One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when it's a good idea to plant polygonums by reviewing the USDA zone info for Waterloo.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After the last frost.

You can not plant polygonums until after the last frost because they are not cold tolerant.

The earliest that you can plant polygonums in Waterloo 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 polygonums and expect a good harvest is probably August. If you wait any later than that and your polygonums may not have a chance to really do well. Starting your polygonums indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Waterloo. In the coldest months of winter you should expect an average low temperature of -10°F.

Keep in mind that USDA zone info for Waterloo is just an average and the actual date of last frost is different every year. Since half of the time in Waterloo last frost occurs after April 15 be ready to cover your polygonums 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.