Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Thief River Falls should be reviewed to determine when it's the best time to plant radishes.

Planting Calendar for Radishes

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

Radishes are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them a quite a bit earlier than other frost tender plants.

The earliest that you can plant radishes in Thief River Falls 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. If you are starting your radishes indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Thief River Falls. In the coldest months of winter you should expect an average low temperature of -35°F.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Thief River Falls and it will vary from year to year. Since half of the time in Thief River Falls you get a frost after May 15 be ready to cover your radishes in the event of a late frost.

USDA Zone Info for Thief River Falls

Here is the info for USDA Zone 3b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-35°F
Highest Expected Low	-30°F

This means that on a really cold year, the coldest it will get is -35°F. On most years you should be prepared to experience lows near -30°F.

Plants to Grow in Thief River Falls

You may be interested in your other planting guides for Thief River Falls.