The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Coralville should be read to determine when to plant black radish.

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 tend to make it in mild cold which tells us that you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant black radish in Coralville 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. If you wait any later than that and your black radish may not have a chance to grow to maturity. If you are starting your black radish indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Coralville and it is different every year. Half of the time in Coralville you get surprised by a frost after April 15 so be sure to be ready to cover your black radish if you have one of those late frosts.

USDA Zone Info for Coralville

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 Coralville

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