When to Plant Radish in Sumter County, SC
This month in Sumter County, South Carolina
Your Sumter County, South Carolina garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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.
Sumter County, South Carolina is in USDA Zone 8b. The average last spring frost is March 20 and the first fall frost is November 15, giving you a growing season of approximately 240 days.
At an elevation of 163 feet, Sumter County receives approximately 59.6 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Radish may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Radish will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.
Sumter County Soil Profile
Soil Type
Sandy Loam
Soil pH
4.9-6.3
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.
Soil Compatibility in Sumter County
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (4.9–6.3) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in Sumter County warms quickly in spring but drains fast. Radish will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Radish.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Radish.
How to Plant Radish
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Radish
Sow every 2.4 weeks. Last sowing by Oct 11 to harvest before frost.
For a dedicated fall crop, sow by Sep 06.
Plant Water Budget
Monthly Watering Guide for Radish
Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Radish Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 4.8" | 0" | ❄️ Dormant |
| Feb | — | 5.4" | 0" | ❄️ Dormant |
| Mar | 2.2" | 5.1" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 5.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 7" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 5.3" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| Dec | — | 5.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Sumter County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Radish Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Radish Planting Timeline — Sumter County, SC
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 6 | Mar 6 – Mar 27 |
| Harvest | April 3 | Apr 3 – Apr 24 |
| Fall Sowing | September 6 | Sep 6 – Sep 20 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | Harvest |
| May | — |
| June | — |
| July | — |
| August | — |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
22–35 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8b
📆 Growing Season
240 days in Sumter County
Growing Tips for Radish in Sumter County
Direct sow Radish outdoors after March 20 in Sumter County when soil has warmed and frost danger has passed.
Sandy soil in Sumter County dries quickly — mulch Radish with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
Summer highs in Sumter County reach 97°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.
Your generous 240.0-day season in Sumter County allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.
Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Sumter County, SC?
Sumter County is in Zone 8b with an average last frost of March 20. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sumter County, SC?
Sumter County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 20 and first fall frost is November 15.
Your Sumter County Garden Planner — Free
A 24-page printable planner built for Sumter County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.