One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Charleston should be used to estimate when you can plant portulaca.

Planting Calendar for Portulaca

Frost tolerance for portulaca:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Portulaca are not cold tolerant which tells us that you must wait until it warms up after the last frost before you can plant them.

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

Last Frost Date

The average date of last frost is April 15 in Charleston. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Charleston may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Charleston it frosts late in the year after April 15 so make sure that you are ready to cover your portulaca if you have a surprise late frost.

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.