The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Lisle you will be able to determine when it's possible to plant skullcap.

Planting Calendar for Skullcap

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

Skullcap do not do well in cold weather which means that you need to 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 Lisle 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 grow to maturity. You can get started a few weeks earlier by starting your skullcap indoors.

Last Frost Date

In Lisle the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Lisle may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Lisle you get a frost after April 15 so always be ready to cover your skullcap in the event of one of those late frosts.

USDA Zone Info for Lisle

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 Lisle

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