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

The earliest that you can plant potatos in Grinnell should be determined by reviewing the USDA zone info.

Planting Calendar for Potatos

Frost tolerance for potatos:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Potatos are one of those plants that can tolerate quite a bit of cold weather which means that you can get them planted much earlier than plants that are more sensitive to the cold.

The earliest that you can plant potatos in Grinnell is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant potatos and expect a good harvest is probably September. Any later than that and your potatos may not have a chance to fully mature. Starting your potatos indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Grinnell may not be accurate from year to year 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 ready to protect your potatos in the event of a surprise 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.