One of the first steps you take when you are making a decision about 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.

You can figure out when it's possible to plant periwinkles in New Haven by using the USDA zone info.

Planting Calendar for Periwinkles

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

Periwinkles require warm weather which tells us that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant periwinkles in New 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. You probably don't want to wait any later than that or else your periwinkles may not have a chance to really do well. You can get started a little bit earlier by starting your periwinkles indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in New Haven. In the coldest months of winter you should expect an average low temperature of -10°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for New Haven and it can change quite a bit from year to year. Since half of the time in New Haven last frost occurs after April 15 be ready to cover your periwinkles if you have a late frost.

USDA Zone Info for New Haven

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 New Haven

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