One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when it's the best time to plant cerastium by referring to the USDA zone info for Watertown.

Planting Calendar for Cerastium

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

Cerastium are moderately cold tolerant which means that you can start planting them earlier than plants that are more sensitive to the cold.

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

The last month that you can plant cerastium and expect a good harvest is probably August. If you wait 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

The average date of last frost is May 15 in Watertown. You should expect an average low temperature of -30°F in the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Watertown and it changes from year to year. Half of the time in Watertown you get surprised by a frost after May 15 so just be sure to be ready to cover your cerastium if you have one of those late frosts.

USDA Zone Info for Watertown

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°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 -25°F.

Plants to Grow in Watertown

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