One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. 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 the best time to plant scallions is to refer to the USDA zone info for Philadelphia.

Planting Calendar for Scallions

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

Scallions are barely cold tolerant which means that you can plant them slightly earlier than other frost tender plants.

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

Last Frost Date

On average all chance of 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.

Always keep in mind that USDA zone info for Philadelphia may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Philadelphia it frosts late in the year after April 15 be ready to protect your scallions 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.