Seaweed and Kelp extracts are the most important additives after the general hydroponic nutrients. These extracts are great for boosting the immunity of the plants with the natural antibiotics found in kelp. Seaweed and kelp also enable the plants to take up more nutrients from your nutrient solution. The carbohydrates in seaweed also help increase the yield and quality of your plants.
Seaweed for plants comes highly concentrated and is used by adding it to water with other nutrients, if necessary, and then watering through the soil or growing media.