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.

A common way of estimating when it's a good idea to plant skullcap is to look at the USDA zone info for Berlin.

Planting Calendar for Skullcap

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

Since skullcap require warm weather it's necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant skullcap in Berlin is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant skullcap and expect a good harvest is probably August. If you wait any later than that and your skullcap may not have a chance to grow to maturity. Starting your skullcap indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on May 15 in Berlin. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Berlin is just an average the actual date of last frost changes from year to year. Half of the time in Berlin it frosts late in the year after May 15 so just be sure to be ready to protect your skullcap if you have a late frost.

USDA Zone Info for Berlin

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Berlin

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