The Hazards of Barley Straw

Use barley straw to treat alagae growth in water.

Barley straw is commonly used to control algae growth in ponds. The straw breaks down and eventually forms hydrogen peroxide. This small level of hydrogen peroxide will inhibit the growth of algae. Research has shown that the proper usage of barley straw is an effective treatment, though there are some circumstances in which hazards can occur if barley straw is not used properly.

Layer Thickness

Barley straw is only effective when the layer on top of the pond is thin. The rotting straw has access to oxygen and can completely break down. If the layers are too thick, then water cannot move through the straw and produce a completely anaerobic environment. This anaerobic decomposition--versus the aerobic decomposition desired--can produce chemicals that actually promote algae growth. Do not worry about the volume of water you are treating. Instead, use the surface area of the water to determine how much straw to use. About 50 grams per square meter is recommended for barley straw treatment.

Aquatic Plants

Barley straw does not control pond weeds and the growth of other aquatic plants. In fact, barley straw can remove so much algae that the water becomes clear and plants grow quickly. This growth may occur so fast that it becomes problematic and additional treatment is needed.

Dead Fish

Barley straw is organic matter and the decaying straw will remove oxygen form the water, which decreases the amount of oxygen available in the water for fish. Therefore, barley straw can promote fish kill if another aeration source is not provided. Decaying fish can promote adverse bacterial growth in the water.

Pesticides

If the barley straw applied to the pond was grown using pesticides, then these pesticides can leech off of the straw and contaminate the pond. Barley straw that is purchased specifically for algae control must be properly labeled, as this assures that there are no pesticides in the straw. Stores cannot legally sell barley straw specifically as algae control as it has not gone through testing by the EPA. Therefore, barley straw can only be used on private ponds and water sources and not on public water.

References

• Healing Rainbows: Clear and Clean Pond Water
• Ohio State University: Algae Control with Barley Straw
• Barley World: Aquatic Plant Management