One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Cupertino you can estimate when it's possible to plant pearl onions by looking at 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.

Pearl onions can survive in mild cold which tells us that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant pearl onions in Cupertino 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. You probably don't want to wait any later than that or else your pearl onions may not have a chance to grow to maturity. You can get started a little bit earlier by starting your pearl onions indoors.

Last Frost Date

In Cupertino the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Cupertino is not always accurate and the actual date of last frost is different every year. Half of the time in Cupertino last frost occurs after February 15 so just be sure to be ready to cover your pearl onions in the event of one of those late frosts.

USDA Zone Info for Cupertino

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Cupertino

You may be interested in your other planting guides for Cupertino.