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 can determine when it's the best time to plant watercress in Zimmerman by referring to 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.

You can plant watercress just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant watercress in Zimmerman is April. However, you really should wait until May 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. 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

The average date of last frost is May 15 in Zimmerman. You can expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Zimmerman is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Zimmerman you get a frost after May 15 so make sure that you are ready to cover your watercress if you have a late frost.

USDA Zone Info for Zimmerman

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zimmerman

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