One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Dubuque can be read to figure out 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 require warm weather which tells us that you need to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant skullcap in Dubuque 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. If you wait any later than that and your skullcap may not have a chance to fully mature. Starting your skullcap indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Dubuque. In the coldest months of winter you can expect an average low temperature of -20°F.

Since the USDA zone info for Dubuque is an average the actual date of last frost is different every year. Half of the time in Dubuque you get a frost after April 15 so make sure that you are prepared to protect your skullcap in the event of one of those late frosts.

USDA Zone Info for Dubuque

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Dubuque

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