One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant lisianthus in Philadelphia should be determined by checking out the USDA zone info.

Planting Calendar for Lisianthus

Frost tolerance for lisianthus:	Not tolerant of frost.
When to plant:	After the last frost.

Lisianthus are not cold tolerant which means that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant lisianthus in Philadelphia is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant lisianthus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lisianthus may not have a chance to grow to maturity. Starting your lisianthus indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Philadelphia. It might get as low as 0°F during the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Philadelphia and it can change quite a bit from year to year. Half of the time in Philadelphia it frosts late in the year after April 15 so make sure that you are ready to protect your lisianthus if you have a surprise 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.