One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to figure out when it's possible to plant watercress by referring to the USDA zone info for Ballwin.

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 one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant watercress in Ballwin 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. You can get started a few weeks earlier by starting your watercress indoors.

Last Frost Date

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

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ballwin and it changes from year to year. Half of the time in Ballwin last frost occurs after April 15 so always be ready to cover your watercress if you have a surprise late frost.

USDA Zone Info for Ballwin

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 Ballwin

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