Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's the best time to plant watercress in San Jose by using 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 one of those plants that can tolerate a tiny bit of cold weather which means that you can plant them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant watercress in San Jose 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 grow to maturity. You can get started a little bit earlier by starting your watercress indoors.

Last Frost Date

On average the last frost has passed is on February 15 in San Jose. You can expect an average low temperature of 25°F in the coldest months of winter.

Keep in mind that USDA zone info for San Jose is just an average and the actual date of last frost will vary from year to year. Half of the time in San Jose it frosts late in the year after February 15 so make sure that you are ready to cover your watercress if you have a late frost.

USDA Zone Info for San Jose

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 San Jose

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