One of the best tools that you have as gardeners to help us estimate 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.

A common way of getting a good idea when it's possible to plant watercress is to look at the USDA zone info for Hawaiian Gardens.

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 tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant watercress in Hawaiian Gardens 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 fully mature. 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 Hawaiian Gardens the average date of last frost happens on January 31. It might get as low as 35°F during the coldest months of winter.

Since the USDA zone info for Hawaiian Gardens is not always accurate the actual date of last frost is different every year. Since half of the time in Hawaiian Gardens there is a last frost after January 31 be ready to cover your watercress if you have a surprise late frost.

USDA Zone Info for Hawaiian Gardens

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Hawaiian Gardens

You may be interested in your other planting guides for Hawaiian Gardens.