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

You will be able to figure out when it's the best time to plant skullcap by referring to the USDA zone info for Viroqua.

Planting Calendar for Skullcap

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

It's probably a bad idea to plant skullcap until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant skullcap in Viroqua is May. However, you really should wait until June 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. Any later than that and your skullcap may not have a chance to fully mature. You can get started a little bit earlier by starting your skullcap indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Viroqua. It might get as low as -25°F during the coldest months of winter.

Remember that USDA zone info for Viroqua is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Viroqua you get surprised by a frost after May 15 be ready to protect your skullcap in the event of a late frost.

USDA Zone Info for Viroqua

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Viroqua

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