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When to Plant Sweet Corn in Duval County, TX

Sweet corn is bred for high sugar content in its kernels, which convert to starch rapidly after harvest. Modern supersweet varieties hold their sweetness longer.

Duval County, Texas is in USDA Zone 9a. The average last spring frost is February 13 and the first fall frost is December 9, giving you a growing season of approximately 299 days.

At an elevation of 4,259 feet, Duval County receives approximately 55.2 inches of rainfall annually with predominantly loam soil. Summer highs average 102Β°F, so Sweet Corn may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Corn root diseases.

Duval County, TX (Zone 9a) Year-round
299 days
Last Spring Frost February 13
299 growing days
First Fall Frost December 9

Duval County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.3

Drainage

Well Drained

Monthly Watering Guide for Sweet Corn

Sweet Corn needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Sweet Corn Needs Rainfall You Supplement Action
Jan β€” 1.6" 0" ❄️ Dormant
Feb 4.3" 1.7" 2.6" 🚿 Regular watering
Mar 4.3" 4" 0.3" πŸ’§ Light watering
Apr 4.3" 5.3" 0" βœ… Rainfall sufficient
May 4.3" 8.7" 0" βœ… Rainfall sufficient
Jun 4.3" 8.4" 0" βœ… Rainfall sufficient
Jul 4.3" 6.8" 0" βœ… Rainfall sufficient
Aug 4.3" 6" 0" βœ… Rainfall sufficient
Sep 4.3" 5.7" 0" βœ… Rainfall sufficient
Oct 4.3" 3.6" 0.7" πŸ’§ Light watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 4.3" 1.6" 2.7" 🚿 Regular watering

Water needs are for active growing months only (Feb–Dec in Duval County). Supplement amounts are based on average rainfall β€” actual needs vary with temperature, soil, and mulching.

Sweet Corn Planting Timeline β€” Duval County, TX

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow February 20 Feb 20 – Mar 13
Harvest April 24 Apr 24 – Jun 5

Plant 1" deep Β· 12" apart Β· Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

β˜€οΈ Sun

Full Sun (6-8+ hours)

πŸ’§ Water

Moderate β€” regular watering

πŸ“… Days to Maturity

60–90 days

πŸ§ͺ Soil pH

Needs 6–7 Β· Your soil: N/A

πŸ—ΊοΈ USDA Zone

Zone 9a

πŸ“† Growing Season

299 days in Duval County

Growing Tips for Duval County

Plant in blocks of at least 4 rows for wind pollination. Direct sow after soil is warm. Isolate supersweet varieties from other corn types to prevent cross-pollination.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Corn in Duval County, TX?

Duval County is in Zone 9a with an average last frost of February 13. Plan your Sweet Corn planting based on this frost date β€” see the calendar above for exact timing.

What planting zone is Duval County, TX?

Duval County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 13 and first fall frost is December 9.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner β€” designed to help Duval County gardeners in Zone 9a 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 Duval County, TX. Local conditions may vary. Last updated: April 2026.