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.

By reviewing the USDA zone info for Washington you should be able to determine when it's the best time 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 are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant watercress in Washington is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant watercress and expect a good harvest is probably August. If you wait any later than that and your watercress may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your watercress indoors.

Last Frost Date

In Washington the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Washington 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 Washington you get a frost after April 15 so be sure to be ready to protect your watercress if you have a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Washington

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