The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when it's a good idea to plant trailing portulaca by referring to the USDA zone info for Harrisburg.

Planting Calendar for Trailing Portulaca

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

You can not plant trailing portulaca until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant trailing portulaca in Harrisburg 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 trailing portulaca and expect a good harvest is probably August. You probably don't want to wait any later than that or else your trailing portulaca may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your trailing portulaca indoors.

Last Frost Date

The average date of last frost is April 15 in Harrisburg. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Harrisburg is an average the actual date of last frost will vary from year to year. Half of the time in Harrisburg you get a frost after April 15 so be sure to be ready to cover your trailing portulaca in the event of one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Harrisburg

You may be interested in your other planting guides for Harrisburg.