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

The USDA zone info for Duluth should be looked at to figure out when it's the best time to plant runner beans.

Planting Calendar for Runner beans

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

It's probably a bad idea to plant runner beans until after the last frost because they are not cold tolerant.

The earliest that you can plant runner beans in Duluth 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 runner beans and expect a good harvest is probably August. If you wait any later than that and your runner beans may not have a chance to grow to maturity. If you are starting your runner beans indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Duluth the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -30°F.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Duluth and it will vary from year to year. Half of the time in Duluth last frost occurs after May 15 so make sure that you are prepared to cover your runner beans in the event of a surprise late frost.

USDA Zone Info for Duluth

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 Duluth

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