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

The first chance to plant dahlias in Costa Mesa can be figured out by reviewing the USDA zone info.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since dahlias are not cold tolerant it's necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant dahlias in Costa Mesa is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant dahlias and expect a good harvest is probably September. You probably don't want to wait any later than that or else your dahlias may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your dahlias indoors.

Last Frost Date

The average date of last frost is January 31 in Costa Mesa. You can expect an average low temperature of 35°F in the coldest months of winter.

Since the USDA zone info for Costa Mesa is just an average the actual date of last frost changes from year to year. Since half of the time in Costa Mesa you get a frost after January 31 be ready to cover your dahlias if you have one of those late frosts.

USDA Zone Info for Costa Mesa

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Costa Mesa

You may be interested in your other planting guides for Costa Mesa.