One of the first steps you take when you are estimating your gardening schedule is find your 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 alternanthera in Philadelphia should be estimated by using the USDA zone info.

Planting Calendar for Alternanthera

Frost tolerance for alternanthera:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You can not plant alternanthera until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant alternanthera 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 alternanthera and expect a good harvest is probably August. If you wait any later than that and your alternanthera may not have a chance to really do well. If you are starting your alternanthera indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Philadelphia. You should expect an average low temperature of 10°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Philadelphia is an average and the actual date of last frost changes from year to year. Since half of the time in Philadelphia you get surprised by a frost after March 15 be ready to cover your alternanthera if you have one of those late frosts.

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.