One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Harrisburg you can estimate when it's a good idea to plant columbine by referring to the USDA zone info.

Planting Calendar for Columbine

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

Columbine are moderately cold tolerant which means that you can get them planted earlier than plants that are more sensitive to the 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 grow to maturity. If you are starting your columbine indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Harrisburg. In the coldest months of winter you should expect an average low temperature of -5°F.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Harrisburg and it can change quite a bit from year to year. Since half of the time in Harrisburg you get a frost after April 15 be ready to protect your columbine if you have a late frost.

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.