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When to Plant Sweet Corn in King 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.

King County, Texas is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is November 7, giving you a growing season of approximately 221 days.

At an elevation of 3,170 feet, King County receives approximately 60.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 99ยฐF, so Sweet Corn may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Sweet Corn will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Corn root diseases.

King County, TX (Zone 7b) Long season
221 days
Last Spring Frost March 31
221 growing days
First Fall Frost November 7

King County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.8-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (117 days to spare)
Transplant: Mar 23 🍅 Harvest: May 25 – Jul 6
Recommended (50%) ✓ Fits season (116 days to spare)
Transplant: Mar 31 🍅 Harvest: Jun 2 – Jul 14
Safe Start (90%) ✓ Fits season (116 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 17 – Jul 29

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
1.1″/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 ~1,819 GDD — county provides 5,359 GDD Excellent fit

Sweet Corn Planting Timeline โ€” King County, TX

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow April 7 Apr 7 โ€“ Apr 28
Harvest June 9 Jun 9 โ€“ Jul 21

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Direct Sow
May โ€”
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

221 days

Growing Tips for King 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 King County, TX?

King County is in Zone 7b with an average last frost of March 31. Plan your Sweet Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is King County, TX?

King County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is November 7.

๐ŸŒฑ

Plan Your Garden with Confidence

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