One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By reviewing the USDA zone info for Michigan City you should be able to determine when to plant periwinkles.

Planting Calendar for Periwinkles

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

Since periwinkles require warm weather you really should wait until after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Michigan City 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 grow to maturity. Starting your periwinkles indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Michigan City. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Michigan City may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Michigan City last frost occurs after April 15 so make sure that you are ready to protect your periwinkles if you have one of those late frosts.

USDA Zone Info for Michigan City

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Michigan City

You may be interested in your other planting guides for Michigan City.