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

You should be able to figure out when it's a good idea to plant watercress by using the USDA zone info for Lewistown.

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 are barely cold tolerant.

The earliest that you can plant watercress in Lewistown 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 really do well. You can get started a little bit earlier by starting your watercress indoors.

Last Frost Date

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

Since the USDA zone info for Lewistown is an average the actual date of last frost will vary from year to year. Half of the time in Lewistown there is a last frost after May 15 so make sure that you are ready to cover your watercress in the event of a late frost.

USDA Zone Info for Lewistown

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 Lewistown

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