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 we have captured that power for you in an easy to use form. Roots Organics Extreme Serene kelp extract can be used in conjunction with any soil or hydroponic nutrient program. Extreme Serene is especially effective when used as a foliar feed.