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.

One way of determining when it's the best time to plant onions is to look at the USDA zone info for Placentia.

Planting Calendar for Onions

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

Since onions are one of those plants that can tolerate quite a bit of cold weather you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant onions in Placentia 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 grow to maturity. If you are starting your onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Placentia and it changes from year to year. Half of the time in Placentia there is a last frost after January 31 so be sure to be ready to cover your onions in the event of one of those late frosts.

USDA Zone Info for Placentia

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 Placentia

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