When to Plant Onions in Mission Viejo, CA

The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to determine when to plant onions by looking at the USDA zone info for Mission Viejo.


Planting Calendar for Onions

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

You can plant onions quite a bit earlier in the year because they do well in cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant onions
Possibly ok, but a risky time to plant onions
Probably not a good time to plant onions

The earliest that you can plant onions in Mission Viejo 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 fully mature. 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 Mission Viejo. You should expect an average low temperature of 35°F in the coldest months of winter.

Since the USDA zone info for Mission Viejo is an average the actual date of last frost is different every year. Since half of the time in Mission Viejo last frost occurs after January 31 be ready to cover your onions in the event of one of those late frosts.

USDA Zone Info for Mission Viejo

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)January 31
Average Date of First Frost (fall)December 15
Lowest Expected Low35°F
Highest Expected Low40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Mission Viejo

You may be interested in your other planting guides for Mission Viejo.