How Can I Prevent Pond Algae?

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Not all algae is bad First, let's get our minds wrapped around this: Not all algea in ponds and lakes is bad. The problem comes when you have too much algae, or the wrong type of algae. In fact, the best treatment for pond algae, is algae! I know it sounds a little strange, but that is the way it works. What is pond algae When most people think of pond algae, they think of the type of algae commonly called pond scum, or blanket weed. The proper name for it is fillamentous algae. This is a type of algae that forms long fillaments or strings that then mat together to form a blanket on the surface of the water. This mat or blanket of algae makes fishing, boating, and other recreational use of a lake or pond difficult and distastefull. Pond scum also allows a perfect environment for mosquito production. In general, blanket weed in a lake is not a good thing for human use and interaction with the lake. Understanding pond algae To understand the best treatment for it, we need to understand where it starts, and how it starts. When we notice pond scum, we notice it on the top of the water, but that is not where it begins. Fillamentous algae starts at the bottom of your reservoir, and rises through the water profile as it gains bouyancy from the oxygen it produces. Eventually, enough oxygen is produced to lift it to the top of the water where it floats annoyingly. Clear water is the problem The problem is not that your pond or lake water is too murky, the proble m is that it is too clear. Again, I know that this is counter intuative, but bare with me. You have probably heard someone say "I can't see through muddy water." when they wanted you to move out of their line of site. The same principle applies here, because light penetrates straight through clear water, and because sunlight is needed for plant production, if the water is not clear, plant production is limited. If your water is too clear, you will have pond algae. The answer is not to go out and make the water muddy, the answer is to produce a single cell algae known as phytoplankton to tint the water, and prevent sunlight from reaching the bottom. So how do we prevent pond algae? Pond fertility is the answer. Check your pond or lakes water. If it is clear to a depth of more than 20 inches or so, it is too clear, and chances are, your fish are going hungry as well. A good fertilization program will solve both problems, and many others as well. This is how it works: When the proper amount of the proper fertilizer is introduced into the water, in the proper way, the single cell algae known as phytoplankton will reproduce rapidly in a process called algae bloom. This will continue as long as the water is fertile. The green color, or the golden brown coloring that this method produces will tint the water, preventing sunlight penetration, and preventing the growth of fillamentous algae. To learn how to do this see these pages, How To Fertilize A Pond Or Lake Lake Fertilization Lake Management Lake Weed Control Water Depth Secchi Depth and all the posts in this section of Home And Garden Press: Lake Management

Barley Straw Pond Algae Control: How To


Barley straw can be an effective treatment for the prevention of blanket weed pond scum, pond algae, but there are a few caveats and precautions to keep in mind. Barley straw pond algae control is not always the best method of pond algae control. Read the list of precautions, and decide for yourself. Instructions on the use of barley straw pond algae control, including the proper methods are given below.

Barley straw will not:

  • Eliminate existing pond scum
  • Work in muddy water
  • Work in water with low oxygen
  • Work only against bad pond algae production

Barley straw will:

  • Decompose, adding nutrients to the water
  • Use oxygen during decomposition
  • Kill all forms of algae, including phytoplankton
Barley straw only works to prevent pond algae, not to kill it, and will not work in certain conditions like muddy water and low oxygen. It will decompose and use oxygen during the process which can be fatal to fish if too much decomposition occurs too quickly. Decomposition also produces nitrogen which can act as a fertilizer for future weeds and algae production, which will increase in the newly cleared water. Barley straw will decrease phytoplankton production resulting in water clarity, and a lack of food for fish as well as allowing sunlight to penetrate to the bottom, which can result in more pond algae and lake weed production after the barley is gone. A proper fertility program to promote the growth of phytoplankton should be put in place to prevent such an outcome. Once a good fertility program is in place and ongoing, the need for any pond algae treatment will evaporate in most cases.
With all of these possibilities in mind, this is the process you can use to apply barley straw to a pond or lake for the treatment of pond algae:

Amount of barley straw to use

If pond scum is a recurring problem, 100, to 250 pounds of barley straw per surface acres can be used for preventing unwanted lake algae. A surface acre, is 43,560 square feet. To determine the size of your pond or lakes surface area, multiply the number of feet from side to side, with the number of feet end to end. The numbers do not have to be precise, just as close as possible. If the ends or sides are not equal distances, simply average the distance of both sides, and the distance of both ends before multiplying. This should be close enough for a barley straw treatment.

How to apply barley straw

Separate the barley into equal units, and place it in weighted mesh bags, rolls of hardware cloth, or cages, and sink them around the pond. A string or rope tied to the bags and a stake will help in retrieval. 50 pound onion bags or gunny sacks work well, you can stuff about 6 to 8 pounds of barley straw in an onion bag or gunny sack.

Where to place barley straw

Barley straw will only be effective in oxygenated water, which limits placement to the edges and close to the surface, so do not submerge the straw more than a few inches below the surface or it will simply rot without producing the desired effect. See also: Using Barley Straw As A Blanket Weed Treatment and Barley Straw Pond Algae Treatment Drawbacks