Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to determine when to plant larkspur by using the USDA zone info for Philadelphia.

Planting Calendar for Larkspur

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

Since larkspur are very cold tolerant you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant larkspur 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 larkspur and expect a good harvest is probably September. Any later than that and your larkspur may not have a chance to grow to maturity. You can get started a little bit earlier by starting your larkspur indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Philadelphia. You can expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Philadelphia is just an average the actual date of last frost is different every year. Half of the time in Philadelphia you get surprised by a frost after April 15 so make sure that you are ready to cover your larkspur in the event of 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.