The USDA Zone info is a great tool for gardeners to help us determine 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.

One way of making a decision about when it's possible to plant columbine is to check out the USDA zone info for Harrisburg.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant columbine a little earlier in the year because they do well in moderate cold.

The earliest that you can plant columbine in Harrisburg is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant columbine and expect a good harvest is probably September. If you wait any later than that and your columbine may not have a chance to really do well. If you are starting your columbine indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Harrisburg. In the coldest months of winter you can expect an average low temperature of 0°F.

Since the USDA zone info for Harrisburg is not always accurate the actual date of last frost is different every year. Half of the time in Harrisburg there is a last frost after April 15 so just be sure to be ready to cover your columbine in the event of a late frost.

USDA Zone Info for Harrisburg

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 Harrisburg

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