.4" 0" ✅ Rainfall sufficient
Jun 2.2" 8.6" 0" ✅ Rainfall sufficient
Jul 2.2" 7.9" 0" ✅ Rainfall sufficient
Aug 2.2" 8.4" 0" ✅ Rainfall sufficient
Sep 2.2" 8.2" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2.2" 0" ✅ Rainfall sufficient
Dec 2.2" 2.1" 0.1" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Martin 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 ~456 GDD — county provides 5,168 GDD Excellent fit

Radish Planting Timeline — Martin County, FL

Radish Planting Calendar

Activity When Date Range
Direct Sow January 4 Jan 4 – Jan 25
Harvest February 1 Feb 1 – Feb 22
Fall Sowing October 18 Oct 18 – Nov 1

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 10b

📆 Growing Season

322 days in Martin County

Growing Tips for Radish in Martin County

Direct sow Radish outdoors after January 25 in Martin County when soil has warmed and frost danger has passed.

Sandy soil in Martin County dries quickly — mulch Radish with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Your generous 323.0-day season in Martin 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.

With 56" of annual rainfall in Martin County, ensure good drainage for Radish — excess moisture can promote root rot and fungal diseases.

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 Martin County, FL?

Martin County is in Zone 10b with an average last frost of January 25. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Martin County, FL?

Martin County, Florida is in USDA Hardiness Zone 10b. The average last spring frost is January 25 and first fall frost is December 13.

🌱

Your Martin County Garden Planner — Free

A 24-page printable planner built for Martin County (Zone 10b). 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 Martin County, FL. 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.