One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when you can plant cerastium in Philadelphia by reviewing the USDA zone info.

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 a little earlier in the year because they are moderately cold tolerant.

The earliest that you can plant cerastium in Philadelphia 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 really do well. If you are starting your cerastium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Philadelphia. In the coldest months of winter you should expect an average low temperature of 10°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Philadelphia and it is different every year. Half of the time in Philadelphia you get surprised by a frost after March 15 so just be sure to be ready to protect your cerastium in the event of a surprise late frost.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Philadelphia

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