Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of making a decision about when it's a good idea to plant polygonums is to examine the USDA zone info for Owatonna.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant polygonums until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant polygonums in Owatonna is May. However, you really should wait until June 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. You probably don't want to wait any later than that or else your polygonums may not have a chance to really do well. Starting your polygonums indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Owatonna. You can expect an average low temperature of -25°F in the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Owatonna and it will vary from year to year. Half of the time in Owatonna there is a last frost after May 15 so make sure that you are prepared to protect your polygonums in the event of one of those late frosts.

USDA Zone Info for Owatonna

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Owatonna

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