One of the best tools that you have as gardeners to help us figure out 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 USDA zone info for Opp can be reviewed to estimate when it's a good idea 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.

Watercress do ok 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 Opp 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. Any later than that and 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

The average date of last frost is March 15 in Opp. In the coldest months of winter you should expect an average low temperature of 10°F.

Just be sure to remember that USDA zone info for Opp is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Opp you get surprised by a frost after March 15 be ready to protect your watercress in the event of a surprise late frost.

USDA Zone Info for Opp

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Opp

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