When to Plant Radish in Delaware County, IA
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, Iowa is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.
At an elevation of 974 feet, Delaware County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Radish to ensure they mature before fall.
Delaware County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.8
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 Delaware County
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (6.0–6.8) is within Radish's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Delaware County is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.6%) — Radish will thrive.
How to Plant Radish
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Radish
Sow every 2.4 weeks. Last sowing by Sep 02 to harvest before frost.
For a dedicated fall crop, sow by Jul 15.
Plant Water Budget
Radish Planting Timeline — Delaware County, IA
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 25 | Apr 25 – May 16 |
| Fall Sowing | July 15 | Jul 15 – Jul 29 |
| Harvest | May 23 | May 23 – Jun 13 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow Harvest |
| June | Harvest |
| July | Fall Sowing |
| August | — |
| September | — |
| 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: ideal
🗺️ USDA Zone
Zone 4b
📆 Growing Season
158 days in Delaware County
Growing Tips for Radish in Delaware County
Direct sow Radish outdoors after May 02 in Delaware County when soil has warmed and frost danger has passed.
Your generous 158.0-day season in Delaware 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
Level Up Your Garden
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Delaware County, IA?
Delaware County is in Zone 4b with an average last frost of May 2. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Delaware County, IA?
Delaware County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Delaware County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.
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