When to Plant Radish in Comal County, TX
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.
Comal County, Texas is in USDA Zone 8b. The average last spring frost is March 6 and the first fall frost is November 22, giving you a growing season of approximately 261 days.
At an elevation of 1,346 feet, Comal County receives approximately 58.6 inches of rainfall annually with predominantly clay soil. Summer highs average 91°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.
Comal County Soil Profile
Soil Type
Clay
Soil pH
6.7-7.7
Drainage
Well Drained
Plant Planting Risk Windows
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 Comal County
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (6.7–7.7) is more alkaline than Radish prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
Your soil has 47% clay, which can cause forked or stunted roots for Radish. Use raised beds with loose, sandy mix for best results.
Drainage
Drainage is adequate for Radish.
Organic Matter
Organic matter is moderate (3.3%). Annual compost additions will help Radish.
How to Plant Radish
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Radish
Sow every 2.4 weeks. Last sowing by Oct 18 to harvest before frost.
For a dedicated fall crop, sow by Sep 13.
Plant Water Budget
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 2.1" | 0" | ❄️ Dormant |
| Mar | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 9.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 9.9" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 6.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2" | 0.2" | 💧 Light watering |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Comal 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 Planting Timeline — Comal County, TX
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | February 20 | Feb 20 – Mar 13 |
| Harvest | March 20 | Mar 20 – Apr 10 |
| Fall Sowing | September 13 | Sep 13 – Sep 27 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
261 days in Comal County
Growing Tips for Radish in Comal County
Direct sow Radish outdoors after March 06 in Comal County when soil has warmed and frost danger has passed.
With Comal County's clay soil (47% clay), work in 3-4 inches of compost before planting Radish. Avoid tilling when soil is wet to prevent compaction.
Summer highs in Comal County reach 91°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 261.0-day season in Comal 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
Check more plant combinations with our Companion Planting Checker →
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Comal County, TX?
Comal County is in Zone 8b with an average last frost of March 6. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Comal County, TX?
Comal County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 6 and first fall frost is November 22.
Plan Your Garden with Confidence
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