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.

By looking at the USDA zone info for Janesville you should be able to estimate when to plant scarlet runner beans.

Planting Calendar for Scarlet Runner Beans

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

Scarlet Runner Beans do not do well in cold weather which tells us that it's necessary to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

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

Last Frost Date

On average the last frost is on April 15 in Janesville. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Janesville and it changes from year to year. Half of the time in Janesville it frosts late in the year after April 15 so always be ready to protect your scarlet runner beans if you have a surprise late frost.

USDA Zone Info for Janesville

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

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

Plants to Grow in Janesville

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