Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to figure out when it's the best time to plant skullcap by referring to the USDA zone info for Silvis.

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 have 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 Silvis 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. Any later than that and your skullcap may not have a chance to grow to maturity. Starting your skullcap indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Silvis is just an average the actual date of last frost will vary from year to year. Since half of the time in Silvis you get a frost after April 15 be ready to cover your skullcap if you have a late frost.

USDA Zone Info for Silvis

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 Silvis

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