Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 Edinburgh can be looked at to determine 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 moderate cold which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant watercress in Edinburgh 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. You probably don't want to wait any later than that or else your watercress may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your watercress indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Edinburgh. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Edinburgh is an average the actual date of last frost is different every year. Half of the time in Edinburgh there is a last frost after April 15 so be sure to be ready to cover your watercress if you have one of those late frosts.

USDA Zone Info for Edinburgh

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 Edinburgh

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