Blog

When to Plant Soybeans in McMullen County, TX

McMullen County, Texas Zone 9b June

Your June gardening checklist

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 20
Avg. first frost December 1
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Harvest soybeans as they ripen

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

To set up a strong July, finish these tasks
  • First harvests: soybeans

Instant PDF download. No spam, unsubscribe any time.

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.

McMullen County, Texas is in USDA Zone 9b. The average last spring frost is February 20 and the first fall frost is December 1, giving you a growing season of approximately 284 days.

At an elevation of 3,741 feet, McMullen County receives approximately 58 inches of rainfall annually with predominantly loam soil. Summer highs average 103°F, so Soybeans may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.

McMullen County, TX (Zone 9b) Year-round
284 days
Last Spring Frost February 20
284 growing days
First Fall Frost December 1

McMullen County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.2

Drainage

Well Drained

Soybeans Planting Risk Windows

Early Start (70% safe) ✓ Fits season (154 days to spare)
Transplant: Feb 3 🍅 Harvest: Apr 28 – Jun 23
Recommended (50%) ✓ Fits season (144 days to spare)
Transplant: Feb 20 🍅 Harvest: May 15 – Jul 10
Safe Start (90%) ✓ Fits season (137 days to spare)
Transplant: Mar 17 🍅 Harvest: Jun 9 – Aug 4

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 McMullen County

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

Soil pH

Your soil pH (6.8–7.2) overlaps with Soybeans's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in McMullen County 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

4
successive plantings in your 284-day season

Sow every 9.1 weeks. Last sowing by Aug 03 to harvest before frost.

Soybeans 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 442 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 1.6" 0" ❄️ Dormant
Feb 4.3" 2" 2.3" 🚿 Regular watering
Mar 4.3" 3.7" 0.6" 💧 Light watering
Apr 4.3" 6.4" 0" ✅ Rainfall sufficient
May 4.3" 9.4" 0" ✅ Rainfall sufficient
Jun 4.3" 9.8" 0" ✅ Rainfall sufficient
Jul 4.3" 7.3" 0" ✅ Rainfall sufficient
Aug 4.3" 6.5" 0" ✅ Rainfall sufficient
Sep 4.3" 4.6" 0" ✅ Rainfall sufficient
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 1.7" 2.6" 🚿 Regular watering
Dec 4.3" 1.3" 3" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in McMullen 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 ~2,725 GDD — county provides 7,766 GDD Excellent fit

Soybeans Planting Timeline — McMullen County, TX

Soybeans Planting Calendar

Activity When Date Range
Direct Sow February 27 Feb 27 – Mar 20
Harvest May 22 May 22 – Jul 17

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 · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

284 days in McMullen County

Growing Tips for Soybeans in McMullen County

Direct sow Soybeans outdoors after February 20 in McMullen County when soil has warmed and frost danger has passed.

With summer highs reaching 103°F in McMullen 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 McMullen County, TX?

McMullen County is in Zone 9b with an average last frost of February 20. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is McMullen County, TX?

McMullen County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 20 and first fall frost is December 1.

🌱

Your McMullen County Garden Planner — Free

A 22-page printable planner built for McMullen County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for McMullen County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.