After hearing and reading a variety of things about using Barley Straw for treating algae in ponds we, at the Plant Place, decided to try some in our ponds. At first we were skeptical but decided a new approach was worth a try.
We have a 125 gallon preformed pond, with about 10 inches of soil in the bottom, which we use for propagating and growing one lily species — one that is particularly invasive so we wanted to keep it under control (Charlene Strawn) by confiming it to a container with plenty of room. This pond has no f1ltration, a mosquito fish population, and was planted in early spring with the lilies. We also took the advice in Perry Slocum’s book and sandwiched 10-10-10 fertilizer into the soil before planting the lilies. Of course, with the lilies just breaking dormancy, and no fast growing plants to counter that fertilizer, the pond went to pea soup green within days!
After several weeks of pea soup (which was slowing the lily growth) we decided to try the barley straw. We found some at a local pond shop, 1 small bale, and stuck it in the pond. There is no flow in this pond, as it has no pump, the water was about 5 weeks old, and we just floated the barley bale in the middle of the water. Within 24 hours, the pea soup was gone! Maybe this was an extra potent bale of barley straw, but it really did work.
This barley straw has been moved from growing pond to growing pond, if any of them developed pea soup. The original pond has been without barley for months now and no return of the pea soup algae. The barley has been very effective for us, eliminating pea soup algae within 24-48 hours. The same bale is still in use today (months later). The nice thing about the barley for us is, we can use a water soluble fertilizer in the growing ponds, fertilizing quickly, and counter an algae bloom (if it occurs) with the barley.
Now, we will admit, we are reluctant to leave the barley in any pond for too long. We have to wonder if it is that potent against a plant (algae IS a plant) what will it potentially do to the ornamental plants? When the barley bale was placed in our 700 gallon greenhouse pond, used for tropical lilies, the algae cleared up in a couple of days.
We also noticed that after approximately 3 weeks the lilies were all looking healthy but with no new blooms. We immediately removed the barley bale and within 3 – 4 days new blooms were noticed on the lilies. We cannot scientifically confirm this, but it seemed to us that the barley bale not only stopped the growth of algae, but also hindered the bloom of the lilies in this pond. Now when the barley bale is used, as soon as the algae clears from the pond, the bale is removed.
As of this writing this procedure seems to work for us.
The following is a summary of an article written by Dr. Jonathan Newman, Senior Research Scientist at the Centre of Aquatic Plant Management in England.
The Centre for Aquatic Plant Management (previously the Aquatic Weeds Research Unit) published an information sheet on the practical application of straw. They have been involved in the research on straw for about 15 years. A new method was developed by the Centre for Aquatic Plant Management for controlling algae. It uses barley straw in the water and has been tested in a large variety of conditions. They have documented a high rate of success with no side effects.
What the Straw Does
Putting barley straw into water, starts it to rot. A chemical is released which inhibits the growth of algae. They say it can take about 6-8 weeks for straw to start working at temperatures below 50°f When the water is over 70°f the straw may start working in 1-2 weeks. The straw can function for approximately six months, afterwards gradually decreasing in its effectiveness.
Calculating the Amount of Straw
The Center has found that the most important measurement in calculating the amount of straw is the surface area of the water.
The volume of the water does not seam to have an affect on the efficiency of the straw. This may be because the majority of algae takes place on the surface of the water. For most instances approximately I ounce / 3 sq. ft to 3 1/2 ounces/3 sq. ft. should do the job of controlling algae. After the algae is under control you can reduce the amount of straw in the water and use it to prevent a recuning algae bloom.
How to Use the Straw in garden ponds.
Only a couple of ounces of straw are needed. The straw can be put into a net bag, nylon stocking or tied into a bundle with string. This can be attached to a stone, or brick, to keep the straw in place and dropped into the pond. However, as the straw becomes water logged, it can sink to the bottom, and will not work as well as it does near the surface.
It is advisable to include some form of float in the net, i.e., corks, Styrofoam or small plastic bottles with tops. Some pond supply businesses may have small bales of the barley straw already in netting. Follow the directions supplied with the straw or just anchor and attach to a float as described above.
Source: The following articles are borrowed from the website www.theplantplace.com. A site that I found to be excellent for information on ponding and plant care. Give them a visit!