The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of making a decision about when it's possible to plant aubrieta is to look at the USDA zone info for Philadelphia.

Planting Calendar for Aubrieta

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

Aubrieta are moderately cold tolerant which means that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant aubrieta 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 aubrieta and expect a good harvest is probably September. If you wait any later than that and your aubrieta may not have a chance to fully mature. If you are starting your aubrieta indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Philadelphia the average date of last frost happens on April 15. 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 just an average because it is based on the USDA zone info for Philadelphia and it changes from year to year. Half of the time in Philadelphia it frosts late in the year after April 15 so be sure to be ready to cover your aubrieta 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.