Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Amsterdam it's possible to figure out when it's possible to plant periwinkles.

Planting Calendar for Periwinkles

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

Since periwinkles require warm weather it is necessary to wait until after the last frost when the weather gets warmer before you can plant them.

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

Last Frost Date

In Amsterdam the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Keep in mind that USDA zone info for Amsterdam is not always accurate and the actual date of last frost is different every year. Half of the time in Amsterdam it frosts late in the year after April 15 so make sure that you are ready to cover your periwinkles if you have a late frost.

USDA Zone Info for Amsterdam

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Amsterdam

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