One of the best tools that you have as gardeners to help us determine 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.

The USDA zone info for Waterloo can be looked at to estimate when it's the best time to plant columbine.

Planting Calendar for Columbine

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

Columbine do well in moderate cold which means that you can get them planted earlier than more sensitive 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. If you wait 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 couple of weeks 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 -20°F.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Waterloo and it changes from year to year. Since half of the time in Waterloo you get a frost after April 15 be ready to protect your columbine in the event of one of those late frosts.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Waterloo

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