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When to Plant Soybeans in Tarrant County, TX

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.

Tarrant County, Texas is in USDA Zone 8a. The average last spring frost is March 18 and the first fall frost is November 12, giving you a growing season of approximately 239 days.

At an elevation of 3,487 feet, Tarrant County receives approximately 63.1 inches of rainfall annually with predominantly clay soil. Summer highs average 92ยฐF, providing good warmth for Soybeans during the growing season. Clay soil retains moisture well for Soybeans, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Soybeans root diseases.

Tarrant County, TX (Zone 8a) Long season
239 days
Last Spring Frost March 18
239 growing days
First Fall Frost November 12

Tarrant County Soil Profile

Soil Type

Clay

Soil pH

7.3-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (107 days to spare)
Transplant: Mar 6 🍅 Harvest: May 29 – Jul 24
Recommended (50%) ✓ Fits season (99 days to spare)
Transplant: Mar 18 🍅 Harvest: Jun 10 – Aug 5
Safe Start (90%) ✓ Fits season (96 days to spare)
Transplant: Apr 12 🍅 Harvest: Jul 5 – Aug 30

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 Tarrant County

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

Soil pH

Your soil pH (7.3โ€“8.1) is more alkaline than Soybeans prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (45% clay) in Tarrant County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Organic Matter

Organic matter is moderate (3.1%). 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 239-day season

Sow every 9.1 weeks. Last sowing by Jul 15 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 โ€” 1.8" 0" โ„๏ธ Dormant
Feb โ€” 2.2" 0" โ„๏ธ Dormant
Mar 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Apr 4.3" 7" 0" โœ… Rainfall sufficient
May 4.3" 9.8" 0" โœ… Rainfall sufficient
Jun 4.3" 10.1" 0" โœ… Rainfall sufficient
Jul 4.3" 7.2" 0" โœ… Rainfall sufficient
Aug 4.3" 8.1" 0" โœ… Rainfall sufficient
Sep 4.3" 5.5" 0" โœ… Rainfall sufficient
Oct 4.3" 4.1" 0.2" ๐Ÿ’ง Light watering
Nov 4.3" 2.2" 2.1" ๐Ÿ’ง Light watering
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Tarrant County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,900 GDD — county provides 4,541 GDD Excellent fit

Soybeans Planting Timeline โ€” Tarrant County, TX

Soybeans Planting Calendar

Activity When Date Range
Direct Sow March 25 Mar 25 โ€“ Apr 15
Harvest June 17 Jun 17 โ€“ Aug 12

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

239 days in Tarrant County

Growing Tips for Soybeans in Tarrant County

Direct sow Soybeans outdoors after March 18 in Tarrant County when soil has warmed and frost danger has passed.

With Tarrant County's clay soil (45% clay), work in 3-4 inches of compost before planting Soybeans. Avoid tilling when soil is wet to prevent compaction.

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 Tarrant County, TX?

Tarrant County is in Zone 8a with an average last frost of March 18. Plan your Soybeans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Tarrant County, TX?

Tarrant County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 18 and first fall frost is November 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Tarrant County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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