Before planting it is a good idea to find your USDA Zone info to determine 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.

In Charleston you can figure out when it's possible to plant nasturtium by using the USDA zone info.

Planting Calendar for Nasturtium

Frost tolerance for nasturtium:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since nasturtium are not cold tolerant it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant nasturtium 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 nasturtium and expect a good harvest is probably August. If you wait any later than that and your nasturtium may not have a chance to really do well. Starting your nasturtium 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.

Just be sure to remember 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. Half of the time in Charleston there is a last frost after April 15 so make sure that you are prepared to cover your nasturtium in the event of a 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.