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

The USDA zone info for Pomona should be used to determine when it's the best time to plant onions.

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 tells us that you can start planting them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant onions in Pomona 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. If you wait any later than that and your onions may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your onions indoors.

Last Frost Date

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

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Pomona and it is different every year. Half of the time in Pomona there is a last frost after January 31 so just be sure to be ready to cover your onions if you have one of those late frosts.

USDA Zone Info for Pomona

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 Pomona

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