One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

The USDA zone info for Ontario can be reviewed to determine when it's possible to plant cerastium.

Planting Calendar for Cerastium

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

You can plant cerastium just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant cerastium in Ontario is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant cerastium and expect a good harvest is probably October. Any later than that and your cerastium may not have a chance to fully mature. If you are starting your cerastium 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 January 31 in Ontario. It might get as low as 30°F during the coldest months of winter.

Keep in mind that USDA zone info for Ontario is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Ontario last frost occurs after January 31 be ready to cover your cerastium if you have one of those late frosts.

USDA Zone Info for Ontario

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Ontario

You may be interested in your other planting guides for Ontario.