When to Plant Soybeans in San Augustine 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.
San Augustine County, Texas is in USDA Zone 8b. The average last spring frost is March 5 and the first fall frost is November 16, giving you a growing season of approximately 256 days.
At an elevation of 146 feet, San Augustine County receives approximately 62.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°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.
San Augustine County Soil Profile
Soil Type
Sandy Loam
Soil pH
5.4-6.6
Drainage
Well Drained
Plant Planting Risk Windows
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 San Augustine County
How your county's soil matches Soybeans's growing requirements.
Soil pH
Your soil pH (5.4–6.6) overlaps with Soybeans's range (6.0–7.0), though not a perfect match.
Soil Texture
Sandy soil in San Augustine 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 (1.8%). Add 2-3 inches of compost before planting Soybeans.
How to Plant Soybeans
Succession Planting Soybeans
Sow every 9.1 weeks. Last sowing by Jul 19 to harvest before frost.
Plant Water Budget
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 6.2" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.2" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 10.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 8.7" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 8.2" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.8" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Nov | 4.3" | 2.3" | 2" | 💧 Light watering |
| Dec | — | 1.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in San Augustine 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 Planting Timeline — San Augustine County, TX
Soybeans Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 12 | Mar 12 – Apr 2 |
| Harvest | June 4 | Jun 4 – Jul 30 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 8b
📆 Growing Season
256 days in San Augustine County
Growing Tips for Soybeans in San Augustine County
Direct sow Soybeans outdoors after March 05 in San Augustine County when soil has warmed and frost danger has passed.
Sandy soil in San Augustine 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 96°F in San Augustine 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
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Check more plant combinations with our Companion Planting Checker →
Soybeans in Other Locations
Frequently Asked Questions
When should I plant Soybeans in San Augustine County, TX?
San Augustine County is in Zone 8b with an average last frost of March 5. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Augustine County, TX?
San Augustine County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 5 and first fall frost is November 16.
Plan Your Garden with Confidence
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