When to Plant Radish in Knox County, TX
Top priorities for Knox 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.
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.
Knox County, Texas is in USDA Zone 8a. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.
At an elevation of 1,847 feet, Knox County receives approximately 51.2 inches of rainfall annually with predominantly loam soil. Summer highs average 93°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.
Knox County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.2
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 Knox County
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (6.4–7.2) overlaps with Radish's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in Knox County is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is low (1.9%). Add 2-3 inches of compost before planting 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 08 to harvest before frost.
For a dedicated fall crop, sow by Sep 03.
Plant Water Budget
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 2.1" | 0" | ❄️ Dormant |
| Mar | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 6.4" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 6.7" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 7.3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 6.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 5.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 5.4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Knox 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 — Knox County, TX
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 10 | Mar 10 – Mar 31 |
| Harvest | April 7 | Apr 7 – Apr 28 |
| Fall Sowing | September 3 | Sep 3 – Sep 17 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| 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: acceptable
🗺️ USDA Zone
Zone 8a
📆 Growing Season
233 days in Knox County
Growing Tips for Radish in Knox County
Direct sow Radish outdoors after March 24 in Knox County when soil has warmed and frost danger has passed.
Summer highs in Knox County reach 93°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 233.0-day season in Knox 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 Knox County, TX?
Knox County is in Zone 8a with an average last frost of March 24. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Knox County, TX?
Knox County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 24 and first fall frost is November 12.
Your Knox County Garden Planner — Free
A 24-page printable planner built for Knox County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.