The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By using the USDA zone info for Philadelphia you will be able to determine when it's possible to plant bidens.

Planting Calendar for Bidens

Frost tolerance for bidens:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since bidens require warm weather you must wait until after the last frost has passed before you can plant them.

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

The last month that you can plant bidens and expect a good harvest is probably August. If you wait any later than that and your bidens may not have a chance to grow to maturity. If you are starting your bidens indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Philadelphia. In the coldest months of winter you should expect an average low temperature of 0°F.

Remember that USDA zone info for Philadelphia is just an average and the actual date of last frost is different every year. Half of the time in Philadelphia you get surprised by a frost after April 15 so always be ready to cover your bidens 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.