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.

The best time to plant watercress in Sammamish can be determined by using 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.

Since watercress do ok in moderate cold you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant watercress in Sammamish 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 grow to maturity. You can get started a couple of weeks earlier by starting your watercress indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Sammamish. You can expect an average low temperature of 15°F in the coldest months of winter.

It's important to remember that USDA zone info for Sammamish is an average and the actual date of last frost changes from year to year. Half of the time in Sammamish last frost occurs after March 15 so be sure to be ready to protect your watercress in the event of a surprise late frost.

USDA Zone Info for Sammamish

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Sammamish

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