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.

One way of getting a good idea when it's the best time to plant skullcap is to examine the USDA zone info for Northbrook.

Planting Calendar for Skullcap

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

You really shouldn't plant skullcap until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant skullcap in Northbrook 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. You can get started a couple of weeks earlier by starting your skullcap indoors.

Last Frost Date

On average the last frost is on April 15 in Northbrook. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Northbrook is an average the actual date of last frost is different every year. Since half of the time in Northbrook you get surprised by a frost after April 15 be ready to protect your skullcap in the event of a surprise late frost.

USDA Zone Info for Northbrook

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 Northbrook

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