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When to Plant Soybeans in Plaquemines Parish, LA

Plaquemines Parish, Louisiana Zone 9b May

May in Plaquemines Parish, Louisiana — your action list

A quick May briefing for Plaquemines Parish, Louisiana gardeners — what's urgent, what's next, and what can wait.

Avg. last frost February 6
Avg. first frost December 7
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Harvest soybeans as they ripen

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Get ahead of June
  • First harvests: soybeans

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Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

Plaquemines Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 6 and the first fall frost is December 7, giving you a growing season of approximately 304 days.

At an elevation of 386 feet, Plaquemines Parish receives approximately 50.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 99°F, so Soybeans may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Soybeans will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.

Plaquemines Parish, LA (Zone 9b) Year-round
304 days
Last Spring Frost February 6
304 growing days
First Fall Frost December 7

Plaquemines Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (170 days to spare)
Transplant: Jan 25 🍅 Harvest: Apr 19 – Jun 14
Recommended (50%) ✓ Fits season (164 days to spare)
Transplant: Feb 6 🍅 Harvest: May 1 – Jun 26
Safe Start (90%) ✓ Fits season (149 days to spare)
Transplant: Mar 9 🍅 Harvest: Jun 1 – Jul 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 Plaquemines Parish

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

Soil pH

Your soil pH (4.8–6.0) is more acidic than Soybeans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.0%). Annual compost additions will help Soybeans.

How to Plant Soybeans

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

Succession Planting Soybeans

4
successive plantings in your 304-day season

Sow every 9.1 weeks. Last sowing by Aug 09 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 1,006 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Soybeans

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

Month Soybeans Needs Rainfall You Supplement Action
Jan 3.7" 0" ❄️ Dormant
Feb 4.3" 3.5" 0.8" 💧 Light watering
Mar 4.3" 4.4" 0" ✅ Rainfall sufficient
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 5.9" 0" ✅ Rainfall sufficient
Aug 4.3" 5.2" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 4.3" 3.7" 0.6" 💧 Light watering
Dec 4.3" 4.5" 0" ✅ Rainfall sufficient

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

Soybeans 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.

Soybeans needs ~2,425 GDD — county provides 7,396 GDD Excellent fit

Soybeans Planting Timeline — Plaquemines Parish, LA

Soybeans Planting Calendar

Activity When Date Range
Direct Sow February 13 Feb 13 – Mar 6
Harvest May 8 May 8 – Jul 3

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

304 days in Plaquemines Parish

Growing Tips for Soybeans in Plaquemines Parish

Direct sow Soybeans outdoors after February 06 in Plaquemines Parish when soil has warmed and frost danger has passed.

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

With summer highs reaching 99°F in Plaquemines Parish, provide afternoon shade for Soybeans and water deeply in the morning.

Common pests for Soybeans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Plaquemines Parish, LA?

Plaquemines Parish is in Zone 9b with an average last frost of February 6. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Plaquemines Parish, LA?

Plaquemines Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 6 and first fall frost is December 7.

🌱

Your Plaquemines Parish Garden Planner — Free

A 24-page printable planner built for Plaquemines 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 Plaquemines 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.