Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to determine when it's a good idea to plant black radish by referring to the USDA zone info for Ottumwa.

Planting Calendar for Black radish

Frost tolerance for black radish:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Black radish are moderately cold tolerant which means that you can get them planted earlier than other frost tender plants.

The earliest that you can plant black radish in Ottumwa is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant black radish and expect a good harvest is probably September. Any later than that and your black radish may not have a chance to fully mature. If you are starting your black radish indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Ottumwa the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Ottumwa and it is different every year. Half of the time in Ottumwa you get a frost after April 15 so be sure to be ready to cover your black radish if you have a late frost.

USDA Zone Info for Ottumwa

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Ottumwa

You may be interested in your other planting guides for Ottumwa.