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When to Plant Sweet Corn in Comal 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.

Comal County, Texas is in USDA Zone 9a. The average last spring frost is March 6 and the first fall frost is November 22, giving you a growing season of approximately 261 days.

At an elevation of 1,346 feet, Comal County receives approximately 58.6 inches of rainfall annually with predominantly clay soil. Summer highs average 91°F, providing good warmth for Sweet Corn during the growing season. Clay soil retains moisture well for Sweet Corn, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Corn root diseases.

Comal County, TX (Zone 9a) Long season
261 days
Last Spring Frost March 6
261 growing days
First Fall Frost November 22
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Comal County Soil Profile

Soil Type

Clay

Soil pH

6.7-7.7

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 1.2" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 4.3" 3.8" 0.5" 💧 Light watering
Apr 4.3" 6.6" 0" ✅ Rainfall sufficient
May 4.3" 9.4" 0" ✅ Rainfall sufficient
Jun 4.3" 9.9" 0" ✅ Rainfall sufficient
Jul 4.3" 6.6" 0" ✅ Rainfall sufficient
Aug 4.3" 6.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.9" 0" ✅ Rainfall sufficient
Oct 4.3" 3.9" 0.4" 💧 Light watering
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Comal County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Sweet Corn Planting Timeline — Comal County, TX

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow March 13 Mar 13 – Apr 3
Harvest May 15 May 15 – Jun 26

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

Month-by-Month Timeline

MonthActivities
January
February
March Direct Sow
April Direct Sow
May Harvest
June Harvest
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 9a

📆 Growing Season

261 days in Comal County

Growing Tips for Comal 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 Comal County, TX?

Comal County is in Zone 9a with an average last frost of March 6. Plan your Sweet Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Comal County, TX?

Comal County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 6 and first fall frost is November 22.

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Your Comal County Garden Planner — Free

A 22-page printable planner built for Comal County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Comal County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.