Controlling Algae with BARLEY STRAW By: Greg Smith, ECCD

Do you have problems with algae in your pond? The principal type of algae that cause "summer kills" are plankton algae. These single cell or chain-like groups of cells are free floating and green, blue-green or brown. They commonly appear as small specks or "grass clippings". As the number of algae increases, clumps form and plants die, using up large quantities of oxygen during a time when the pond can least afford it. A large algae bloom die-off depletes oxygen in the water and can cause major fish kills. There is now an effective way to control algae without using dangerous chemicals. An interesting, effective, inexpensive, and environmentally sound method of safely controlling algae is the use of barley straw.

A loose bundle of barley straw is put into a net bag, mesh, or any other open container and placed in an area where the water is the most oxygenated, such as an inlet, fountain or aerator. Fish and other aquatic life need oxygen, and adding a lot of carbon based material (such as grass, barley or leaves) can actually reduce oxygen in the water as it decomposes, so you do not want to use excessive amounts. The barley (in its open container) is anchored (a brick or stone) and floats near the water's surface (may require Styrofoam or other float) where oxygen content is higher, more sunlight is available, and the algae is located. One application lasts about six months.
 

Barley straw has not shown itself to have any negative effects on aquatic plants or animals. In fact, insects and microorganisms live in the hay and provide food for higher animals, and aquatic plants grow better without algae competing for sunlight. Temperature is a major factor. In cold water, the straw may take 3 months or more to be effective. In warm water (70 degrees F or more), it may only take one month.
 

There is no scientific consensus on how barley straw works. The leading theories relate to the byproducts of decomposing lignins. The mystery adds to barley straw’s mystique. The right amounts to use may take some experimentation. Depending on the conditions of your pond and the size, it is likely that you will need only a couple of bales which can be purchased for a total of less than $30 from sources such as Blue Seal Feeds. The best times to put the straw out are in early spring before algae gets started and again in early fall. After you add the new batch, leave the previous batch of straw in for a month or so before removing it since it can take a few months for a new batch to produce algae inhibitors.