The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In San Diego you can estimate when you can plant bunching onions by reviewing 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.

Since bunching onions are barely cold tolerant you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant bunching onions in San Diego 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. You probably don't want to wait any later than that or else your bunching onions may not have a chance to grow to maturity. Starting your bunching onions indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is January 31 in San Diego. You should expect an average low temperature of 35°F in the coldest months of winter.

Since the USDA zone info for San Diego may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in San Diego you get surprised by a frost after January 31 so be sure to be ready to cover your bunching onions if you have a surprise late frost.

USDA Zone Info for San Diego

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 San Diego

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