When can I plant String beans in Zone 4a

One of the first steps we take when we are determining our gardening schedule is find our USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for our area.

A way of making a decision about when you can plant string beans is to use the USDA zone info for Zone 4a.


Planting Calendar for String beans

Frost tolerance for string beans: Not tolerant of frost.
When you should plant them: After the last frost has passed.

String beans do not do well in cold weather which means that it's necessary to wait until it warms up after the last frost before you can plant them.

JanFebMarAprMayJunJulAugSepOctNovDec
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A good time to plant string beans
Possibly ok, but a risky time to plant string beans
Probably not a good time to plant string beans

The earliest that you can plant string 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 string beans and expect a good harvest is probably August. Any later than that and your string beans may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your string beans indoors.

Last Frost Date

In Zone 4a the average date of last frost happens on May 15. In the coldest months of winter we should expect an average low temperature of -30°F.

Always keep in mind that USDA zone info for Zone 4a is an average and our actual date of last frost changes from year to year. Since half of the time in Zone 4a it frosts late in the year after May 15 be ready to cover your string beans if we have 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 our other planting guides for Zone 4a.