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When to Plant Radish in Putnam County, TN

Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

Putnam County, Tennessee is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 26, giving you a growing season of approximately 199 days.

At an elevation of 1,813 feet, Putnam County receives approximately 51.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Radish during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.

Putnam County, TN (Zone 7a) Moderate season
199 days
Last Spring Frost April 10
199 growing days
First Fall Frost October 26

Putnam County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (149 days to spare)
Transplant: Apr 6 🍅 Harvest: May 4 – May 25
Recommended (50%) ✓ Fits season (150 days to spare)
Transplant: Apr 10 🍅 Harvest: May 8 – May 29
Safe Start (90%) ✓ Fits season (152 days to spare)
Transplant: Apr 22 🍅 Harvest: May 20 – Jun 10

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
Radish needs ~456 GDD — county provides 3,184 GDD Excellent fit

Radish Planting Timeline โ€” Putnam County, TN

Radish Planting Calendar

Activity When Date Range
Direct Sow March 27 Mar 27 โ€“ Apr 17
Fall Sowing August 17 Aug 17 โ€“ Aug 31
Harvest April 24 Apr 24 โ€“ May 15

Plant 0.5" deep ยท 2" apart ยท Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

22โ€“35 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

199 days

Growing Tips for Putnam County

Direct sow every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Level Up Your Garden

Frequently Asked Questions

When should I plant Radish in Putnam County, TN?

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

What planting zone is Putnam County, TN?

Putnam County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 26.

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Plan Your Garden with Confidence

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