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 Ontario can be used to determine when it's a good idea 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.

Since cerastium do well in moderate cold you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant cerastium in Ontario 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. If you wait any later than that and your cerastium may not have a chance to really do well. Starting your cerastium indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Ontario. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Ontario may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Ontario it frosts late in the year after April 15 be ready to cover your cerastium in the event of a surprise late frost.

USDA Zone Info for Ontario

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Ontario

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