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When to Plant Yard Long Beans in St. Mary Parish, LA

St. Mary Parish, Louisiana Zone 9b May

Your May gardening checklist

Each item below is timed to St. Mary Parish, Louisiana's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost February 14
Avg. first frost December 5
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Pick yard long beans

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

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Yard long beans are a tropical legume that produces slender pods up to 24 inches long. They are a staple in Southeast Asian cooking and thrive in hot weather.

St. Mary Parish, Louisiana is in USDA Zone 9b. The average last spring frost is February 14 and the first fall frost is December 5, giving you a growing season of approximately 294 days.

At an elevation of 252 feet, St. Mary Parish receives approximately 48.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Yard Long Beans may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Yard Long Beans will need more frequent watering and organic matter to retain nutrients.

St. Mary Parish, LA (Zone 9b) Year-round
294 days
Last Spring Frost February 14
294 growing days
First Fall Frost December 5

St. Mary Parish Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (190 days to spare)
Start indoors: Dec 25 Transplant: Feb 12 🍅 Harvest: Apr 9 – May 21
Recommended (50%) ✓ Fits season (189 days to spare)
Start indoors: Jan 3 Transplant: Feb 21 🍅 Harvest: Apr 18 – May 30
Safe Start (90%) ✓ Fits season (179 days to spare)
Start indoors: Jan 28 Transplant: Mar 18 🍅 Harvest: May 13 – Jun 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 St. Mary Parish

How your county's soil matches Yard Long Beans's growing requirements.

Soil pH

Your soil pH (4.8–6.4) is more acidic than Yard Long Beans prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Mary Parish warms quickly in spring but drains fast. Yard Long Beans will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Yard Long Beans.

Organic Matter

Organic matter is moderate (2.0%). Annual compost additions will help Yard Long Beans.

How to Plant Yard Long Beans

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

Succession Planting Yard Long Beans

6
successive plantings in your 294-day season

Sow every 6.3 weeks. Last sowing by Sep 16 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 30 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Yard Long Beans

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

Month Yard Long Beans Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 4.3" 3.4" 0.9" 💧 Light watering
Mar 4.3" 5.1" 0" ✅ Rainfall sufficient
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 5.6" 0" ✅ Rainfall sufficient
Aug 4.3" 5.1" 0" ✅ Rainfall sufficient
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 3.9" 0.4" 💧 Light watering
Dec 4.3" 4.2" 0.1" 💧 Light watering

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

Yard Long Beans 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.

Yard Long Beans needs ~1,434 GDD — county provides 6,268 GDD Excellent fit

Yard Long Beans Planting Timeline — St. Mary Parish, LA

Yard Long Beans Planting Calendar

Activity When Date Range
Start Indoors January 3 Jan 3 – Jan 17
Transplant Outdoors February 21 Feb 21 – Mar 7
Direct Sow February 14 Feb 14 – Mar 7
Harvest April 18 Apr 18 – May 30

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

55–80 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

294 days in St. Mary Parish

Growing Tips for Yard Long Beans in St. Mary Parish

Direct sow Yard Long Beans outdoors after February 14 in St. Mary Parish when soil has warmed and frost danger has passed.

Sandy soil in St. Mary Parish dries quickly — mulch Yard Long Beans with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Common pests for Yard Long Beans 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 is warm. Provide tall poles or trellising as vines can reach 8-10 feet. Harvest when pods are pencil-thick before seeds bulge. Cook quickly for best texture.

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 Yard Long Beans in St. Mary Parish, LA?

St. Mary Parish is in Zone 9b with an average last frost of February 14. Plan your Yard Long Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Mary Parish, LA?

St. Mary Parish, Louisiana is in USDA Hardiness Zone 9b. The average last spring frost is February 14 and first fall frost is December 5.

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Your St. Mary Parish Garden Planner — Free

A 24-page printable planner built for St. Mary 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 St. Mary 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.