One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

In Waterloo you can figure out 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 one of those plants that can tolerate a little bit of cold weather which means that you can get them planted earlier than other frost tender plants.

The earliest that you can plant columbine in Waterloo 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. Any later than that and your columbine may not have a chance to really do well. Starting your columbine indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Waterloo the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Waterloo is just an average the actual date of last frost changes from year to year. Half of the time in Waterloo it frosts late in the year after April 15 so make sure that you are prepared to protect your columbine if you have a late frost.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 6a.

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

Plants to Grow in Waterloo

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