The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of determining when it's possible to plant celery is to look at the USDA zone info for Philadelphia.

Planting Calendar for Celery

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

Since celery are barely cold tolerant you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Philadelphia. It might get as low as 10°F during the coldest months of winter.

Keep in mind that USDA zone info for Philadelphia is not always accurate and the actual date of last frost is different every year. Half of the time in Philadelphia there is a last frost after March 15 so make sure that you are ready to cover your celery if you have a surprise late frost.

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.