When to Plant Radish in Mahaska 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.
Mahaska County, Iowa is in USDA Zone 5a. The average last spring frost is April 27 and the first fall frost is October 9, giving you a growing season of approximately 165 days.
At an elevation of 511 feet, Mahaska County receives approximately 32.2 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.
Mahaska County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-7.3
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.
Plant Water Budget
Radish Planting Timeline — Mahaska County, IA
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 13 | Apr 13 – May 4 |
| Fall Sowing | July 31 | Jul 31 – Aug 14 |
| Harvest | May 11 | May 11 – Jun 1 |
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 | Fall Sowing |
| September | — |
| 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 5a
Growing Season
165 days
Growing Tips for Mahaska 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 Mahaska County, IA?
Mahaska County is in Zone 5a with an average last frost of April 27. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mahaska County, IA?
Mahaska County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 27 and first fall frost is October 9.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mahaska County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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