One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when it's possible to plant portulaca by using the USDA zone info for Coralville.

Planting Calendar for Portulaca

Frost tolerance for portulaca:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably a bad idea to plant portulaca until after the last frost when the weather gets warmer because they require warm weather.

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

Last Frost Date

The average date of last frost is April 15 in Coralville. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Coralville is just an average the actual date of last frost changes from year to year. Half of the time in Coralville there is a last frost after April 15 so make sure that you are ready to cover your portulaca if you have a 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.