Thanks everyone, being new to this I just didn't know whether it was indeed an established practice or not. I know a lot of people use the seaweed for fertilizer for general gardening use and I read about the liquid seaweed specifically for orchid. so since I'd been seeing a lot of it on the beaches recently, I began to wonder.
I don't know about its plant uses but if it is picked fresh then it isn't salty once rinsed- apparently it even tastes like lettuce! I would love to know how this works out for you!!