One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In South Haven you can estimate when it's a good idea to plant periwinkles by reviewing the USDA zone info.

Planting Calendar for Periwinkles

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

You should not plant periwinkles until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant periwinkles in South Haven 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. Starting your periwinkles indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in South Haven. In the coldest months of winter you can expect an average low temperature of -5°F.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for South Haven and it changes from year to year. Half of the time in South Haven it frosts late in the year after April 15 so just be sure to be ready to cover your periwinkles in the event of a late frost.

USDA Zone Info for South Haven

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in South Haven

You may be interested in your other planting guides for South Haven.