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When to Plant Radish in DeWitt County, TX

DeWitt County, Texas Zone 9a May

What to do in May

A quick May briefing for DeWitt County, Texas gardeners — what's urgent, what's next, and what can wait.

Avg. last frost March 2
Avg. first frost November 26
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 13.5 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.

DeWitt County, Texas is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 26, giving you a growing season of approximately 269 days.

At an elevation of 1,649 feet, DeWitt County receives approximately 62.1 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Radish during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.

DeWitt County, TX (Zone 9a) Long season
269 days
Last Spring Frost March 2
269 growing days
First Fall Frost November 26

DeWitt County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (221 days to spare)
Transplant: Feb 18 🍅 Harvest: Mar 18 – Apr 8
Recommended (50%) ✓ Fits season (220 days to spare)
Transplant: Mar 2 🍅 Harvest: Mar 30 – Apr 20
Safe Start (90%) ✓ Fits season (214 days to spare)
Transplant: Mar 25 🍅 Harvest: Apr 22 – May 13

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 DeWitt County

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

Soil pH

Your soil pH (6.8–7.8) is more alkaline than Radish prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Radish.

Organic Matter

Organic matter is low (1.9%). 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

15
successive plantings in your 269-day season

Sow every 2.4 weeks. Last sowing by Oct 22 to harvest before frost.

For a dedicated fall crop, sow by Oct 01.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/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 1.8" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 2.2" 4" 0" ✅ Rainfall sufficient
Apr 2.2" 5.9" 0" ✅ Rainfall sufficient
May 2.2" 9.1" 0" ✅ Rainfall sufficient
Jun 2.2" 11.3" 0" ✅ Rainfall sufficient
Jul 2.2" 6.9" 0" ✅ Rainfall sufficient
Aug 2.2" 7.9" 0" ✅ Rainfall sufficient
Sep 2.2" 5.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.7" 0" ✅ Rainfall sufficient
Nov 2.2" 2.3" 0" ✅ Rainfall sufficient
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in DeWitt 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 ~520 GDD — county provides 4,909 GDD Excellent fit

Radish Planting Timeline — DeWitt County, TX

Radish Planting Calendar

Activity When Date Range
Direct Sow February 9 Feb 9 – Mar 2
Harvest March 9 Mar 9 – Mar 30
Fall Sowing October 1 Oct 1 – Oct 15

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

Month-by-Month Timeline

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

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_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

269 days in DeWitt County

Growing Tips for Radish in DeWitt County

Direct sow Radish outdoors after March 02 in DeWitt County when soil has warmed and frost danger has passed.

Summer highs in DeWitt County reach 91°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 269.0-day season in DeWitt 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 62" of annual rainfall in DeWitt 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 DeWitt County, TX?

DeWitt County is in Zone 9a with an average last frost of March 2. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is DeWitt County, TX?

DeWitt County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 26.

🌱

Your DeWitt County Garden Planner — Free

A 24-page printable planner built for DeWitt 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 DeWitt County, TX. 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.