Before planting it is a good idea to find your USDA Zone info to estimate your garden 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 Northfield you will be able to estimate when to plant sweet potatos.

Planting Calendar for Sweet Potatos

Frost tolerance for sweet potatos:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since sweet potatos do not do well in cold weather it's important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant sweet potatos in Northfield 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 sweet potatos and expect a good harvest is probably August. Any later than that and your sweet potatos may not have a chance to really do well. If you are starting your sweet potatos indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Northfield the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

It's important to remember that USDA zone info for Northfield is an average and the actual date of last frost is different every year. Half of the time in Northfield you get a frost after May 15 so make sure that you are prepared to protect your sweet potatos if you have a surprise late frost.

USDA Zone Info for Northfield

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Northfield

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