One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when it's the best time to plant pearl onions in San Mateo by checking out the USDA zone info.

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 do ok in moderate cold.

The earliest that you can plant pearl onions in San Mateo 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. If you wait any later than that and your pearl onions may not have a chance to really do well. You can get started a couple of weeks earlier by starting your pearl onions indoors.

Last Frost Date

On average the last frost has passed is on January 31 in San Mateo. You should expect an average low temperature of 30°F in the coldest months of winter.

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

USDA Zone Info for San Mateo

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 Mateo

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