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.

In San Rafael you can estimate when it's a good idea to plant tree onions by reviewing 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.

Since tree onions do ok in moderate cold you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant tree onions in San Rafael 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 fully mature. Starting your tree onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Rafael. You should expect an average low temperature of 30°F in the coldest months of winter.

It's important to remember that USDA zone info for San Rafael may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in San Rafael last frost occurs after January 31 be ready to cover your tree onions in the event of a late frost.

USDA Zone Info for San Rafael

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 San Rafael

You may be interested in your other planting guides for San Rafael.