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When to Plant Soybeans in Irion County, TX

Irion County, Texas Zone 8a May

Top priorities for Irion County, Texas gardeners in May

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Avg. last frost April 1
Avg. first frost November 7
Soil temp (4") 68°F
Watering High
Pest pressure Moderate
Daylight 13.6 hrs

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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.

Irion County, Texas is in USDA Zone 8a. The average last spring frost is April 1 and the first fall frost is November 7, giving you a growing season of approximately 220 days.

At an elevation of 1,818 feet, Irion County receives approximately 51.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 100°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.

Irion County, TX (Zone 8a) Long season
220 days
Last Spring Frost April 1
220 growing days
First Fall Frost November 7
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Irion County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.6-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (81 days to spare)
Transplant: Mar 21 🍅 Harvest: Jun 13 – Aug 8
Recommended (50%) ✓ Fits season (80 days to spare)
Transplant: Apr 1 🍅 Harvest: Jun 24 – Aug 19
Safe Start (90%) ✓ Fits season (82 days to spare)
Transplant: Apr 15 🍅 Harvest: Jul 8 – Sep 2

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 Irion County

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

Soil pH

Your soil pH (7.6–8.6) is more alkaline than Soybeans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Irion County 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 low (1.0%). Add 2-3 inches of compost before planting Soybeans.

How to Plant Soybeans

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

Succession Planting Soybeans

3
successive plantings in your 220-day season

Sow every 9.1 weeks. Last sowing by Jul 10 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 44 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 3.8" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.3" 1.8" 2.5" 🚿 Regular watering
May 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 9.5" 0" ✅ Rainfall sufficient
Aug 4.3" 9.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6.8" 0" ✅ Rainfall sufficient
Oct 4.3" 4.5" 0" ✅ Rainfall sufficient
Nov 4.3" 2.8" 1.5" 💧 Light watering
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Irion County). 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 ~2,500 GDD — county provides 5,500 GDD Excellent fit

Soybeans Planting Timeline — Irion County, TX

Soybeans Planting Calendar

Activity When Date Range
Direct Sow April 8 Apr 8 – Apr 29
Harvest July 1 Jul 1 – Aug 26

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May
June
July Harvest
August Harvest
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

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 8a

📆 Growing Season

220 days in Irion County

Growing Tips for Soybeans in Irion County

Direct sow Soybeans outdoors after April 01 in Irion County when soil has warmed and frost danger has passed.

Sandy soil in Irion County 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 100°F in Irion County, 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 Irion County, TX?

Irion County is in Zone 8a with an average last frost of April 1. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Irion County, TX?

Irion County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is April 1 and first fall frost is November 7.

🌱

Your Irion County Garden Planner — Free

A 24-page printable planner built for Irion County (Zone 8a). 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 Irion County, TX. 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.