The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Rock Falls should be reviewed to estimate when you can plant skullcap.

Planting Calendar for Skullcap

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

Since skullcap are not cold tolerant you have to wait until after the last frost has passed before you can plant them.

The earliest that you can plant skullcap in Rock Falls 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

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

It's important to remember that USDA zone info for Rock Falls is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Rock Falls there is a last frost after April 15 so make sure that you are ready to cover your skullcap in the event of one of those late frosts.

USDA Zone Info for Rock Falls

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 Rock Falls

You may be interested in your other planting guides for Rock Falls.