One of the first steps you take when you are getting a good idea 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.

By reviewing the USDA zone info for Waterville you will be able to figure out when it's the best time 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.

Periwinkles do not do well in cold weather which tells us that it's important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Waterville 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. If you are starting your periwinkles indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Waterville. It might get as low as -20°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Waterville and it changes from year to year. Since half of the time in Waterville you get surprised by a frost after April 15 be ready to protect your periwinkles if you have a surprise late frost.

USDA Zone Info for Waterville

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 Waterville

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