The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Ann Arbor should be looked at to estimate 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.

Since watercress do ok in moderate cold you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant watercress in Ann Arbor 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. You probably don't want to wait any later than that or else your watercress may not have a chance to really do well. You can get started a couple of weeks earlier by starting your watercress indoors.

Last Frost Date

In Ann Arbor the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Ann Arbor and it is different every year. Half of the time in Ann Arbor it frosts late in the year after April 15 so make sure that you are prepared to protect your watercress in the event of one of those late frosts.

USDA Zone Info for Ann Arbor

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ann Arbor

You may be interested in your other planting guides for Ann Arbor.