One of the first steps you take when you are estimating 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 earliest that you can plant skullcap in Spearfish can be determined by looking at the USDA zone info.

Planting Calendar for Skullcap

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

Since skullcap require warm weather it is important to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant skullcap in Spearfish 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 fully mature. You can get started a few weeks earlier by starting your skullcap indoors.

Last Frost Date

On average the last frost is on April 15 in Spearfish. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Spearfish is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Spearfish you get surprised by a frost after April 15 be ready to cover your skullcap if you have a surprise late frost.

USDA Zone Info for Spearfish

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 Spearfish

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