One of the first steps you take when you are figuring out your gardening schedule is find your 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 best time to plant zinnia in Charleston can be determined by referring to the USDA zone info.

Planting Calendar for Zinnia

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

Since zinnia require warm weather it is important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant zinnia 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 zinnia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your zinnia may not have a chance to really do well. You can get started a little bit earlier by starting your zinnia indoors.

Last Frost Date

The average date of last frost is April 15 in Charleston. In the coldest months of winter you should expect an average low temperature of -5°F.

It's important to remember 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 last frost occurs after April 15 so make sure that you are ready to cover your zinnia if you have a surprise late frost.

USDA Zone Info for Charleston

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Charleston

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