The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of getting a good idea when you can plant radishes is to examine the USDA zone info for Zone 4a.

Planting Calendar for Radishes

Frost tolerance for radishes:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Radishes do well in cold which tells us that you can get them planted much earlier than more sensitive plants.

The earliest that you can plant radishes in Zone 4a is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant radishes and expect a good harvest is probably August. Any later than that and your radishes may not have a chance to grow to maturity. You can get started a little bit earlier by starting your radishes indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4a. It might get as low as -30°F during the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4a is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Zone 4a it frosts late in the year after May 15 so be sure to be ready to protect your radishes if you have a surprise late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.