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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 of sunlight
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. |