One of the first steps you take when you are estimating 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 will be able to estimate when it's possible to plant hollyhocks by using the USDA zone info for San Mateo.

Planting Calendar for Hollyhocks

Frost tolerance for hollyhocks:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Hollyhocks can survive in moderate cold which tells us that you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant hollyhocks in San Mateo is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant hollyhocks and expect a good harvest is probably October. You probably don't want to wait any later than that or else your hollyhocks may not have a chance to fully mature. If you are starting your hollyhocks indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Since the USDA zone info for San Mateo is an average the actual date of last frost will vary from year to year. Since half of the time in San Mateo last frost occurs after January 31 be ready to cover your hollyhocks in the event of one of those late frosts.

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.