Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of determining when it's the best time to plant begonias is to use the USDA zone info for San Diego.

Planting Calendar for Begonias

Frost tolerance for begonias:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Begonias do not do well in cold weather which tells us that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant begonias in San Diego 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 begonias and expect a good harvest is probably September. Any later than that and your begonias may not have a chance to grow to maturity. You can get started a little bit earlier by starting your begonias indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in San Diego. You should expect an average low temperature of 20°F in the coldest months of winter.

Since the USDA zone info for San Diego is an average the actual date of last frost changes from year to year. Half of the time in San Diego there is a last frost after February 15 so make sure that you are prepared to protect your begonias if you have one of those late frosts.

USDA Zone Info for San Diego

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in San Diego

You may be interested in your other planting guides for San Diego.