[jhub]

I have a salad counter full of watercress growing in my small garden pond. I assume it's ok to  eat after a thorough wash?

[Aunt Sally]

I'm not sure I would eat it.  But I guess a thorough washing in salty water would kill any germs

Watercress growers use clean running water in their watercress beds.

This article is interesting:

Growing Watercress

[Salmo]

Apart from the usual danger from eating things from ponds such as salmonella the big danger from wild watercress is liver fluke.

Liver flukes live inside animals, mainly sheep. Their eggs pass out of the sheep in to the ground. The baby flukes then burrow into a tiny snail. When a sheep comes along and grazes it eats the leaves and at the same time eats a snail. The flukes migrate though the animals body to the liver. If there are lots of them they can kill. If you pick wild watercress when out in the countryside you could easily eat a snail and take in flukes. A good washing should prevent this.

I agree with Aunt Sally, I can see no reason why your watercress should not be safe to eat as long as you wash it well.

[arugula]

As Aunt Sally says, watercress does need a flow of water. I have a source of wild watercress near my house, but because of the reasons salmo gives, I wouldn't eat it and prefer to grow landcress.

[jhub]

Thanks for your replies. My pond is raised, has a rigid liner and a filtered fountain.
I'm in an urban area so no sheep.
Decisions, decisions......

[Aunt Sally]

Apart from the usual danger from eating things from ponds such as salmonella the big danger from wild watercress is liver fluke.

Liver flukes live inside animals, mainly sheep. Their eggs pass out of the sheep in to the ground. The baby flukes then burrow into a tiny snail. When a sheep comes along and grazes it eats the leaves and at the same time eats a snail. The flukes migrate though the animals body to the liver. If there are lots of them they can kill. If you pick wild watercress when out in the countryside you could easily eat a snail and take in flukes. A good washing should prevent this.

I agree with Aunt Sally, I can see no reason why your watercress should not be safe to eat as long as you wash it well.

You are nearly correct Salmo.

Fluke eggs are passed in sheep (or cow) droppings and can then wash into the water, it could be a puddle, a stream or a pond.  A small larva hatches from the egg and penetrates into the foot of a water snail.  The larvae then multiply within the body of the snail and eventually 3rd generation larvae are shed into water or onto water films, they form a cyst on fresh water vegetation.  If a sheep (cow) or human then eats the water plant, with a cyst on, a larva hatches from the cyst in their small intestine. This then migrates into the liver and eats its way to the bile duct where it develops into an adult.  Not nice  

So as Salmo and Argyllie says NEVER eat wild watercress.  Unless you have sheep or cows in your garden there will be no fluke present but there could be unpleasant bacteria.  Salmonella (from wild birds) is nasty too  Go buy your water cress from a shop jhub.

[arugula]

I've just read a bit more and it doesn't require a flow of water to grow, but there is something about it needing to be extremely thoroughly rinsed before you consider it safe to eat. More googling required I think.

[Dr_Pepper]

I see loads of it growing in streams round here and I have been sorely tempted to eat some, but after reading up on liver flukes and seeing the sheep in the fields nearby, I've chosen to give it a miss!

[Goosegirl]

In my research of local history here, there used to be a chap called "Tommy Watercress" who went round selling the stuff. Now - having read the posts, and having sheep here, I would take a rain-check, but we also have dykes which can be part fresh and part sea water, so would the salt in the sea water (diluted down the dykes away from the sea) help to sterilise the water cress?

[Aunt Sally]

so would the salt in the sea water (diluted down the dykes away from the sea) help to sterilise the water cress?

I doubt it.

[allotmentann]

It will also grow perfectly happily in large pots filled with ordinary compost, I know, because this is how I have been growing it. I tried this method because of the concerns mentioned. I just make sure to give it lots and lots of water. It is thriving at the minute - with all the rain I have not even had to water it!