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 can determine when it's a good idea to plant tree onions in Rancho Santa Margarita by checking out the USDA zone info.

Planting Calendar for Tree onions

Frost tolerance for tree onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Tree onions do ok in moderate cold which tells us that you can plant them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant tree onions in Rancho Santa Margarita is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant tree onions and expect a good harvest is probably September. Any later than that and your tree onions may not have a chance to grow to maturity. If you are starting your tree 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 Rancho Santa Margarita. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for Rancho Santa Margarita is not always accurate the actual date of last frost is different every year. Since half of the time in Rancho Santa Margarita it frosts late in the year after January 31 be ready to cover your tree onions in the event of a surprise 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.