One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of getting a good idea when to plant calibrachoa is to check out the USDA zone info for Philadelphia.

Planting Calendar for Calibrachoa

Frost tolerance for calibrachoa:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Calibrachoa are barely cold tolerant which tells us that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant calibrachoa in Philadelphia 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 calibrachoa and expect a good harvest is probably August. Any later than that and your calibrachoa may not have a chance to really do well. Starting your calibrachoa indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Philadelphia. It might get as low as 0°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. Half of the time in Philadelphia last frost occurs after April 15 so make sure that you are prepared to protect your calibrachoa if you have one of those late frosts.

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.