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When to Plant Sweet Corn in Willacy 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.

Willacy County, Texas is in USDA Zone 9b. The average last spring frost is February 4 and the first fall frost is December 22, giving you a growing season of approximately 321 days.

At an elevation of 1,085 feet, Willacy County receives approximately 65.9 inches of rainfall annually with predominantly loam soil. Summer highs average 102ยฐF, 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.

Willacy County, TX (Zone 9b) Year-round
321 days
Last Spring Frost February 4
321 growing days
First Fall Frost December 22

Willacy County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (228 days to spare)
Transplant: Jan 17 🍅 Harvest: Mar 21 – May 2
Recommended (50%) ✓ Fits season (216 days to spare)
Transplant: Feb 4 🍅 Harvest: Apr 8 – May 20
Safe Start (90%) ✓ Fits season (193 days to spare)
Transplant: Mar 4 🍅 Harvest: May 6 – Jun 17

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 Willacy County

How your county's soil matches Sweet Corn's growing requirements.

Soil pH

Your soil pH (6.5โ€“7.3) overlaps with Sweet Corn's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Willacy County is excellent for Sweet Corn โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Sweet Corn.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Sweet Corn.

How to Plant Sweet Corn

1"
Planting Depth
12"
Between Plants
36"
Between Rows

Succession Planting Sweet Corn

6
successive plantings in your 321-day season

Sow every 6.9 weeks. Last sowing by Sep 23 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 3,750 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Sweet Corn

Sweet Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Sweet Corn Needs Rainfall You Supplement Action
Jan โ€” 1.7" 0" โ„๏ธ Dormant
Feb 6.5" 2.3" 4.2" ๐Ÿšฟ Regular watering
Mar 6.5" 4.4" 2.1" ๐Ÿ’ง Light watering
Apr 6.5" 6.4" 0.1" ๐Ÿ’ง Light watering
May 6.5" 9.5" 0" โœ… Rainfall sufficient
Jun 6.5" 9.7" 0" โœ… Rainfall sufficient
Jul 6.5" 9" 0" โœ… Rainfall sufficient
Aug 6.5" 8.5" 0" โœ… Rainfall sufficient
Sep 6.5" 6.3" 0.2" ๐Ÿ’ง Light watering
Oct 6.5" 3.8" 2.7" ๐Ÿ’ง Light watering
Nov 6.5" 2.6" 3.9" ๐Ÿšฟ Regular watering
Dec 6.5" 1.8" 4.7" ๐Ÿšฟ Regular watering

Water needs are for active growing months only (Febโ€“Dec in Willacy County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Sweet Corn 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.

Sweet Corn needs ~1,988 GDD — county provides 8,533 GDD Excellent fit

Sweet Corn Planting Timeline โ€” Willacy County, TX

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow February 11 Feb 11 โ€“ Mar 4
Harvest April 15 Apr 15 โ€“ May 27

Plant 1" deep ยท 12" apart ยท Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.5"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 9b

๐Ÿ“† Growing Season

321 days in Willacy County

Growing Tips for Sweet Corn in Willacy County

Direct sow Sweet Corn outdoors after February 04 in Willacy County when soil has warmed and frost danger has passed.

With summer highs reaching 102ยฐF in Willacy County, provide afternoon shade for Sweet Corn and water deeply in the morning.

Common pests for Sweet Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.

General growing tips

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 Willacy County, TX?

Willacy County is in Zone 9b with an average last frost of February 4. Plan your Sweet Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Willacy County, TX?

Willacy County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 4 and first fall frost is December 22.

๐ŸŒฑ

Plan Your Garden with Confidence

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