Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Boston can be used to estimate when it's a good idea to plant skullcap.

Planting Calendar for Skullcap

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

It's probably not a good idea to plant skullcap until after the last frost because they require warm weather.

The earliest that you can plant skullcap in Boston 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 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 really do well. You can get started a few weeks earlier by starting your skullcap indoors.

Last Frost Date

The average date of last frost is April 15 in Boston. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Boston is just an average the actual date of last frost will vary from year to year. Since half of the time in Boston you get a frost after April 15 be ready to protect your skullcap if you have a surprise late frost.

USDA Zone Info for Boston

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

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

Plants to Grow in Boston

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