Before planting it is a good idea to find your USDA Zone info to figure out 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 Coralville can be looked at to figure out when it's possible to plant dianthus.

Planting Calendar for Dianthus

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

Dianthus do ok in some cold which tells us that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant dianthus 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 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 grow to maturity. If you are starting your dianthus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Coralville. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Coralville may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Coralville you get surprised by a frost after April 15 be ready to cover your dianthus if you have a surprise late frost.

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.