The USDA Zone info is a great tool for gardeners to help us determine 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.

A common way of determining when to plant pearl onions is to consult the USDA zone info for San Rafael.

Planting Calendar for Pearl onions

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

You can plant pearl onions slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant pearl 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 pearl onions and expect a good harvest is probably September. Any later than that and your pearl onions may not have a chance to fully mature. Starting your pearl onions indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on January 31 in San Rafael. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for San Rafael may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in San Rafael last frost occurs after January 31 so always be ready to cover your pearl onions in the event of one of those late frosts.

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.