One of the first steps you take when you are estimating your gardening schedule is find your 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.

You should be able to determine when you can plant periwinkles by referring to the USDA zone info for Carnegie.

Planting Calendar for Periwinkles

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

You really shouldn't plant periwinkles until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant periwinkles in Carnegie 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 really do well. Starting your periwinkles indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Carnegie. It might get as low as -5°F during the coldest months of winter.

Remember that USDA zone info for Carnegie is just an average and the actual date of last frost changes from year to year. Since half of the time in Carnegie there is a last frost after April 15 be ready to protect your periwinkles in the event of a surprise late frost.

USDA Zone Info for Carnegie

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 Carnegie

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