The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant tree onions in National City should be estimated by reviewing the USDA zone info.

Planting Calendar for Tree onions

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

Tree onions do well in very little 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 tree 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 tree onions and expect a good harvest is probably September. Any later than that and your tree onions may not have a chance to really do well. You can get started a couple of weeks earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost has passed is on January 31 in National City. You should expect an average low temperature of 35°F in the coldest months of winter.

Always keep in mind that USDA zone info for National City may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in National City there is a last frost after January 31 be ready to protect your tree onions 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.