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

By looking at the USDA zone info for San Diego you will be able to determine when it's the best time to plant corn.

Planting Calendar for Corn

Frost tolerance for corn:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant corn until after the last frost because they are not cold tolerant.

The earliest that you can plant corn 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 corn and expect a good harvest is probably September. If you wait any later than that and your corn may not have a chance to grow to maturity. If you are starting your corn indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is 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 can change quite a bit from year to year. Since half of the time in San Diego you get surprised by a frost after February 15 be ready to cover your corn in the event of a surprise late frost.

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.