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When to Plant Radicchio in Castro County, TX

Castro County, Texas Zone 7a June

Your June game plan for Castro County, Texas

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

Avg. last frost April 14
Avg. first frost October 24
Soil temp (4") 68°F
Watering High
Pest pressure High
Daylight 14.3 hrs
  1. Basket week: radicchio

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Before July arrives, get these ready
  • First harvests: radicchio

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Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.

Castro County, Texas is in USDA Zone 7a. The average last spring frost is April 14 and the first fall frost is October 24, giving you a growing season of approximately 193 days.

At an elevation of 3,838 feet, Castro County receives approximately 47.6 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Radicchio may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Radicchio will need more frequent watering and organic matter to retain nutrients.

Castro County, TX (Zone 7a) Moderate season
193 days
Last Spring Frost April 14
193 growing days
First Fall Frost October 24

Castro County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.5-8.1

Drainage

Well Drained

Radicchio Planting Risk Windows

Early Start (70% safe) ✓ Fits season (96 days to spare)
Start indoors: Mar 3 Transplant: Apr 7 🍅 Harvest: Jun 9 – Jul 14
Recommended (50%) ✓ Fits season (95 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 21
Safe Start (90%) ✓ Fits season (96 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: Jul 3 – Aug 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 Castro County

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

Soil pH

Your soil pH (7.5–8.1) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.0%). Add 2-3 inches of compost before planting Radicchio.

How to Plant Radicchio

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

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

Succession Planting Radicchio

3
successive plantings in your 193-day season

Sow every 6.9 weeks. Last sowing by Aug 05 to harvest before frost.

For a dedicated fall crop, sow by Aug 15.

Radicchio Water Budget

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

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

Monthly Watering Guide for Radicchio

Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Radicchio Needs Rainfall You Supplement Action
Jan 3.3" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3" 1.7" 1.3" 💧 Light watering
May 3" 1.2" 1.8" 🚿 Regular watering
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 8" 0" ✅ Rainfall sufficient
Aug 3" 8.9" 0" ✅ Rainfall sufficient
Sep 3" 6.8" 0" ✅ Rainfall sufficient
Oct 3" 4.9" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

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

Radicchio 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.

Radicchio needs ~1,488 GDD — county provides 4,101 GDD Excellent fit

Radicchio Planting Timeline — Castro County, TX

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest June 16 Jun 16 – Jul 21
Fall Sowing August 15 Aug 15 – Aug 29

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

193 days in Castro County

Growing Tips for Radicchio in Castro County

Direct sow Radicchio outdoors after April 14 in Castro County when soil has warmed and frost danger has passed.

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

Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radicchio in Castro County, TX?

Castro County is in Zone 7a with an average last frost of April 14. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Castro County, TX?

Castro County, Texas is in USDA Hardiness Zone 7a. The average last spring frost is April 14 and first fall frost is October 24.

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Your Castro County Garden Planner — Free

A 22-page printable planner built for Castro County (Zone 7a). 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 Castro County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

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