Before planting it is a good idea to find your USDA Zone info to figure out 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.

A common way of determining when you can plant periwinkles is to look at the USDA zone info for Spencer.

Planting Calendar for Periwinkles

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

Periwinkles are not cold tolerant which means that it's important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant periwinkles in Spencer 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 periwinkles and expect a good harvest is probably August. Any later than that and your periwinkles may not have a chance to fully mature. You can get started a little bit earlier by starting your periwinkles indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Spencer. In the coldest months of winter you can expect an average low temperature of -20°F.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Spencer and it changes from year to year. Half of the time in Spencer you get a frost after April 15 so always be ready to cover your periwinkles if you have a surprise late frost.

USDA Zone Info for Spencer

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 Spencer

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