Fisheries Leaflet No. 1
A GUIDE FOR FERTILIZING FISH PONDS AND LAKES
Wildlife and Freshwater Fishieries Division
Department of Conservation and Natural Resources
To obtain high production of harvestable-sized fish from ponds and lakes, it is necessary that a good fertilization program be practiced each year. Application of fertilizer produces an abundance of plankton algae, aquatic worms, insect larvae and other aquatic organisms which serve as food for fish. In addition to increased production of fish, proper fertilization will also control most types of undesirable aquatic weeds and algae. Fertilizer does not keep fish from biting.
1. Begin fertilization on February 15th of each year (or when the water temperature reaches 60oF).
2. Use per acre for each application one of the following:
a. 40 pounds of 20-20-5.
b. 50 pounds of 16-16-4.
c. Any combination of fertilizer concentrates equivalent to 100 pounds of 8-8-2.
d. *Use per acre for each application one of the following:
1) 40 pounds of superphosphate (18-20%).
2). 18 pounds of triple superphosphate (46-52%).
3). Liquid fertilizer.
3. Make 3 applications at 2-week intervals. Use a fertilizer platform with granular fertilizer if possible.
4. Make additional applications of fertilizer every 3 to 4 weeks, or when the water clears so that you can see deeper than 12-18 inches into the water. Ponds and lakes normally require 10 to 12 applications of fertilizer each year.
5. Discontinue fertilization when water becomes cold in November.
*Research by fisheries biologists of Auburn University and the Alabama Department of Conservation and Natural Resources has revealed that most ponds can be fertilized adequately with phosphate. The use of phosphate should be on a trial basis in each pond. If the use of phosphate does not maintain a desirable growth of plankton or green color, send samples of the pond bottom to the Agronomy and Soils Laboratory, Auburn University, Auburn, Alabama, to determine if the pond should be limed. Sample containers may be obtained from the County Extension Specialist in your county. Until the report is received, fertilize the pond with a complete fertilizer described in 2. a., b., or c.
One fertilizer platform is needed in ponds ten surface acres or larger. One platform can disperse granular fertilizer for up to 25 surface acres of water if the platform is 3-1/2 square feet for each surface acre of water.