5 lb bag. Kelp Meal is an all-natural, 100% organic fertilizer made from dried ocean seaweed. Full of beneficial vitamins and mineral, this all-purpose soil treatment works great on potassium loving plants such as lettuce and potatoes. Over 70 vitamins and minerals in one easy to apply treatment. If you’re like most growers, you know the benefits of properly fertilized plants and flowers. It’s no secret that a garden is only as good as the soil it’s grown in. And while most soils can grow plants, many lack the balanced nutrients necessary for growing great plants.