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.

The first chance to plant watercress in San Mateo should be determined by looking at the USDA zone info.

Planting Calendar for Watercress

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

Watercress are barely cold tolerant which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant watercress 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 watercress and expect a good harvest is probably September. If you wait any later than that and your watercress may not have a chance to fully mature. Starting your watercress indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In San Mateo the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

It's important to remember that USDA zone info for San Mateo may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in San Mateo there is a last frost after January 31 so make sure that you are prepared to protect your watercress 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.