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.

It's possible to estimate when it's a good idea to plant cosmos by referring to the USDA zone info for Isle of Palms.

Planting Calendar for Cosmos

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

Cosmos do ok in moderate cold which tells us that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant cosmos in Isle of Palms 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 cosmos and expect a good harvest is probably August. Any later than that and your cosmos may not have a chance to grow to maturity. If you are starting your cosmos indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on March 15 in Isle of Palms. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for Isle of Palms is just an average the actual date of last frost is different every year. Half of the time in Isle of Palms you get a frost after March 15 so make sure that you are prepared to protect your cosmos in the event of a surprise late frost.

USDA Zone Info for Isle of Palms

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Isle of Palms

You may be interested in your other planting guides for Isle of Palms.