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.

The earliest that you can plant skullcap in Zone 1a can be estimated by checking out the USDA zone info.

Planting Calendar for Skullcap

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

Skullcap require warm weather which tells us that it's necessary 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 1a is June. However, you really should wait until July if you don't want to take any chances.

The last month that you can plant skullcap and expect a good harvest is probably July. If you wait any later than that and your skullcap may not have a chance to fully mature. If you are starting your skullcap indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on June 15 in Zone 1a. You should expect an average low temperature of -60°F in the coldest months of winter.

Since the USDA zone info for Zone 1a may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Zone 1a it frosts late in the year after June 15 so make sure that you are prepared to cover your skullcap if you have one of those late frosts.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-60°F
Highest Expected Low	-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in your other planting guides for Zone 1a.