One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant alternaria in Iowa City should be figured out by using the USDA zone info.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Alternaria are not cold tolerant which means that it is important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant alternaria in Iowa City is April. However, you really should wait until May if you don't want to take any chances.

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

Last Frost Date

On average the last frost is on April 15 in Iowa City. You can expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that USDA zone info for Iowa City is just an average and the actual date of last frost is different every year. Half of the time in Iowa City there is a last frost after April 15 so always be ready to protect your alternaria if you have one of those late frosts.

USDA Zone Info for Iowa City

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 Iowa City

You may be interested in your other planting guides for Iowa City.