You must have BUSH and WATER BUCKET to make SEAWEED. SEAWEED belongs to face category. Lunch brake plant. Not for speed eaters though. Want 5 experinece points? Brake SEAWEED block or tree. SEAWEED can be broken. Seed mathematics is very complicated, but you should get at least 1 seed back from splicing SEAWEED. Will you strike it rich? You just have to count the gems yourself. Massproducing SEAWEED can be tricky. You will find out after you have harvested a few.