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Barley Straw Algae Control

Algae Bloom in a pond with loose rock & gravel on the floor of the pond

"String" Algae

  If you have large amounts of string algae in your pond, such as shown,
it is best to remove it by hand prior to treating your pond.

See also:  "Managing Problems of 'Loose Rock' Style of Pondbuilding"

How to measure the gallonage of your pond

"Bag O' Barley"- 100% Certified Barley Straw
SDSU Seed Testing Certification # HF-2345-B

Non Toxic  Biodegradable  Environmentally Friendly

 S636  Bag O' Barley (3) 4oz. bags; treats 1500 gal. 21.00 [Buy]
 S638  Bag O' Barley (3) 8 oz. bags; treats 3000 gal. 41.00 [Buy]
 S639  Bag O' Barley 2 lb. bag; treats 4000 gal.
    Approximate size per bag: 9" x 14" x 18"
41.00 [Buy]

"The safe and organic approach to a crystal clean pond"

You should apply barley straw in the early spring prior to the growing season and into the fall to protect your pond over the winter months.

Bag O' Barley is loosely packed for the best flow of water possible, and therefore the best results for the pond owner.


Remove mesh- filled bag from outer wrap. Place bag in return portion of the bio-filter and/or anywhere in the pond where good water flow and current occur. Sunlight and water flow are crucial elements in the decomposition process. Make sure you use both elements in choosing the location for your bag(s) to be placed.

Float on the water's surface, or weight down underwater (using a rock). Barley straw should be used in conjunction with an adequate mechanical / biological filtration system.

If you have large amounts of string algae in your pond, remove it by hand prior to treating your pond.

Always have multiple bags decomposing to insure the highest level of barley bacteria possible. Place bag(s) in desired area - two to three weeks later place a second bag(s) in desired area - two to three weeks later replace the first bag(s) with a new bag(s). Continue this alternating process every three weeks throughout your ponding season, ensuring you will always have decomposing barley bacteria.

How Barley Straw Works to Control String Algae

Water gardens and small ponds tend to be especially susceptible to water quality problems. They are shallow and warm, often low in oxygen, and are usually in a landscaped setting where fertilizers and organic materials run off and settle in the pond. The result is a water feature, intended to be beautiful and soothing, that is lost to the high maintenance required to keep it clean. Finally, the pond owner resorts to expensive, short-lived chemical treatments in the hopes of seeing that prized koi, hiding just inches below the surface.

Today's alternative, barley straw, offers the pond owner a safe and effective, inexpensive, and long-term solution to string algae control. The pond owner places a small bag of barley straw at the surface and lets nature do the work. When properly applied, naturally occurring microorganisms decompose the lignins in the barley, releasing humic substances (dissolved organic carbon) in the water. In the presence ofsunlight and oxygen, these compounds are converted into low levels of hydrogen peroxide. The hydrogen peroxide is the component that modifies the pond chemistry to improve pond clarity. Hydrogen peroxide itself is relatively unstable and does not persist in water, but the slow release effect from the barley straw provides a constant source of hydrogen peroxide. The effects from barley straw will begin as early as one to two weeks after installation, and will remain effective for between four and six months.

Tips for Success:

Apply early in the spring (March or April) before algae and turbidity increase.
Physically remove existing algae at the time of installation.
Float the barley at the surface for best exposure to oxygen.
Aerate the water.
Place the barley near a waterfall or aerator.
Use smaller. more frequent applications in warmer climates.
Apply a second treatment prior to total decomposition of the first. Also, leave the first application in the water for at least two to three weeks beyond application of the second treatment.

Recommended application rates are based on results as observed at the Centre for Aquatic Plant Management in the United Kingdom. Performance may vary by climate, typically with more frequent smaller doses recommended in warmer climates. Increase the dosage in waters that are turbid or muddy. Results may vary and it is better to apply too much straw in the first application and gradually reduce the dose to an effective maintenance dose.

Effects on other organisms in the pond:

No harmful effects on vascular aquatic plants, invertebrates, or higher animals has been observed in laboratory or field testing. On the contrary, some studies show improved growth of invertebrates, in turn providing prey for fish and waterfowl.

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