The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Grinnell can be reviewed to estimate when to plant string beans.

Planting Calendar for String beans

Frost tolerance for string beans:	Not tolerant of frost.
When to plant:	After the last frost.

Since string beans are not cold tolerant you have to wait until after the last frost before you can plant them.

The earliest that you can plant string beans in Grinnell 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 string beans and expect a good harvest is probably August. You probably don't want to wait any later than that or else your string beans may not have a chance to grow to maturity. Starting your string beans indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Always keep in mind that USDA zone info for Grinnell is not always accurate and the actual date of last frost changes from year to year. Half of the time in Grinnell you get surprised by a frost after April 15 so make sure that you are prepared to protect your string beans in the event of a late frost.

USDA Zone Info for Grinnell

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 Grinnell

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