One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In San Bruno you can determine when it's possible to plant bunching onions by checking out 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 do ok in moderate cold 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 San Bruno 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. Starting your bunching onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is January 31 in San Bruno. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for San Bruno may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in San Bruno last frost occurs after January 31 so make sure that you are ready to cover your bunching onions if you have a surprise late frost.

USDA Zone Info for San Bruno

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 San Bruno

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