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When to Plant Sweet Corn in Smith County, TN

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.

Smith County, Tennessee is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 28, giving you a growing season of approximately 201 days.

At an elevation of 3,829 feet, Smith County receives approximately 41.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94ยฐF, providing good warmth for Sweet Corn during the growing season.

Smith County, TN (Zone 7a) Long season
201 days
Last Spring Frost April 10
201 growing days
First Fall Frost October 28

Smith County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (94 days to spare)
Transplant: Apr 5 🍅 Harvest: Jun 7 – Jul 19
Recommended (50%) ✓ Fits season (96 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 12 – Jul 24
Safe Start (90%) ✓ Fits season (98 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 23 – Aug 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 245 gal / 100 sq ft
Sweet Corn needs ~1,538 GDD — county provides 4,120 GDD Excellent fit

Sweet Corn Planting Timeline โ€” Smith County, TN

Sweet Corn Planting Calendar

Activity When Date Range
Direct Sow April 17 Apr 17 โ€“ May 8
Harvest June 19 Jun 19 โ€“ Jul 31

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 Direct Sow
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 7a

Growing Season

201 days

Growing Tips for Smith 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 Smith County, TN?

Smith County is in Zone 7a with an average last frost of April 10. Plan your Sweet Corn planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Smith County, TN?

Smith County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Smith County gardeners in Zone 7a 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 Smith County, TN. Local conditions may vary. Last updated: April 2026.