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.

In Costa Mesa you can figure out when it's possible to plant asters by reviewing the USDA zone info.

Planting Calendar for Asters

Frost tolerance for asters:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant asters a little bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

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

The last month that you can plant asters and expect a good harvest is probably October. If you wait any later than that and your asters may not have a chance to grow to maturity. If you are starting your asters 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 when the weather gets warmer is on January 31 in Costa Mesa. You should 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 will vary from year to year. Half of the time in Costa Mesa it frosts late in the year after January 31 so be sure to be ready to cover your asters if you have a surprise late frost.

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.