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.

In Charleston you can figure out when to plant alyssum by referring to the USDA zone info.

Planting Calendar for Alyssum

Frost tolerance for alyssum:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Alyssum can survive in a bit of cold which tells us that you can plant them earlier in the year than other frost tender plants.

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

The last month that you can plant alyssum and expect a good harvest is probably October. Any later than that and your alyssum may not have a chance to fully mature. Starting your alyssum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on February 15 in Charleston. It might get as low as 20°F during the coldest months of winter.

Always keep in mind that USDA zone info for Charleston is not always accurate and the actual date of last frost 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 alyssum if you have a 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.