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When to Plant Radish in Delaware County, PA

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.

Delaware County, Pennsylvania is in USDA Zone 7a. The average last spring frost is April 16 and the first fall frost is October 24, giving you a growing season of approximately 191 days.

At an elevation of 1,094 feet, Delaware County receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Radish during the growing season.

Delaware County, PA (Zone 7a) Moderate season
191 days
Last Spring Frost April 16
191 growing days
First Fall Frost October 24

Delaware County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (139 days to spare)
Transplant: Apr 13 🍅 Harvest: May 11 – Jun 1
Recommended (50%) ✓ Fits season (142 days to spare)
Transplant: Apr 16 🍅 Harvest: May 14 – Jun 4
Safe Start (90%) ✓ Fits season (128 days to spare)
Transplant: May 11 🍅 Harvest: Jun 8 – Jun 29

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 268 gal / 100 sq ft
Radish needs ~477 GDD — county provides 3,199 GDD Excellent fit

Radish Planting Timeline โ€” Delaware County, PA

Radish Planting Calendar

Activity When Date Range
Direct Sow April 2 Apr 2 โ€“ Apr 23
Fall Sowing August 15 Aug 15 โ€“ Aug 29
Harvest April 30 Apr 30 โ€“ May 21

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
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

191 days

Growing Tips for Delaware 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 Delaware County, PA?

Delaware County is in Zone 7a with an average last frost of April 16. Plan your Radish planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Delaware County, PA?

Delaware County, Pennsylvania is in USDA Hardiness Zone 7a. The average last spring frost is April 16 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

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