Guanos have been used for centuries as fertilizers for all kinds of plants. Happy Frog® Cavern Culture® Fertilizer is a proprietary blend of bat and seabird guano, rock phosphate and soil microbes that is specially formulated to deliver the nutrition necessary for flowering and bud development. Mycorrhizal fungi are included to help increase root efficiency, which may enhance nutrient uptake and water absorption. Experience the tried-and-true successes of our ancestors with Cavern Culture® in your own backyard. OMRI Listed® and Registered CDFA Organic Input Material.