The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 it's the best time to plant portulaca.

Planting Calendar for Portulaca

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

Since portulaca do not do well in cold weather you need to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant portulaca 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 portulaca and expect a good harvest is probably September. If you wait any later than that and your portulaca may not have a chance to really do well. If you are starting your portulaca indoors then you might be able to get away with starting them 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 may not be accurate from year to year because it is based on the USDA zone info for Charleston and it changes from year to year. Half of the time in Charleston last frost occurs after February 15 so make sure that you are prepared to cover your portulaca if you have 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.