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.

A way of estimating when it's possible to plant snow-in summer is to refer to the USDA zone info for Philadelphia.

Planting Calendar for Snow-in Summer

Frost tolerance for snow-in summer:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Snow-in Summer tend to make it in mild cold which means that you can plant them a little bit earlier in the year than more sensitive plants.

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

Last Frost Date

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

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Philadelphia and it will vary from year to year. Since half of the time in Philadelphia there is a last frost after April 15 be ready to protect your snow-in summer 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.