The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Sheldon you can figure out when it's a good idea to plant periwinkles by looking at the USDA zone info.

Planting Calendar for Periwinkles

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

It's a bad idea to plant periwinkles until after the last frost because they are not cold tolerant.

The earliest that you can plant periwinkles in Sheldon 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 periwinkles and expect a good harvest is probably August. If you wait any later than that and your periwinkles may not have a chance to grow to maturity. Starting your periwinkles indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Sheldon. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Sheldon is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Sheldon there is a last frost after May 15 be ready to protect your periwinkles in the event of one of those late frosts.

USDA Zone Info for Sheldon

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 Sheldon

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