Blog

When to Plant Sweet Corn in Frio 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.

Frio County, Texas is in USDA Zone 8b. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.

At an elevation of 3,892 feet, Frio County receives approximately 51 inches of rainfall annually with predominantly loam soil. Summer highs average 93ยฐF, providing good warmth for Sweet Corn during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Corn root diseases.

Frio County, TX (Zone 8b) Year-round
273 days
Last Spring Frost February 26
273 growing days
First Fall Frost November 26

Frio County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (173 days to spare)
Transplant: Feb 13 🍅 Harvest: Apr 17 – May 29
Recommended (50%) ✓ Fits season (168 days to spare)
Transplant: Feb 26 🍅 Harvest: Apr 30 – Jun 11
Safe Start (90%) ✓ Fits season (161 days to spare)
Transplant: Mar 21 🍅 Harvest: May 23 – Jul 4

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 Frio County

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

Soil pH

Your soil pH (6.4โ€“7.2) overlaps with Sweet Corn's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Frio 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 (2.2%). 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

5
successive plantings in your 273-day season

Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 2,849 gal / 100 sq ft

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€” 1.2" 0" โ„๏ธ Dormant
Feb 6.5" 1.9" 4.6" ๐Ÿšฟ Regular watering
Mar 6.5" 3.6" 2.9" ๐Ÿ’ง Light watering
Apr 6.5" 4.9" 1.6" ๐Ÿ’ง Light watering
May 6.5" 7.5" 0" โœ… Rainfall sufficient
Jun 6.5" 9.4" 0" โœ… Rainfall sufficient
Jul 6.5" 6.3" 0.2" ๐Ÿ’ง Light watering
Aug 6.5" 5.2" 1.3" ๐Ÿ’ง Light watering
Sep 6.5" 4.6" 1.9" ๐Ÿ’ง Light watering
Oct 6.5" 3.4" 3.1" ๐Ÿ’ง Light watering
Nov 6.5" 1.6" 4.9" ๐Ÿšฟ Regular watering
Dec โ€” 1.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Febโ€“Nov in Frio 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 ~1,481 GDD — county provides 5,411 GDD Excellent fit

Sweet Corn Planting Timeline โ€” Frio County, TX

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow March 5 Mar 5 โ€“ Mar 26
Harvest May 7 May 7 โ€“ Jun 18

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Direct Sow
April โ€”
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 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 8b

๐Ÿ“† Growing Season

273 days in Frio County

Growing Tips for Sweet Corn in Frio County

Direct sow Sweet Corn outdoors after February 26 in Frio County when soil has warmed and frost danger has passed.

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 Frio County, TX?

Frio County is in Zone 8b with an average last frost of February 26. Plan your Sweet Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Frio County, TX?

Frio County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is February 26 and first fall frost is November 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Frio County gardeners in Zone 8b 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 Frio County, TX. Local conditions may vary. Last updated: April 2026.