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 reviewing the USDA zone info for Philadelphia it's a good idea to estimate when it's possible to plant osteospermum.

Planting Calendar for Osteospermum

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

Osteospermum do well in moderate cold which means that you can plant them earlier than other plants that might not handle the cold.

The earliest that you can plant osteospermum 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 osteospermum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your osteospermum may not have a chance to fully mature. Starting your osteospermum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Philadelphia the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

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 can change quite a bit from year to year. Since half of the time in Philadelphia you get surprised by a frost after March 15 be ready to cover your osteospermum if you have one of those late frosts.

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.