One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant skullcap in Charleston 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.

It's a bad idea to plant skullcap until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant skullcap in Charleston is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant skullcap and expect a good harvest is probably September. Any later than that and your skullcap may not have a chance to really do well. Starting your skullcap indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Charleston the average date of last frost happens on February 15. It might get as low as 20°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Charleston and it is different every year. Half of the time in Charleston you get surprised by a frost after February 15 so make sure that you are prepared to protect your skullcap if you have a surprise late frost.

USDA Zone Info for Charleston

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°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 25°F.

Plants to Grow in Charleston

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