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When to Plant Soybeans in Rapides Parish, LA

Rapides Parish, Louisiana Zone 9a May

Your May planting checklist for Rapides Parish, Louisiana

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

Avg. last frost March 5
Avg. first frost November 16
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
Looking ahead to 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.

Rapides Parish, Louisiana is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 16, giving you a growing season of approximately 256 days.

At an elevation of 388 feet, Rapides Parish receives approximately 54.4 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Soybeans during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.

Rapides Parish, LA (Zone 9a) Long season
256 days
Last Spring Frost March 5
256 growing days
First Fall Frost November 16

Rapides Parish Soil Profile

Soil Type

Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (122 days to spare)
Transplant: Feb 22 🍅 Harvest: May 17 – Jul 12
Recommended (50%) ✓ Fits season (116 days to spare)
Transplant: Mar 5 🍅 Harvest: May 28 – Jul 23
Safe Start (90%) ✓ Fits season (112 days to spare)
Transplant: Apr 6 🍅 Harvest: Jun 29 – Aug 24

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 Rapides Parish

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

Soil pH

Your soil pH (5.9–7.2) overlaps with Soybeans's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Rapides Parish is excellent for Soybeans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Soybeans.

How to Plant Soybeans

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

Succession Planting Soybeans

3
successive plantings in your 256-day season

Sow every 9.1 weeks. Last sowing by Jul 19 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 245 gal / 100 sq ft

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 4.5" 0" ❄️ Dormant
Feb 4.9" 0" ❄️ Dormant
Mar 4.3" 4.9" 0" ✅ Rainfall sufficient
Apr 4.3" 4.5" 0" ✅ Rainfall sufficient
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 5.5" 0" ✅ Rainfall sufficient
Aug 4.3" 5.3" 0" ✅ Rainfall sufficient
Sep 4.3" 4.7" 0" ✅ Rainfall sufficient
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 4.3" 3.9" 0.4" 💧 Light watering
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Rapides 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 ~1,825 GDD — county provides 4,672 GDD Excellent fit

Soybeans Planting Timeline — Rapides Parish, LA

Soybeans Planting Calendar

Activity When Date Range
Direct Sow March 12 Mar 12 – Apr 2
Harvest June 4 Jun 4 – Jul 30

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

256 days in Rapides Parish

Growing Tips for Soybeans in Rapides Parish

Direct sow Soybeans outdoors after March 05 in Rapides Parish when soil has warmed and frost danger has passed.

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 Rapides Parish, LA?

Rapides Parish is in Zone 9a with an average last frost of March 5. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rapides Parish, LA?

Rapides Parish, Louisiana is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 16.

🌱

Your Rapides Parish Garden Planner — Free

A 24-page printable planner built for Rapides 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 Rapides 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.