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When to Plant Sweet Potatoes in Lafourche Parish, LA

Lafourche Parish, Louisiana Zone 9b May

May in the garden — Lafourche Parish, Louisiana

Your garden in Lafourche Parish, Louisiana is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost January 27
Avg. first frost December 18
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. It's harvest week for sweet potatoes

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Looking ahead to June
  • First harvests: sweet potatoes

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Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.

Lafourche Parish, Louisiana is in USDA Zone 9b. The average last spring frost is January 27 and the first fall frost is December 18, giving you a growing season of approximately 325 days.

At an elevation of 306 feet, Lafourche Parish receives approximately 54 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Sweet Potatoes may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sweet Potatoes will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Potatoes root diseases.

Lafourche Parish, LA (Zone 9b) Year-round
325 days
Last Spring Frost January 27
325 growing days
First Fall Frost December 18

Lafourche 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 (175 days to spare)
Start indoors: Dec 9 Transplant: Jan 27 🍅 Harvest: Apr 28 – Jun 16
Recommended (50%) ✓ Fits season (178 days to spare)
Start indoors: Dec 16 Transplant: Feb 3 🍅 Harvest: May 5 – Jun 23
Safe Start (90%) ✓ Fits season (149 days to spare)
Start indoors: Jan 21 Transplant: Mar 11 🍅 Harvest: Jun 10 – Jul 29

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 Lafourche Parish

How your county's soil matches Sweet Potatoes's growing requirements.

Soil pH

Your soil pH (5.0–6.2) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.

Soil Texture

Sandy soil in Lafourche Parish warms quickly in spring but drains fast. Sweet Potatoes will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Sweet Potatoes.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Sweet Potatoes.

How to Plant Sweet Potatoes

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
Watering frequency Only during dry spells
Season total 12 gal / 100 sq ft

Monthly Watering Guide for Sweet Potatoes

Sweet Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Sweet Potatoes Needs Rainfall You Supplement Action
Jan 4.3" 4.3" 0" ✅ Rainfall sufficient
Feb 4.3" 4.5" 0" ✅ Rainfall sufficient
Mar 4.3" 5.2" 0" ✅ Rainfall sufficient
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 4.8" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 5.3" 0" ✅ Rainfall sufficient
Aug 4.3" 5.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4.3" 0" ✅ Rainfall sufficient
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 4.3" 3.5" 0.8" 💧 Light watering
Dec 4.3" 3.6" 0.7" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Lafourche Parish). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sweet Potatoes 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.

Sweet Potatoes needs ~2,389 GDD — county provides 7,416 GDD Excellent fit

Sweet Potatoes Planting Timeline — Lafourche Parish, LA

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors December 16 Dec 16 – Dec 30
Transplant Outdoors February 3 Feb 3 – Feb 17
Direct Sow January 27 Jan 27 – Feb 17
Harvest May 5 May 5 – Jun 23

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Direct Sow
February Transplant Outdoors Direct Sow
March
April
May Harvest
June Harvest
July
August
September
October
November
December Start Indoors

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

325 days in Lafourche Parish

Growing Tips for Sweet Potatoes in Lafourche Parish

Direct sow Sweet Potatoes outdoors after January 27 in Lafourche Parish when soil has warmed and frost danger has passed.

Sandy soil in Lafourche Parish dries quickly — mulch Sweet Potatoes with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 97°F in Lafourche Parish, provide afternoon shade for Sweet Potatoes and water deeply in the morning.

General growing tips

Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.

Companion Planting

Good Companions

Avoid Planting Near

  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in Lafourche Parish, LA?

Lafourche Parish is in Zone 9b with an average last frost of January 27. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lafourche Parish, LA?

Lafourche Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is January 27 and first fall frost is December 18.

🌱

Your Lafourche Parish Garden Planner — Free

A 24-page printable planner built for Lafourche 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.

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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 Lafourche 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.