Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Ann Arbor it's possible to estimate when it's possible 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 has passed.

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

The earliest that you can plant runner beans in Ann Arbor is April. However, you really should wait until May 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. You can get started a couple of weeks earlier by starting your runner beans indoors.

Last Frost Date

In Ann Arbor the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Ann Arbor and it will vary from year to year. Since half of the time in Ann Arbor you get surprised by a frost after April 15 be ready to protect your runner beans in the event of a late frost.

USDA Zone Info for Ann Arbor

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ann Arbor

You may be interested in your other planting guides for Ann Arbor.