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When to Plant Radish in St. James Parish, LA

St. James Parish, Louisiana Zone 9a May

Your May planting checklist for St. James Parish, Louisiana

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in St. James Parish, Louisiana.

Avg. last frost February 13
Avg. first frost December 6
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs

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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. James Parish, Louisiana is in USDA Zone 9a. The average last spring frost is February 13 and the first fall frost is December 6, giving you a growing season of approximately 296 days.

At an elevation of 471 feet, St. James Parish receives approximately 52 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°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. James Parish, LA (Zone 9a) Year-round
296 days
Last Spring Frost February 13
296 growing days
First Fall Frost December 6

St. James Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (257 days to spare)
Transplant: Jan 25 🍅 Harvest: Feb 22 – Mar 15
Recommended (50%) ✓ Fits season (247 days to spare)
Transplant: Feb 13 🍅 Harvest: Mar 13 – Apr 3
Safe Start (90%) ✓ Fits season (237 days to spare)
Transplant: Mar 9 🍅 Harvest: Apr 6 – Apr 27

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. James Parish

How your county's soil matches Radish's growing requirements.

Soil pH

Your soil pH (5.0–6.2) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. James Parish 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 low (2.0%). Add 2-3 inches of compost before planting Radish.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Radish

17
successive plantings in your 296-day season

Sow every 2.4 weeks. Last sowing by Nov 01 to harvest before frost.

For a dedicated fall crop, sow by Oct 11.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 4.2" 0" ❄️ Dormant
Feb 2.2" 4.4" 0" ✅ Rainfall sufficient
Mar 2.2" 4.9" 0" ✅ Rainfall sufficient
Apr 2.2" 3.4" 0" ✅ Rainfall sufficient
May 2.2" 4.6" 0" ✅ Rainfall sufficient
Jun 2.2" 4.9" 0" ✅ Rainfall sufficient
Jul 2.2" 5.4" 0" ✅ Rainfall sufficient
Aug 2.2" 5.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.9" 0" ✅ Rainfall sufficient
Nov 2.2" 4.2" 0" ✅ Rainfall sufficient
Dec 2.2" 3.8" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in St. James 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 needs ~648 GDD — county provides 6,756 GDD Excellent fit

Radish Planting Timeline — St. James Parish, LA

Radish Planting Calendar

Activity When Date Range
Direct Sow January 23 Jan 23 – Feb 13
Harvest February 20 Feb 20 – Mar 13
Fall Sowing October 11 Oct 11 – Oct 25

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

MonthActivities
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 9a

📆 Growing Season

296 days in St. James Parish

Growing Tips for Radish in St. James Parish

Direct sow Radish outdoors after February 13 in St. James Parish when soil has warmed and frost danger has passed.

Sandy soil in St. James 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. James Parish reach 97°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 297.0-day season in St. James 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

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in St. James Parish, LA?

St. James Parish is in Zone 9a with an average last frost of February 13. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. James Parish, LA?

St. James Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is February 13 and first fall frost is December 6.

🌱

Your St. James Parish Garden Planner — Free

A 24-page printable planner built for St. James Parish (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for St. James Parish, LA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.