Radish planting guide
When to plant radishes
Radishes grow quickly in cool weather. Use the calendar to estimate when to inspect ordinary garden radishes, but use the seed packet and a sample root to decide when they are ready.
Planting method
Sow outdoors
Plant the seed directly in prepared garden soil.
Growing season
Cool weather
Heat can make roots hot, woody or prone to flowering.
Garden radish harvest
3-5 weeks
Inspect roots instead of treating the estimate as a deadline.
Prepared soil depth
At least 6 inches
Long daikon types need a foot or more of loosened soil.
Garden radish planner
Estimate when to start checking roots
Before sowing
Loosen the root zone
Compact or stony soil can distort roots. The reviewed source recommends loosening at least six inches for ordinary radishes and a foot or more for long types.
During growth
Keep growth steady
Drought stress can lead to poor flavor and tough texture. Consistent moisture supports the quick, unstressed growth that produces better roots.
Garden radishes and daikon are not the same schedule
Small garden radishes
The 3-5 week result applies to the familiar small roots described by the Extension source. Begin checking size rather than waiting for the end of the window.
Daikon and long types
These roots need deeper preparation and may follow a different maturity schedule. Use the variety's packet instead of the calculator above.
Do not reuse Minnesota calendar months nationwide
The source lists specific spring and fall months for Minnesota. This page keeps the nationally transferable guidance—cool weather, quick growth and variety-specific maturity—but does not present those state dates as a U.S. planting calendar.
A practical next step
Plan radishes with your local season
Cool-season crops may grow before the last spring frost or after summer heat fades. Use crop-specific soil and temperature guidance too.
- 1. Local dates
Find spring and fall frost dates
See historical 32°F freeze estimates and the matched NOAA station for your ZIP Code.
- 2. Season length
Estimate the frost-date growing window
Compare cautious, middle and less-cautious spring/fall date pairs.
- 3. Harvest timing
Estimate maturity from your seed packet
Use the starting point printed on your seed packet; days to maturity can count from sowing, emergence or transplanting.