Roots Organics Extreme Serene (022) organic liquid nutrient kelp extract is a natural source of growth with compounds specifically targeted to encourage vigorous growth. Roots Organics Extreme Serene is a distinctive blend of amazing plant extracts for the home and professional gardener. Marine kelp has some of the fastest growth of any plant on earth and is now in this easy-to-use form. Roots Organics Extreme Serene kelp extract can be used in conjunction with any potting soil or hydroponic nutrient program. Extreme Serene is especially effective when used as a foliar feed.