One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to figure out when it's a good idea to plant skullcap by reviewing the USDA zone info for Blue Island.

Planting Calendar for Skullcap

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

Skullcap are not cold tolerant which tells us that it is important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant skullcap in Blue Island 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. You probably don't want to wait any later than that or else your skullcap may not have a chance to really do well. 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

The average date of last frost is April 15 in Blue Island. You should expect an average low temperature of -10°F in the coldest months of winter.

Remember that USDA zone info for Blue Island is just an average and the actual date of last frost is different every year. Half of the time in Blue Island there is a last frost after April 15 so make sure that you are ready to protect your skullcap in the event of one of those late frosts.

USDA Zone Info for Blue Island

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Blue Island

You may be interested in your other planting guides for Blue Island.