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When to Plant Yard Long Beans in St. Louis City, MO

St. Louis City, Missouri Zone 7a May

This month in St. Louis City, Missouri

We've pulled the most time-sensitive tasks for St. Louis City, Missouri this May and put them front and centre. Tackle them in order.

Avg. last frost April 8
Avg. first frost October 27
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Begin indoor sowing: yard long beans

    Label every cell. You will absolutely forget which is which otherwise.

A few tasks this May that'll pay off in June
  • First harvests: yard long beans

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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. Louis City, Missouri is in USDA Zone 7a. The average last spring frost is April 8 and the first fall frost is October 27, giving you a growing season of approximately 202 days.

At an elevation of 612 feet, St. Louis City receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Yard Long Beans during the growing season.

St. Louis City, MO (Zone 7a) Long season
202 days
Last Spring Frost April 8
202 growing days
First Fall Frost October 27
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St. Louis City Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🍅 Harvest: Jun 9 – Jul 21
Recommended (50%) ✓ Fits season (90 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jun 17 – Jul 29
Safe Start (90%) ✓ Fits season (95 days to spare)
Start indoors: Mar 2 Transplant: May 4 🍅 Harvest: Jun 29 – Aug 10

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. Louis City

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Yard Long Beans's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in St. Louis City is excellent for Yard Long Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.9%). 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

4
successive plantings in your 202-day season

Sow every 6.3 weeks. Last sowing by Aug 08 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 327 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 2" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 3.2" 0" ❄️ Dormant
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 5.2" 0" ✅ Rainfall sufficient
Jun 4.3" 5.9" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in St. Louis City). 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 ~1,232 GDD — county provides 3,686 GDD Excellent fit

Yard Long Beans Planting Timeline — St. Louis City, MO

Yard Long Beans Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 15 Apr 15 – May 6
Harvest June 17 Jun 17 – Jul 29

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7a

📆 Growing Season

202 days in St. Louis City

Growing Tips for Yard Long Beans in St. Louis City

Direct sow Yard Long Beans outdoors after April 08 in St. Louis City when soil has warmed and frost danger has passed.

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. Louis City, MO?

St. Louis City is in Zone 7a with an average last frost of April 8. Plan your Yard Long Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Louis City, MO?

St. Louis City, Missouri is in USDA Hardiness Zone 7a. The average last spring frost is April 8 and first fall frost is October 27.

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Your St. Louis City Garden Planner — Free

A 24-page printable planner built for St. Louis City (Zone 7a). 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. Louis City, MO. 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.