When to Plant Radish in Starr 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.
Starr County, Texas is in USDA Zone 9b. The average last spring frost is February 3 and the first fall frost is December 16, giving you a growing season of approximately 316 days.
At an elevation of 2,451 feet, Starr County receives approximately 55.4 inches of rainfall annually with predominantly loam soil. Summer highs average 98°F, so Radish may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.
Starr County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.5
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 Starr County
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (6.8–7.5) is more alkaline than Radish prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Starr County is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.1%). Annual compost additions will help Radish.
How to Plant Radish
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Radish
Sow every 2.4 weeks. Last sowing by Nov 11 to harvest before frost.
For a dedicated fall crop, sow by Oct 21.
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Mar | 2.2" | 3.4" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 8.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 7.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 6.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 1.6" | 0.6" | 💧 Light watering |
| Dec | 2.2" | 1.6" | 0.6" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in Starr 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 — Starr County, TX
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | January 13 | Jan 13 – Feb 3 |
| Harvest | February 10 | Feb 10 – Mar 3 |
| Fall Sowing | October 21 | Oct 21 – Nov 4 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Direct Sow |
| February | Direct Sow Harvest |
| March | Harvest |
| April | — |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | Fall Sowing |
| 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 9b
📆 Growing Season
316 days in Starr County
Growing Tips for Radish in Starr County
Direct sow Radish outdoors after February 03 in Starr County when soil has warmed and frost danger has passed.
Summer highs in Starr County reach 98°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 317.0-day season in Starr 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 55" of annual rainfall in Starr 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
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Check more plant combinations with our Companion Planting Checker →
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Starr County, TX?
Starr County is in Zone 9b with an average last frost of February 3. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Starr County, TX?
Starr County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 3 and first fall frost is December 16.
Plan Your Garden with Confidence
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