One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Walla Walla you can figure out when you can plant watercress by looking at 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 tend to make it in some cold which tells us that you can plant them just a tiny bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant watercress in Walla Walla 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. Starting your watercress indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Walla Walla the average date of last frost happens on April 15. You can expect an average low temperature of 0°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Walla Walla is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Walla Walla it frosts late in the year after April 15 be ready to protect your watercress in the event of a surprise late frost.

USDA Zone Info for Walla Walla

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Walla Walla

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