Pond liming is essential maintenance for ponds and lakes with aquatic life because it maintains the alkalinity and pH at levels that are optimal for fish health and a thriving food chain. Ponds with low alkalinity are subject to wider swings in pH throughout the day, which is stressful to fish. Ponds with alkalinity below 20 parts per million typically do not respond to fertilization, which in turn severely limits the food chain of the pond and therefore the pond’s overall carrying capacity.
The average pH of rainfall in the U.S. is below 5, which is highly acidic. As a result, ponds that are not fed by springs or streams tend to become acidic over time. pH below 5.5 severely limits the survival of the eggs and fry of most freshwater species including largemouth bass and bluegill; low pH and low alkalinity both lead to increased susceptibility to disease for most freshwater fish species. We have seen dramatic turnarounds in the fish populations of private ponds and lakes many times just from the application of pond liming. This one substance can make the difference between an ailing pond and a healthy one.
Pond liming is also a valuable tool in clearing turbid water. Because bluegill and largemouth are sight feeders, they typically do not grow well in muddy water; clay turbidity can short-circuit the entire ecosystem of a pond. Ag lime can take a pond from looking like chocolate milk to that perfect deep green color in a matter of days.
Agricultural lime should be applied at a rate of two to six tons per acre depending on how low the alkalinity is at the time of application. The best way to apply lime to ponds already containing water is by use of what is known as a lime barge, which employs a high-pressure sprayer to disperse the lime evenly throughout the pond.
Monthly pond fertilization is a key component of successful management of fish ponds in the South. Pond fertilization is simply feeding the phytoplankton, the microscopic plants found in any pond, so that they greatly increase, creating what is known as a plankton bloom. This bloom provides two major benefits: it prevents sunlight from reaching the pond bottom, thereby short-circuiting the photosynthesis of most aquatic vegetation which begins its life on the bottom; and it turbo-charges the natural food chain of the pond, allowing the pond to support two to four times more fish than it could unfertilized. Regular fertilization is recommended as a primary management technique for private ponds and lakes by the DNRs of every southern state including TWRA.
Phytoplankton are the foundation of the food chain in a pond; so when their numbers greatly increase, so do the numbers of zooplankton that feed on them, as do the numbers of invertebrates that make their home in the pond, as do the small fish that eat the invertebrates…Simply put, in a properly-managed pond, fertilization will allow more quality-sized fish to be produced.
Fertilization is not right for all ponds. If you have an older pond that has a heavy build-up of muck on the bottom and you’re already experiencing significant weed problems, fertilization could potentially make said problems worse. Very shallow ponds with a large amount of water shallower than three feet deep are often not good candidates for fertilization, as the shallow areas can be more prone to excess weed growth.
Pond fertilization becomes more and more crucial as the size of the water body increases. Ponds under two acres in size can often be managed very effectively without fertilization by relying on supplemental feeding; but feeding can become cost-prohibitive on large lakes of fifty acres or more, and on these lakes fertilization can be a real game-changer. When feeding and fertilization are used in concert, fish can be grown at astounding rates.
Southern ponds should be fertilized twice a month in early spring, beginning in February or March depending on weather, and once monthly thereafter through September. Trophy Pond offers monthly pond fertilization as a service for ponds and lakes in middle Tennessee, northern Alabama, and southwestern Kentucky.