The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant onions in Rancho Santa Margarita should be estimated 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 do well in cold weather which tells us that you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant onions in Rancho Santa Margarita 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. 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

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

Keep in mind that USDA zone info for Rancho Santa Margarita is just an average and the actual date of last frost will vary from year to year. Half of the time in Rancho Santa Margarita last frost occurs after January 31 so always be ready to protect your onions in the event of a late frost.

USDA Zone Info for Rancho Santa Margarita

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 Rancho Santa Margarita

You may be interested in your other planting guides for Rancho Santa Margarita.