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.

In Mercer Island you can estimate when you can plant runner beans by referring to the USDA zone info.

Planting Calendar for Runner beans

Frost tolerance for runner beans:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You should not plant runner beans until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant runner beans in Mercer Island 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. Starting your runner beans indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Mercer Island. It might get as low as 15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Mercer Island is an average and the actual date of last frost is different every year. Since half of the time in Mercer Island last frost occurs after March 15 be ready to cover your runner beans in the event of a surprise late frost.

USDA Zone Info for Mercer Island

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Mercer Island

You may be interested in your other planting guides for Mercer Island.