Ponds and other water features are prized throughout landscapes to get the natural appeal they bring to an area and, often, the vegetation and other aquatic life that they support. Although a small amount of algae is usually not considered problematic, higher algae levels can damage aquatic plants, produce an unpleasant scent, clog pumps and create other problems. 1 possible means to effectively prevent an algae problem involves adding barley straw into a pond. The straw releases a natural algaecide since it decomposes.
Placing the barley straw in the pond at the proper time is essential for algae control. When the water temperatures are reduced, or less than approximately 50 degrees Fahrenheit, it can take the barley straw six to eight weeks to decompose enough to effectively control algae growth, however when temperatures are over 68 degrees Fahrenheit that the straw can get successful after just one or two weeks. Noting when algae appeared during past years and timing the implementation of this barley for a few weeks prior to the expected algae development helps to ensure successful algae prevention.
The amount of barley straw needed depends on the pond’s surface area, not its volume. As a rule of thumb, about a half ounce of crust per square yard of surface area is sufficient. Where algae has proved very problematic in previous years or water is quite muddy, a larger amount of barley straw is warranted. An excessive amount of straw, though, can seriously deplete oxygen from the pond, therefore just using the amount of straw required to keep low algae levels is important.
Preparing the Barley Straw
Just dried barley straw can effectively limit algae growth; brand new or ulcerative colitis can actually encourage algae growth and deplete oxygen. Bales of barley straw are broken up so the straw is loose, allowing water to flow through the straw and encourage decomposition. Loose straw is enclosed in some type of mesh bagging like a little onion bag, cotton straps or bird netting. If the water in the pond is any deeper than 4 to 5 feet, also place a float from the mesh bag.
The mesh bag filled with barley straw is attached directly to a cinder block or alternative weight or connected to the weight with a length of rope so the straw remains about 3 to 4 feet under the surface of the water. In small ponds, placing one bag of straw in the center of the pond is sufficient. For larger ponds, splitting the barley straw up and placing it in numerous totes that are scattered across the pond, particularly in warmer water, offers more effective hands. Leaving a rope plus perchance a float at the surface connected to the straw-filled bag allows for easier prevention and later disposal or replacement. Barley straw will stay effective for about six months.