One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant watercress in Clay should be determined by checking out 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.

Watercress tend to make it in very little cold which tells us that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant watercress in Clay 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. If you are starting your watercress indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Clay. You can expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Clay is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Clay there is a last frost after April 15 be ready to cover your watercress if you have one of those late frosts.

USDA Zone Info for Clay

Here is the info for USDA Zone 7b.

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

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

Plants to Grow in Clay

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