The USDA Zone info is a great tool for gardeners to help us estimate 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.

A way of figuring out when it's the best time to plant runner beans is to use the USDA zone info for Northfield.

Planting Calendar for Runner beans

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

It's probably not a good idea to plant runner beans until after the last frost has passed because they require warm weather.

The earliest that you can plant runner beans in Northfield 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. Any later than that and your runner beans may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your runner beans indoors.

Last Frost Date

In Northfield the average date of last frost happens on May 15. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Northfield is an average the actual date of last frost will vary from year to year. Since half of the time in Northfield it frosts late in the year after May 15 be ready to cover your runner beans if you have one of those late frosts.

USDA Zone Info for Northfield

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 Northfield

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