Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant calibrachoa in Charleston should be figured out by referring to the USDA zone info.

Planting Calendar for Calibrachoa

Frost tolerance for calibrachoa:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Calibrachoa do well in very little cold which tells us that you can plant them just a tiny bit earlier in the year than other frost tender plants.

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

The last month that you can plant calibrachoa and expect a good harvest is probably September. You probably don't want to wait any later than that or else your calibrachoa may not have a chance to grow to maturity. If you are starting your calibrachoa indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Charleston the average date of last frost happens on February 15. You can expect an average low temperature of 20°F in the coldest months of winter.

Since the USDA zone info for Charleston is just an average the actual date of last frost changes from year to year. Since half of the time in Charleston you get a frost after February 15 be ready to protect your calibrachoa in the event of 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.