Roots Organic Extreme Serene organic liquid kelp extract is a natural source of growth promoting compounds. Marine kelp has some of the fastest growth of any plant on the planet and they capture that power in an easy to use liquid. Specifically targeted to encourage vigorous growth, Extreme Sereneis a distinctive blend of amazing plant extracts for the hobbyist and professional gardener. It can be used with any nutrient program or as a foliar feed. Great for both soil and hydroponics!