One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By using the USDA zone info for South Bay you should be able to estimate when it's possible to plant tree onions.

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 ok in some cold which tells us that you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant tree onions in South Bay 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. If you are starting your tree onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost is on January 31 in South Bay. You can expect an average low temperature of 30°F in the coldest months of winter.

Since the USDA zone info for South Bay is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in South Bay there is a last frost after January 31 so just be sure to be ready to cover your tree onions if you have a late frost.

USDA Zone Info for South Bay

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in South Bay

You may be interested in your other planting guides for South Bay.