Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Harrisburg can be read to figure out when you can plant celosia.

Planting Calendar for Celosia

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

Celosia do not do well in cold weather which means that it is necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant celosia 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 celosia and expect a good harvest is probably August. Any later than that and your celosia may not have a chance to fully mature. If you are starting your celosia indoors then you might be able to get away with starting them a couple of weeks earlier.

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 just an average the actual date of last frost is different every year. Half of the time in Harrisburg it frosts late in the year after April 15 so be sure to be ready to protect your celosia if you have one of those late frosts.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Harrisburg

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