One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Iowa City you can estimate when you can plant dianthus by reviewing the USDA zone info.

Planting Calendar for Dianthus

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

Dianthus are moderately cold tolerant which means that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant dianthus in Iowa City 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 dianthus and expect a good harvest is probably September. If you wait any later than that and your dianthus may not have a chance to really do well. If you are starting your dianthus indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Iowa City the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Iowa City and it is different every year. Since half of the time in Iowa City last frost occurs after April 15 be ready to protect your dianthus in the event of a surprise late frost.

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.