Ground kelp is required for the Freeing Pirate Pete subquest of the Recipe for Disaster quest. It is made by using kelp with a pestle and mortar, which awards the player with 1 Cooking experience, and is an ingredient in fish cakes. This item can be obtained by retrieving all the required swimwear items from Murphy and talking to him about diving. He will take the player out in the ocean, where there will be long strands of kelp that can be picked.
Template:Recipe for Disaster - Freeing Pirate Pete