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.

You should be able to estimate when it's possible to plant alternaria by using the USDA zone info for Charleston.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Alternaria are not cold tolerant which tells us that you need to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant alternaria in Charleston 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 alternaria and expect a good harvest is probably August. Any later than that and your alternaria may not have a chance to really do well. You can get started a few weeks earlier by starting your alternaria indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Charleston. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Charleston is just an average the actual date of last frost will vary from year to year. Half of the time in Charleston there is a last frost after April 15 so just be sure to be ready to cover your alternaria if you have one of those late frosts.

USDA Zone Info for Charleston

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Charleston

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