One of the best tools that you have as gardeners to help us determine 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.

The USDA zone info for Zone 4b should be looked at to figure out when it's the best time to plant sweet potato vine.

Planting Calendar for Sweet Potato Vine

Frost tolerance for sweet potato vine:	Not tolerant of frost.
When to plant:	After the last frost.

Since sweet potato vine are not cold tolerant you need to wait until after the last frost has passed before you can plant them.

The earliest that you can plant sweet potato vine in Zone 4b 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 potato vine and expect a good harvest is probably August. Any later than that and your sweet potato vine may not have a chance to fully mature. If you are starting your sweet potato vine indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Zone 4b. You can expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 4b and it is different every year. Since half of the time in Zone 4b there is a last frost after May 15 be ready to protect your sweet potato vine if you have a late frost.

USDA Zone Info for Zone 4b

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 Zone 4b

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