Provides important nutrition to aquatic plants for a period of one year. The temperature activated feeding sticks release nutrients only when plants need them most at or above 50° F (10° C). Once activated, the spikes slowly release a well-balanced feeding formula that maximizes the size & color of aquatic plants. With low amounts of phosphorous and no copper, the pond spikes have no adverse effect on water quality and are non-toxic to fish and plant life. Fertilizer Pond Spikes are specifically designed for potted plants and are compatible with all planting baskets. Available in a 6-pack or 3-pack.