One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of estimating when to plant argyranthemum is to refer to the USDA zone info for Costa Mesa.

Planting Calendar for Argyranthemum

Frost tolerance for argyranthemum:	Not tolerant of frost.
When to plant:	After the last frost.

Argyranthemum are not cold tolerant which tells us that you really should wait until it warms up after the last frost before you can plant them.

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

Last Frost Date

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

Just be sure to remember that USDA zone info for Costa Mesa is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Costa Mesa last frost occurs after January 31 so make sure that you are prepared to protect your argyranthemum in the event of 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.