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

By using the USDA zone info for Commerce City you will be able 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 the last frost has passed.

It's a bad idea to plant skullcap until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant skullcap in Commerce 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. If you wait any later than that and your skullcap may not have a chance to fully mature. If you are starting your skullcap indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Commerce City is just an average the actual date of last frost will vary from year to year. Half of the time in Commerce City there is a last frost after April 15 so always be ready to protect your skullcap in the event of one of those late frosts.

USDA Zone Info for Commerce 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 Commerce City

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