The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant blue throatwort in Elk River can be estimated by referring to the USDA zone info.

Planting Calendar for Blue Throatwort

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

You really shouldn't plant blue throatwort until after the last frost because they are not cold tolerant.

The earliest that you can plant blue throatwort in Elk River 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 blue throatwort and expect a good harvest is probably August. If you wait any later than that and your blue throatwort may not have a chance to fully mature. If you are starting your blue throatwort indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Elk River the average date of last frost happens on May 15. 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 an average because it is based on the USDA zone info for Elk River and it is different every year. Since half of the time in Elk River it frosts late in the year after May 15 be ready to cover your blue throatwort if you have a surprise late frost.

USDA Zone Info for Elk River

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 Elk River

You may be interested in your other planting guides for Elk River.