Before planting it is a good idea to find your USDA Zone info to estimate 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 first opportunity to plant impatiens in Charleston should be figured out by referring to the USDA zone info.

Planting Calendar for Impatiens

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

It's probably not a good idea to plant impatiens until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant impatiens 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 impatiens and expect a good harvest is probably August. You probably don't want to wait any later than that or else your impatiens may not have a chance to grow to maturity. Starting your impatiens indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Charleston. It might get as low as -10°F during the coldest months of winter.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Charleston and it will vary from year to year. Half of the time in Charleston last frost occurs after April 15 so just be sure to be ready to cover your impatiens in the event of 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.