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When to Plant Sweet Corn in Callahan 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.

Callahan County, Texas is in USDA Zone 7b. The average last spring frost is March 21 and the first fall frost is November 16, giving you a growing season of approximately 240 days.

At an elevation of 4,241 feet, Callahan County receives approximately 59.1 inches of rainfall annually with predominantly loam soil. Summer highs average 91ยฐF, 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.

Callahan County, TX (Zone 7b) Long season
240 days
Last Spring Frost March 21
240 growing days
First Fall Frost November 16

Callahan County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (139 days to spare)
Transplant: Mar 10 🍅 Harvest: May 12 – Jun 23
Recommended (50%) ✓ Fits season (135 days to spare)
Transplant: Mar 21 🍅 Harvest: May 23 – Jul 4
Safe Start (90%) ✓ Fits season (130 days to spare)
Transplant: Apr 12 🍅 Harvest: Jun 14 – Jul 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Sweet Corn needs ~1,369 GDD — county provides 4,380 GDD Excellent fit

Sweet Corn Planting Timeline โ€” Callahan County, TX

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow March 28 Mar 28 โ€“ Apr 18
Harvest May 30 May 30 โ€“ Jul 11

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7b

Growing Season

240 days

Growing Tips for Callahan 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

Level Up Your Garden

Frequently Asked Questions

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

Callahan County is in Zone 7b with an average last frost of March 21. Plan your Sweet Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Callahan County, TX?

Callahan County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 21 and first fall frost is November 16.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Callahan County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

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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 Callahan County, TX. Local conditions may vary. Last updated: April 2026.