When to Plant Radish in Knox 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.
Knox County, Tennessee is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 29, giving you a growing season of approximately 202 days.
At an elevation of 2,448 feet, Knox County receives approximately 47.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Radish during the growing season.
Knox County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-7
Drainage
Well Drained
Plant Planting Risk Windows
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
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Radish Planting Timeline — Knox County, TN
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 27 | Mar 27 – Apr 17 |
| Fall Sowing | August 20 | Aug 20 – Sep 3 |
| Harvest | April 24 | Apr 24 – May 15 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | Direct Sow Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
22–35 days
Soil pH
6 – 7
USDA Zone
Zone 7a
Growing Season
202 days
Growing Tips for Knox 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
Level Up Your Garden
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Knox County, TN?
Knox County is in Zone 7a with an average last frost of April 10. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Knox County, TN?
Knox County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 29.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Knox County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.
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