One of the best tools that you have as gardeners to help us figure out 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 first opportunity to plant geranium in Charleston should be estimated by looking at the USDA zone info.

Planting Calendar for Geranium

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

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

The earliest that you can plant geranium 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 geranium and expect a good harvest is probably September. If you wait any later than that and your geranium may not have a chance to fully mature. If you are starting your geranium indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Charleston. In the coldest months of winter you should expect an average low temperature of 20°F.

Since the USDA zone info for Charleston is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Charleston you get a frost after February 15 be ready to protect your geranium 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.