We have a lot of residential subdivisions with ponds on them. We have a lot of farmsteads with ponds. If you have a pond, either your own private pond or one owned and managed by your homeowner’s association, now is the time to start planning for next year’s management of the pond.
I get several calls every July and August asking how to control the algae bloom choking the pond or what to do to stop a sudden fish kill in the pond. The answer is, not much. You missed your chance to largely and cheaply avoid this problem in July by not planning in January. So plan now, unless you also plan to wait until you apply for Social Security to plan for your retirement. The results in both cases are easily predictable.
Once you know how a pond works, it is easy to manage. The easiest ponds to manage are fertilized sport-fishing ponds. Around here that means bluegill, bass, catfish and a few triploid carp.
The pond’s ecosystem starts with the phytoplankton bloom. The phytoplankton are not algae, which is what you get when you don’t get the phytoplankton off to a good start.
As soon as the surface-water temperature consistently holds 60 degrees, you start fertilizing the pond with 40 pounds of a 20-20-5 granular fertilizer per surface-acre of pond. We are trying to get the phytoplankton population to bloom early in the year in the top 18 inches of the pond water. Don’t spread the fertilizer across the pond surface because the granules will just sink to the bottom and be lost. We open the flat side of a bag of 20-20-5 granular fertilizer by cutting an H into the top flat surface of the bag and gently lowering it into the edge of the pond just deep enough to cover the bag. Pull the two center panels open and there you have it.
Keep adding fertilizer the same way every two weeks until the proper color develops. Space the bags around the perimeter of the pond to get as even a supply of fertilizer into the top 18 inches of water as possible. The proper color is reached when a shiny object lowered 18 inches into the pond cannot be seen.
If the proper color has not developed within six weeks, have the pond checked for water hardness. Water that is too soft will not support the phytoplankton.
The phytoplankton do a number of good things for your pond. They produce most of the oxygen the fish breathe and are the start of the food chain in the lake. They shade the water, and cooler water holds more oxygen than warmer water, which supports more fish. Shaded water does not allow enough light for immersed weeds to grow.
The phytoplankton also tend to out-compete the filamentous algae. Properly started, weed management in a pond can be easily done with triploid (grass) carp instead of expensive herbicide chemistry. Keep fertilizing throughout the summer to maintain the right color. If shiny objects disappear at a 12-inch depth, stop fertilizing until the shiny object is again visible deeper than 18 inches.
There are other issues, like fish-species balance, to monitor and manage, but the good news is a fertilized pond usually produces 400 percent more pounds of fish each year than an unfertilized pond. That also means you have to take fish out of the pond to keep the pond balanced.
Working to make a pond balanced and productive is useless if you do not harvest fish in the proper sizes and quantities. If you leave too many large predator bass in the pond, they not only will eat the brim but also the smaller bass, leaving you with a few hungry lunkers and a need to harvest them and restock.
Paying attention to the pond and managing it properly leads to maximum fish at the lowest cost. The first step to that 6-pounder is fertilizer in February.