Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's possible to plant skullcap in Iowa City by checking out the USDA zone info.

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 tells us that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant skullcap in Iowa City 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 fully mature. Starting your skullcap indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Iowa City. In the coldest months of winter you can expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Iowa City is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Iowa City there is a last frost after April 15 be ready to protect your skullcap if you have a surprise late frost.

USDA Zone Info for Iowa City

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 Iowa City

You may be interested in your other planting guides for Iowa City.