April 2006
Tips on Starting Your Pond Fertilization Early

Would you rather apply 200 pounds of granular 20-20-5 or just 25 pounds of Perfect Pond Plus to your 5-acre lake? New concentrated pond fertilizer is so easy to use! by Don C. Keller Fertilization has been the foundation of most successful pond management programs throughout the southeast and other areas of the United States. Most pond owners know that they should fertilize, but they are not quite sure when to start, how much to use or what type of fertilizer will be best for their ponds. Regular applications of special farm pond fertilizers, from early March through October, produce microscopic aquatic plants, called phytoplankton, that are the basis of the food chain. Proper fertilization programs can increase total fish production by 300 to 400 percent. There are basically three types of farm pond fertilizers – granular, liquid and the new concentrated, water-soluble powdered or crystalline form. Granular farm pond fertilizer is usually a 20-20-5 mixture (n-p-k) and requires 40 pounds per surface acre. Do not spread this over your pond like you would fertilize your lawn, this has to be on a platform or it will not dissolve properly.   Apply only 5 pounds per acre of concentrated, water-soluble, powdered Perfect Pond Plus for each application. Fertilizing should begin in March and continue through October.   The liquid is usually a 10-38-0 mixture and has to be mixed with water before applying to your lake. It weighs almost 13 pounds per gallon and a five-gallon bucket weighs 65 pounds. It is hard to handle and often very messy. Powdered fertilizer, such as Biologic’s Perfect Pond Plus (12-48-8), requires only 5 to 8 pounds per acre and does not have to be mixed with water or placed on a platform. Simply throw the appropriate amount into the lake with a scoop or pour from the side of a moving boat. This is the easiest type of fertilizer to use and is very effective in developing and maintaining a plankton bloom. Just as important as knowing when to fertilize your pond and what to use, is knowing when not to fertilize. There is a lot of misinformation regarding fertilizer, such as: "Fertilizing will make the fish quit biting for a month," or "Fish don’t taste good out of a fertilized pond," and "Fertilizer kills the weeds in your pond." Not one of these old sayings is true, but none can be as potentially devastating as the one about fertilizer killing weeds. Each spring we receive numerous calls about pond weeds which all begin the same way: "I have fertilized three times this spring and the weeds just seem to be growing," the pond owner will say. "Maybe we started fertilizing a little late this year," the owner will continue. If you fertilize once weeds are present, it is like adding gasoline to a small fire, it can quickly get out of control. Do you use fertilizer to kill weeds in your garden or lawn? I doubt you do. The more you fertilize weeds and algae in your pond, the more they grow! Why did anyone ever think that fertilizer would kill weeds? If used properly, pond fertilizer will create a green color (plankton bloom) that will shade the bottom and prevent the penetration of sunlight, thus inhibiting the growth of plants and algae from the bottom. This statement became misinterpreted over the years to make people think that fertilizer kills weeds. Inspect your pond in mid-February and early March for signs of rooted aquatic plants or filamentous algae. Often your pond will be very clear in the winter, allowing sunlight to penetrate to depths of 3 feet or more. This often invites the production of winter filamentous algae. Look around the pond margins and in the shallow coves or the upper end of the pond. Try throwing a deep-diving crankbait to sample the bottom for weed or algal growth. Do not fertilize if weeds or algae are present! Contact a fisheries biologist or an aquatic-weed specialist to identify the plant and provide control options. Control the growth of the weeds or algae before beginning a fertilization program. The new powdered (crystalline) water-soluble fertilizer, such as Biologic’s Perfect Pond Plus, is the preferred fertilizer for today’s pond owners. An application rate of 5 pounds per surface acre will maintain a good bloom. Fertilize approximately once a month or when the water visibility exceeds 18 to 20 inches. For small ponds, you do not have to walk around the pond, simply apply from one location with the wind at your back. Fertilization could not be easier! Keep your fertilization program going; just do not feed the weeds! Don C. Keller is a Certified Fisheries Scientist and co-owner of American Sport Fish Hatchery in Montgomery, Ala. He can be contacted at 334-281-7703 or This e-mail address is being protected from spambots, you need JavaScript enabled to view it .