Few people have visions of dollar signs flashing before their eyes when they see seaweed washed up on a beach, but this rubbery plant is, in fact, quite valuable. Once processed, seaweed is used as a food, a fertilizer, and as an ingredient in cosmetics. (Reference 3) The scale of the seaweed industry varies widely; in poorer countries harvesting and processing is small-scale and done by hand, (Reference 1) while producers in wealthy countries such as Scotland use automated processing facilities. (Reference 2) Processing seaweed is done by carefully drying it; this is easy to do yourself.
Harvest the seaweed from shallow water. This can be done by hand by pulling it up and cutting it at the base.
Set up a raised wooden drying rack. (Reference 1, page 4) A wooden cargo pallet raised up on cinder blocks placed under each corner works well, or you could build a basic rack from spare wood. Allow gaps between the pieces for air to pass through.
Spread the seaweed out in a thin layer on top of the drying rack. Do not pile it up, as this will lead to the buried seaweed rotting. (Reference 1, page 5)
Turn the seaweed over regularly as it dries in the sun. This will dry it more quickly and prevent rot. (Reference 1, page 4)
Cover the seaweed with a plastic sheet during the night and when it rains. This sheet must be raised up to allow air to pass over the seaweed. (Reference 1, page 6) You can raise the sheet by hammering a vertical post made of a stick to the center of your drying rack. This will turn the plastic sheet into a basic tent shape. Pin down the edges of the sheet by nailing them to the sides of the rack.
Pick through the dried seaweed to remove any flotsam or sea creatures that were trapped in it when you harvested it. Good quality seaweed should be clean, dry, and colorful. If it has turned white, this is a sign that it was bleached by too much condensation, or cooked by an improperly vented plastic sheet. (Reference 1, page 9)
Chop up and bag the seaweed for sale, or store it for consumption.