One of the best tools that you have as gardeners to help us figure out 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.

The first chance to plant campanula in Philadelphia can be figured out by reviewing the USDA zone info.

Planting Calendar for Campanula

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

Campanula can survive in moderate cold which tells us that you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant campanula 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 campanula and expect a good harvest is probably September. You probably don't want to wait any later than that or else your campanula may not have a chance to really do well. Starting your campanula indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Philadelphia. You can expect an average low temperature of 0°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Philadelphia and it changes from year to year. Since half of the time in Philadelphia you get a frost after April 15 be ready to cover your campanula in the event of a late frost.

USDA Zone Info for Philadelphia

Here is the info for USDA Zone 7a.

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

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

Plants to Grow in Philadelphia

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