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When to Plant Radish in Caldwell County, NC

Caldwell County, North Carolina Zone 7b May

Caldwell County, North Carolina gardeners: here's your May plan

May is a pivotal month for Caldwell County, North Carolina gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 10
Avg. first frost October 26
Soil temp (4") 70°F
Watering Low
Pest pressure Moderate
Daylight 13.9 hrs
  1. Bring in the radish

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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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.

Caldwell County, North Carolina is in USDA Zone 7b. 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 1,108 feet, Caldwell County receives approximately 46 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91°F, providing good warmth for Radish during the growing season. Clay soil retains moisture well for Radish, but amend with compost to improve drainage and prevent root rot.

Caldwell County, NC (Zone 7b) Moderate season
199 days
Last Spring Frost April 10
199 growing days
First Fall Frost October 26
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Caldwell County Soil Profile

Soil Type

Clay Loam

Soil pH

5.3-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (149 days to spare)
Transplant: Apr 5 🍅 Harvest: May 3 – May 24
Recommended (50%) ✓ Fits season (150 days to spare)
Transplant: Apr 10 🍅 Harvest: May 8 – May 29
Safe Start (90%) ✓ Fits season (147 days to spare)
Transplant: Apr 24 🍅 Harvest: May 22 – Jun 12

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 Caldwell County

How your county's soil matches Radish's growing requirements.

Soil pH

Your soil pH (5.3–6.5) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Your soil has 33% clay, which can cause forked or stunted roots for Radish. Use raised beds with loose, sandy mix for best results.

Drainage

Drainage is adequate for Radish.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Radish.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Radish

11
successive plantings in your 199-day season

Sow every 2.4 weeks. Last sowing by Sep 21 to harvest before frost.

For a dedicated fall crop, sow by Aug 17.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 3.6" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 2.2" 3.9" 0" ✅ Rainfall sufficient
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 4.7" 0" ✅ Rainfall sufficient
Jul 2.2" 4.4" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 3.8" 0" ❄️ Dormant
Dec 3.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Caldwell 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 needs ~520 GDD — county provides 3,631 GDD Excellent fit

Radish Planting Timeline — Caldwell County, NC

Radish Planting Calendar

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

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

Month-by-Month Timeline

MonthActivities
January
February
March Direct Sow
April Direct Sow Harvest
May Harvest
June
July
August Fall Sowing
September
October
November
December
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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 7b

📆 Growing Season

199 days in Caldwell County

Growing Tips for Radish in Caldwell County

Direct sow Radish outdoors after April 10 in Caldwell County when soil has warmed and frost danger has passed.

With Caldwell County's clay soil (33% clay), work in 3-4 inches of compost before planting Radish. Avoid tilling when soil is wet to prevent compaction.

Summer highs in Caldwell County reach 91°F — grow Radish as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 199.0-day season in Caldwell 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

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Caldwell County, NC?

Caldwell County is in Zone 7b 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 Caldwell County, NC?

Caldwell County, North Carolina is in USDA Hardiness Zone 7b. The average last spring frost is April 10 and first fall frost is October 26.

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Your Caldwell County Garden Planner — Free

A 24-page printable planner built for Caldwell County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Caldwell County, NC. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.