Before planting it is a good idea to find your USDA Zone info to determine 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.

By looking at the USDA zone info for Philadelphia it's possible to determine when to plant borage.

Planting Calendar for Borage

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

Borage do well in moderate cold which tells us that you can start planting them earlier than other frost tender plants.

The earliest that you can plant borage 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 borage and expect a good harvest is probably September. You probably don't want to wait any later than that or else your borage may not have a chance to grow to maturity. You can get started a little bit earlier by starting your borage indoors.

Last Frost Date

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

Just be sure 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 last frost occurs after April 15 so always be ready to cover your borage 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.