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.

By referring to the USDA zone info for Philadelphia it's a good idea to estimate when it's a good idea to plant coral bells.

Planting Calendar for Coral Bells

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

You can plant coral bells just a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant coral bells 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 coral bells and expect a good harvest is probably September. You probably don't want to wait any later than that or else your coral bells may not have a chance to grow to maturity. If you are starting your coral bells indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Philadelphia. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Philadelphia is not always accurate the actual date of last frost is different every year. Since half of the time in Philadelphia last frost occurs after March 15 be ready to cover your coral bells in the event of a 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.