Rich writes
I would like to grow some watercress
Don't have stream have a tiny concrete pond about a meter round but
not flowing
Is it possible

Easily

and where do you get seeds or plants?

The supermarket, if you're posting from the UK. I'm pretty sure that's
where I got mine from - IIRC I just threw the bunch in. Pond owners
often do this as a way of keeping algal growth down by removing some of
the nitrogen.

If you're planning to eat the watercress, Google on watercress and
"liver fluke" and take appropriate precautions.
--
Kay