The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Crookston you can figure out when it's the best time to plant polygonums by reviewing the USDA zone info.

Planting Calendar for Polygonums

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

Since polygonums are not cold tolerant you must wait until after the last frost has passed before you can plant them.

The earliest that you can plant polygonums in Crookston 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. If you wait any later than that and your polygonums may not have a chance to grow to maturity. You can get started a little bit earlier by starting your polygonums indoors.

Last Frost Date

The average date of last frost is May 15 in Crookston. In the coldest months of winter you should expect an average low temperature of -30°F.

Since the USDA zone info for Crookston is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Crookston there is a last frost after May 15 so make sure that you are prepared to cover your polygonums in the event of one of those late frosts.

USDA Zone Info for Crookston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Crookston

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