One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Philadelphia it's a good idea to determine when to plant saxifraga.

Planting Calendar for Saxifraga

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

You can plant saxifraga just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant saxifraga 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 saxifraga and expect a good harvest is probably August. If you wait any later than that and your saxifraga may not have a chance to fully mature. You can get started a little bit earlier by starting your saxifraga indoors.

Last Frost Date

On average the last frost is on March 15 in Philadelphia. In the coldest months of winter you can expect an average low temperature of 10°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Philadelphia and it will vary from year to year. Half of the time in Philadelphia there is a last frost after March 15 so be sure to be ready to protect your saxifraga in the event of 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.