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.

By looking at the USDA zone info for Charleston you should be able to determine when it's a good idea to plant gladiolus.

Planting Calendar for Gladiolus

Frost tolerance for gladiolus:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant gladiolus slightly earlier in the year because they are barely cold tolerant.

The earliest that you can plant gladiolus 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 gladiolus and expect a good harvest is probably August. If you wait any later than that and your gladiolus may not have a chance to fully mature. You can get started a little bit earlier by starting your gladiolus indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on 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 is just an average the actual date of last frost can change quite a bit 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 gladiolus if you have 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.