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When to Plant Radish in Blanco County, TX

Blanco County, Texas Zone 8b May

Top priorities for Blanco County, Texas gardeners in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 8
Avg. first frost November 21
Soil temp (4") 61°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.

Blanco County, Texas is in USDA Zone 8b. The average last spring frost is March 8 and the first fall frost is November 21, giving you a growing season of approximately 258 days.

At an elevation of 4,826 feet, Blanco County receives approximately 61.5 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Radish during the growing season. Clay soil retains moisture well for Radish, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.

Blanco County, TX (Zone 8b) Long season
258 days
Last Spring Frost March 8
258 growing days
First Fall Frost November 21

Blanco County Soil Profile

Soil Type

Clay

Soil pH

7.1-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (207 days to spare)
Transplant: Mar 1 🍅 Harvest: Mar 29 – Apr 19
Recommended (50%) ✓ Fits season (209 days to spare)
Transplant: Mar 8 🍅 Harvest: Apr 5 – Apr 26
Safe Start (90%) ✓ Fits season (198 days to spare)
Transplant: Apr 7 🍅 Harvest: May 5 – May 26

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 Blanco County

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

Soil pH

Your soil pH (7.1–7.7) is more alkaline than Radish prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Your soil has 36% clay, which can cause forked or stunted roots for Radish. Use raised beds with loose, sandy mix for best results.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Radish.

How to Plant Radish

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Radish

14
successive plantings in your 258-day season

Sow every 2.4 weeks. Last sowing by Oct 17 to harvest before frost.

For a dedicated fall crop, sow by Sep 12.

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

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 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.2" 4.3" 0" ✅ Rainfall sufficient
Apr 2.2" 5.8" 0" ✅ Rainfall sufficient
May 2.2" 10.3" 0" ✅ Rainfall sufficient
Jun 2.2" 9.9" 0" ✅ Rainfall sufficient
Jul 2.2" 7.7" 0" ✅ Rainfall sufficient
Aug 2.2" 6.7" 0" ✅ Rainfall sufficient
Sep 2.2" 6.4" 0" ✅ Rainfall sufficient
Oct 2.2" 3.4" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Blanco 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 ~499 GDD — county provides 4,515 GDD Excellent fit

Radish Planting Timeline — Blanco County, TX

Radish Planting Calendar

Activity When Date Range
Direct Sow February 22 Feb 22 – Mar 15
Harvest March 22 Mar 22 – Apr 12
Fall Sowing September 12 Sep 12 – Sep 26

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

Month-by-Month Timeline

MonthActivities
January
February Direct Sow
March Direct Sow Harvest
April Harvest
May
June
July
August
September Fall Sowing
October
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 8b

📆 Growing Season

258 days in Blanco County

Growing Tips for Radish in Blanco County

Direct sow Radish outdoors after March 08 in Blanco County when soil has warmed and frost danger has passed.

With Blanco County's clay soil (36% clay), work in 3-4 inches of compost before planting Radish. Avoid tilling when soil is wet to prevent compaction.

Your generous 258.0-day season in Blanco 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 Blanco 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 Blanco County, TX?

Blanco County is in Zone 8b with an average last frost of March 8. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is Blanco County, TX?

Blanco County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 8 and first fall frost is November 21.

🌱

Your Blanco County Garden Planner — Free

A 24-page printable planner built for Blanco County (Zone 8b). 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 Blanco 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.