When to Plant Periwinkles in Hummelstown, PA

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant periwinkles in Hummelstown should be estimated 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.

Since periwinkles require warm weather it is necessary to wait until after all chance of frost has passed before you can plant them.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant periwinkles
Possibly ok, but a risky time to plant periwinkles
Probably not a good time to plant periwinkles

The earliest that you can plant periwinkles in Hummelstown 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. If you wait any later than that and your periwinkles may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your periwinkles indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Hummelstown. In the coldest months of winter you can expect an average low temperature of 0°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Hummelstown and it will vary from year to year. Since half of the time in Hummelstown 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 Hummelstown

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low0°F
Highest Expected Low5°F

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

Plants to Grow in Hummelstown

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