Before planting it is a good idea to find your USDA Zone info to determine 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.

One way of estimating when you can plant skullcap is to check out the USDA zone info for Zone 4b.

Planting Calendar for Skullcap

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

Skullcap 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 skullcap in Zone 4b 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. Any later than that and your skullcap may not have a chance to really do well. You can get started a couple of weeks earlier by starting your skullcap indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4b. You can expect an average low temperature of -25°F in the coldest months of winter.

Remember that USDA zone info for Zone 4b is just an average and the actual date of last frost changes from year to year. Since half of the time in Zone 4b last frost occurs after May 15 be ready to protect your skullcap if you have a late frost.

USDA Zone Info for Zone 4b

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 Zone 4b

You may be interested in your other planting guides for Zone 4b.