One of the best tools that you have as gardeners to help us determine 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.

It's a good idea to estimate when it's the best time to plant onions by referring to the USDA zone info for San Leandro.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them much earlier than more sensitive plants.

The earliest that you can plant onions in San Leandro is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably October. Any later than that and your onions may not have a chance to really do well. Starting your onions indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on January 31 in San Leandro. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for San Leandro is an average the actual date of last frost changes from year to year. Half of the time in San Leandro you get a frost after January 31 so be sure to be ready to protect your onions if you have a late frost.

USDA Zone Info for San Leandro

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 Leandro

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