Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant arabis in Philadelphia can be determined by referring to the USDA zone info.

Planting Calendar for Arabis

Frost tolerance for arabis:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

You can plant arabis much earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

The earliest that you can plant arabis 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 arabis and expect a good harvest is probably September. You probably don't want to wait any later than that or else your arabis may not have a chance to fully mature. If you are starting your arabis indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Philadelphia is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Philadelphia you get surprised by a frost after April 15 be ready to protect your arabis 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.