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

You should be able to figure out when you can plant watercress by using the USDA zone info for Honolulu.

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 well in very little cold which means that you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant watercress in Honolulu 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 watercress and expect a good harvest is probably November. You probably don't want to wait any later than that or else your watercress may not have a chance to really do well. If you are starting your watercress indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Honolulu it never frosts. It might get as low as 50°F during the coldest months of winter.

Always keep in mind that USDA zone info for Honolulu may not be accurate from year to year and the actual date of last frost changes from year to year. Since it never frosts in Honolulu you do not have to be ready to cover your watercress if you have a late frost.

USDA Zone Info for Honolulu

Here is the info for USDA Zone 12a.

Average Date of Last Frost (spring)	Never
Average Date of First Frost (fall)	Never
Lowest Expected Low	50°F
Highest Expected Low	55°F

This means that on a really cold year, the coldest it will get is 50°F. On most years you should be prepared to experience lows near 55°F.

Plants to Grow in Honolulu

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