As you think about winterizing your property, don't overlook the farm pond. Winter can be the perfect time to set the stage for your spring fertility program and to get a step ahead of weeds. And contrary to what you may have heard, winter is not the time to stop feeding fish accustomed to the practice.
Cooler water absorbs more oxygen during winter months. Fish, being cold-blooded animals, drop their metabolism during this season, decreasing their use of the now-abundant oxygen. The fish also decrease feeding significantly but not completely. While it is true that overfeeding during the winter can lead to season-long pond problems, simply think of this as an optimal time to adjust your feeding practices.
Billy Higginbotham, a fisheries expert with the Texas Cooperative Extension Service, recommends significantly cutting back on feed. He suggests opting for a floating feed that will not fall to the bottom of the pond and decay.
"Feeding in the winter requires that you choose a warm, sunny afternoon, and then offer only a little floating feed to the fish. Give them only what they will eat in a short period of time. Do this once a week, or even every other week," Higginbotham advises. "This will allow fish to go into the spring in better condition, but it won't create water-quality problems down the road."
If your pond is self-sustaining—you don't give your fish supplemental feed—winter is not the time to begin feeding fish. They aren't accustomed to being fed and simply won't respond to winter feeding.
Water quality. Winter is the best time to fine-tune your pond's water quality. A water-quality test is the first step. This shows pH and total alkalinity levels. Test kits are available at pond supply stores and co-ops. Your county Extension agent also can help with the process.
Total alkalinity is the test to pay the closest attention to, says Higginbotham. This test determines any lime requirements your pond has. He adds that pH levels in water can change over the course of a day. But levels should fall in the 6.5 to 9.0 range. Rely on total alkalinity readings, however, when deciding whether a lime application is really needed for your pond.
"Basically, I tell people if you need lime on your cropland, you probably need it in your farm pond too," says Higginbotham. "But the only way to know for sure is to test the water."
Any total alkalinity reading below 20 parts per million indicates a need for lime. A rule of thumb is any reading of 16 to 20 ppm requires you to add a minimum of 1 ton of agricultural limestone per surface acre of water. If the reading is 10 to 15 ppm, add a minimum of 2 tons. Add 3 tons if it's 5 to 10 ppm.
"These are all minimums," Higginbotham stresses. "The nice thing about agricultural limestone is that it becomes insoluble once the pH is above 8.3. So, what you don't need just sits there and won't go into solution until the pH drops below that 8.3 level. You won't hurt a thing by adding more, in other words."
Applying lime to get the most benefit requires spreading it evenly over the water. If that's not possible, have the lime truck back up to numerous locations around the pond. If this won't work, dump the lime where the water comes into the pond. Correcting pond pH in the winter means fertility programs in the spring will be optimal.
Weed control. If you had weed problems before winter hit, be assured those problems will reappear in the spring. Higginbotham says now is the best time to get a plan of action in place to keep weeds down. He advises getting identification established on the weeds. The next step is to make decisions about how best to control them in the growing season.
Control options for weeds can be biological, mechanical or chemical. Pond owners in many states can use the triploid grass carp to keep down some species of plants and mosses. The fish are considered "exotic" in some areas, like Texas, and can only be purchased through specialty fish farms with an exotic species permit. Landowners who want to add the carp to their ponds also may be required to have a permit.
Mechanical controls are often one of the simplest ways to keep pond vegetation down. Large weed harvesters are available for big lakes, and simple seines can do the job in small home ponds.
Lastly, chemical controls can be very effective. The key is choosing the right herbicide. This means you must know which weeds you need to control. There is a web site that provides photos, descriptions and controls for 50 common weeds found in farm ponds. The web site is through Texas A&M and is found at http://aquaplant.tamu.edu/.