Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when to plant onions in Berkeley by referring to the USDA zone info.

Planting Calendar for Onions

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

Onions can survive in quite a bit of cold which tells us that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant onions in Berkeley 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. You probably don't want to wait any later than that or else your onions may not have a chance to really do well. If you are starting your onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is January 31 in Berkeley. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for Berkeley is an average the actual date of last frost is different every year. Half of the time in Berkeley you get surprised by a frost after January 31 so make sure that you are prepared to protect your onions in the event of a late frost.

USDA Zone Info for Berkeley

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 Berkeley

You may be interested in your other planting guides for Berkeley.