One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for San Mateo can be used to figure out when it's a good idea to plant fennel.

Planting Calendar for Fennel

Frost tolerance for fennel:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Fennel are very cold tolerant which means that you can plant them much earlier than more sensitive plants.

The earliest that you can plant fennel 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 fennel and expect a good harvest is probably October. If you wait any later than that and your fennel may not have a chance to grow to maturity. Starting your fennel indoors is a great way to get them started a little bit earlier.

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.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for San Mateo and it can change quite a bit from year to year. Since half of the time in San Mateo you get surprised by a frost after January 31 be ready to protect your fennel if you have 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.