Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of getting a good idea when it's a good idea to plant sunflowers is to refer to the USDA zone info for Charleston.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After the last frost.

Sunflowers are not cold tolerant which tells us that you must wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant sunflowers 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 sunflowers and expect a good harvest is probably September. Any later than that and your sunflowers may not have a chance to really do well. Starting your sunflowers 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 not always accurate because it is based on the USDA zone info for Charleston and it can change quite a bit from year to year. Since half of the time in Charleston it frosts late in the year after February 15 be ready to protect your sunflowers in the event of one of those late frosts.

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.