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.

The first opportunity to plant polygonums in Grand Forks can be determined by using 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 do not do well in cold weather it is important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant polygonums in Grand Forks 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. Any later than that and your polygonums may not have a chance to really do well. If you are starting your polygonums indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Grand Forks. It might get as low as -30°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Grand Forks is an average and the actual date of last frost will vary from year to year. Since half of the time in Grand Forks there is a last frost after May 15 be ready to protect your polygonums if you have a late frost.

USDA Zone Info for Grand Forks

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 Grand Forks

You may be interested in your other planting guides for Grand Forks.