Espoma Organic 4 lb. 3-5-3 Bulb-Tone Bulb Food. This all-natural plant food is specially formulated for bulbs and tubers, containing bone meal and other natural organics to meet their unique nutritional needs. Enhanced with Bio-tone, a proprietary blend of beneficial microbes, Bulb-Tone biologically enhances the natural plant food for superior growth. It feeds slowly and safely, providing a long-lasting food reservoir for exceptional results. Suitable for all bulbs, including tulips, daffodils, crocus, and hyacinths.