Before planting it is a good idea to find your USDA Zone info to determine 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 National City you can determine when it's possible to plant sweet corn by checking out the USDA zone info.

Planting Calendar for Sweet corn

Frost tolerance for sweet corn:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant sweet corn just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant sweet corn in National City 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 sweet corn and expect a good harvest is probably September. If you wait any later than that and your sweet corn may not have a chance to grow to maturity. Starting your sweet corn indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in National City. In the coldest months of winter you can expect an average low temperature of 35°F.

Since the USDA zone info for National City is an average the actual date of last frost is different every year. Half of the time in National City there is a last frost after January 31 so be sure to be ready to protect your sweet corn if you have a surprise late frost.

USDA Zone Info for National City

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 National City

You may be interested in your other planting guides for National City.