When to Plant Radish in San Jacinto County, TX
May in San Jacinto County, Texas — your action list
Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.
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.
San Jacinto County, Texas is in USDA Zone 9a. The average last spring frost is February 18 and the first fall frost is December 1, giving you a growing season of approximately 286 days.
At an elevation of 6 feet, San Jacinto County receives approximately 71.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°F, providing good warmth for Radish during the growing season. Sandy soil warms quickly in spring — great for early planting — but Radish will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.
San Jacinto County Soil Profile
Soil Type
Sandy Loam
Soil pH
5.3-6.7
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 San Jacinto County
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (5.3–6.7) overlaps with Radish's range (6.0–7.0), though not a perfect match.
Soil Texture
Sandy soil in San Jacinto County warms quickly in spring but drains fast. Radish will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is moderate (2.2%). 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 Oct 27 to harvest before frost.
For a dedicated fall crop, sow by Oct 06.
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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 8.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 9.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 11.4" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 9.2" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 6.7" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 5.2" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Dec | 2.2" | 1.9" | 0.3" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in San Jacinto 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 — San Jacinto County, TX
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | January 28 | Jan 28 – Feb 18 |
| Harvest | February 25 | Feb 25 – Mar 18 |
| Fall Sowing | October 6 | Oct 6 – Oct 20 |
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 | — |
| 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 9a
📆 Growing Season
286 days in San Jacinto County
Growing Tips for Radish in San Jacinto County
Direct sow Radish outdoors after February 18 in San Jacinto County when soil has warmed and frost danger has passed.
Sandy soil in San Jacinto County dries quickly — mulch Radish with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
Summer highs in San Jacinto County reach 94°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 287.0-day season in San Jacinto 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 San Jacinto County, TX?
San Jacinto County is in Zone 9a with an average last frost of February 18. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Jacinto County, TX?
San Jacinto County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 18 and first fall frost is December 1.
Your San Jacinto County Garden Planner — Free
A 24-page printable planner built for San Jacinto County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.