When to Plant Radish in St. Charles Parish, LA
Top priorities for St. Charles Parish, Louisiana 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.
St. Charles Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 20 and the first fall frost is December 1, giving you a growing season of approximately 284 days.
At an elevation of 154 feet, St. Charles Parish receives approximately 54.3 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103°F, so Radish may need afternoon shade and extra watering during peak heat. 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.
St. Charles Parish Soil Profile
Soil Type
Sandy Loam
Soil pH
4.9-6.3
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 St. Charles Parish
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (4.9–6.3) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in St. Charles Parish warms quickly in spring but drains fast. Radish will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Radish.
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
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 | — | 4.3" | 0" | ❄️ Dormant |
| Feb | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 4.9" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 5.9" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| Dec | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Feb–Dec in St. Charles Parish). 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 — St. Charles Parish, LA
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | January 30 | Jan 30 – Feb 20 |
| Harvest | February 27 | Feb 27 – Mar 20 |
| 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: too_acidic
🗺️ USDA Zone
Zone 9b
📆 Growing Season
284 days in St. Charles Parish
Growing Tips for Radish in St. Charles Parish
Direct sow Radish outdoors after February 20 in St. Charles Parish when soil has warmed and frost danger has passed.
Sandy soil in St. Charles Parish 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 St. Charles Parish reach 103°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 285.0-day season in St. Charles Parish 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 St. Charles Parish, LA?
St. Charles Parish is in Zone 9b with an average last frost of February 20. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Charles Parish, LA?
St. Charles Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 20 and first fall frost is December 1.
Your St. Charles Parish Garden Planner — Free
A 24-page printable planner built for St. Charles Parish (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.