One of the first steps you take when you are determining 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.

By looking at the USDA zone info for Ukiah you should be able to estimate when it's a good idea to plant watercress.

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 do ok in moderate cold which means that you can start planting them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant watercress in Ukiah 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. You probably don't want to wait any later than that or else your watercress may not have a chance to grow to maturity. If you are starting your watercress indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Ukiah the average date of last frost happens on February 15. You should expect an average low temperature of 20°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Ukiah is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Ukiah you get surprised by a frost after February 15 be ready to cover your watercress if you have a late frost.

USDA Zone Info for Ukiah

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Ukiah

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