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When to Plant Corn in Zapata County, TX

Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

Zapata County, Texas is in USDA Zone 9a. The average last spring frost is February 3 and the first fall frost is December 14, giving you a growing season of approximately 314 days.

At an elevation of 3,340 feet, Zapata County receives approximately 60.6 inches of rainfall annually with predominantly loam soil. Summer highs average 103ยฐF, so Corn may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Corn root diseases.

Zapata County, TX (Zone 9a) Year-round
314 days
Last Spring Frost February 3
314 growing days
First Fall Frost December 14

Zapata County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (204 days to spare)
Transplant: Jan 17 🍅 Harvest: Mar 21 – May 16
Recommended (50%) ✓ Fits season (195 days to spare)
Transplant: Feb 3 🍅 Harvest: Apr 7 – Jun 2
Safe Start (90%) ✓ Fits season (181 days to spare)
Transplant: Feb 27 🍅 Harvest: May 1 – Jun 26

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 Zapata County

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

Soil pH

Your soil pH (6.2โ€“7.6) overlaps with Corn's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Corn.

How to Plant Corn

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

Succession Planting Corn

6
successive plantings in your 314-day season

Sow every 6.9 weeks. Last sowing by Sep 05 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,940 gal / 100 sq ft

Monthly Watering Guide for Corn

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 Corn Needs Rainfall You Supplement Action
Jan โ€” 1.3" 0" โ„๏ธ Dormant
Feb 6.5" 2.3" 4.2" ๐Ÿšฟ Regular watering
Mar 6.5" 4.1" 2.4" ๐Ÿ’ง Light watering
Apr 6.5" 6.3" 0.2" ๐Ÿ’ง Light watering
May 6.5" 7.6" 0" โœ… Rainfall sufficient
Jun 6.5" 10.1" 0" โœ… Rainfall sufficient
Jul 6.5" 8.6" 0" โœ… Rainfall sufficient
Aug 6.5" 7.4" 0" โœ… Rainfall sufficient
Sep 6.5" 6.1" 0.4" ๐Ÿ’ง Light watering
Oct 6.5" 3.3" 3.2" ๐Ÿ’ง Light watering
Nov 6.5" 2" 4.5" ๐Ÿšฟ Regular watering
Dec 6.5" 1.3" 5.2" ๐Ÿšฟ Regular watering

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

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.

Corn needs ~2,180 GDD — county provides 8,583 GDD Excellent fit

Corn Planting Timeline โ€” Zapata County, TX

Corn Planting Calendar

Activity When Date Range
Direct Sow February 10 Feb 10 โ€“ Mar 3
Harvest April 14 Apr 14 โ€“ Jun 9

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 Harvest
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 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

314 days in Zapata County

Growing Tips for Corn in Zapata County

Direct sow Corn outdoors after February 03 in Zapata County when soil has warmed and frost danger has passed.

With summer highs reaching 103ยฐF in Zapata County, provide afternoon shade for Corn and water deeply in the morning.

Common pests for 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 rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Recommended Corn Varieties for Zapata County

Heat-tolerant varieties that silk well in high temps

Silver Queen (92d) Incredible (85d)

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Zapata County, TX?

Zapata County is in Zone 9a with an average last frost of February 3. Plan your Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Zapata County, TX?

Zapata County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 3 and first fall frost is December 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Zapata 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 Zapata County, TX. Local conditions may vary. Last updated: April 2026.