One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when it's possible to plant scarlet runner beans by reviewing the USDA zone info for Zone 4a.

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 require warm weather which means that you have to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant scarlet runner beans in Zone 4a 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 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. You can get started a few weeks earlier by starting your scarlet runner beans indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4a. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Zone 4a is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 4a last frost occurs after May 15 be ready to protect your scarlet runner beans in the event of a late frost.

USDA Zone Info for Zone 4a

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 Zone 4a

You may be interested in your other planting guides for Zone 4a.