One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant skullcap in North Chicago should be figured out by referring to the USDA zone info.

Planting Calendar for Skullcap

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

Skullcap are not cold tolerant which means that you must wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant skullcap in North Chicago 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 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

The average date of last frost is April 15 in North Chicago. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for North Chicago may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in North Chicago there is a last frost after April 15 be ready to cover your skullcap in the event of a late frost.

USDA Zone Info for North Chicago

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in North Chicago

You may be interested in your other planting guides for North Chicago.