Before planting it is a good idea to find your USDA Zone info to estimate 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 the best time to plant bunching onions by looking at the USDA zone info.

Planting Calendar for Bunching Onions

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

Bunching Onions tend to make it in a tiny bit of cold which means that you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant bunching onions 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 bunching onions and expect a good harvest is probably September. Any later than that and your bunching onions may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your bunching onions indoors.

Last Frost Date

The average date of last frost is January 31 in National City. It might get as low as 35°F during the coldest months of winter.

Since the USDA zone info for National City may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in National City you get surprised by a frost after January 31 be ready to protect your bunching onions in the event of a 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.