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.

One way of making a decision about when it's a good idea to plant cerastium is to refer to the USDA zone info for Rock Island.

Planting Calendar for Cerastium

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

Cerastium are one of those plants that can tolerate a little bit of cold weather which tells us that you can start planting them earlier than more sensitive plants.

The earliest that you can plant cerastium in Rock Island 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 cerastium and expect a good harvest is probably September. Any later than that and your cerastium may not have a chance to fully mature. You can get started a little bit earlier by starting your cerastium indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Rock Island. In the coldest months of winter you can expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Rock Island is just an average and the actual date of last frost will vary from year to year. Since half of the time in Rock Island it frosts late in the year after April 15 be ready to protect your cerastium if you have one of those late frosts.

USDA Zone Info for Rock Island

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 Rock Island

You may be interested in your other planting guides for Rock Island.