Preserve your natural backyard pond

Having a naturally occurring watering hole or pond is an honor. Ponds provide endless hours of enjoyment from offering a closeness to nature few have. You then ask, “Does it need to be managed?”

Dragonfly near pond | Michigan State University Extension
Dragonfly near pond | Michigan State University Extension

You have a beautiful natural pond. You see a variety of plants and animals and twice a year extra algae. So what is wrong with it again? Someone thinks you have too much algae and plants and suggests that you have to “manage” your pond. Then what follows is lots of helpful advice from a variety of people. Most who are really in the business to sell you a product, they care about your pond but they may care much more about selling you a corrective product. The actual reality is that algae is a normal part of pond life. It comes and goes in the spring and fall naturally due to "turnover". This is normal. No products for management are needed. According to a Michigan State University Extension article, thermocline are the reason for this.

Sometimes there is a lot of algae as a result of nutrient loading and this can cause a pond to take on a green cloudy appearance. If this is happening, you do need to change some shoreline management practices around your pond. Not in the pond as much as on the shore. You may need to mow less! Especially if you are mowing right to the water's edge.

Mowing the lawn right up to the edge of a lake or pond allows for surface water to runoff during a rain event to flow directly into the water. Rain water runoff carries extra nutrients from the soil into the water feeding (fertilizing) the algae every time it rains. If you are fertilizing your lawn near the pond, you are unwittingly magnifying the effect from this practice. I can give you lots of advice about how to manage the algae in your pond but this is becomes meaningless if the root of the cause is not corrected. To use a colloquial phrase, “you have to stop feeding the beast.”

So what are a few first steps to get started?

  1. Create a buffer strip of either grasses or landscape with native plants that will serve as both a buffer and add natural beauty attracting butterflies and birds. You can leave an open space or create paths to the pond edge for access, but the majority of your pond should be shrouded in shrubs, grasses and other water loving plants. This will protect the edge from erosion and stabilize the shore as well as buffer the water from runoff. It will also help reduce the access of geese to your lawn. (Geese don't like tall grasses.)
  2. Do not fertilize within 10’ feet of your pond and use a phosphorous free fertilizer.
  3. It is OK to remove the excess algae with a rake, compost more than 50’ feet away from the water’s edge.
  4. If you remove the nutrient loading problem you will see a reduction in algae growth. However if you are looking for faster results, you can put something in the pond if you want. Blue dyes are the least harmful and deny the blue spectrum light that the plants require, killing the algae and is rated safe for fish and animals. It will turn everything blue and makes it hard to see the fish and frogs. Dyes work best for fountains, garden ponds and ponds that experience an overall pea soup green algae problem. Aerators or floating fountains are also effective helping to stimulate enzyme and other decomposer activity. They come with an initial investment and ongoing electricity cost, and add maintenance.
  5. Or do nothing to your pond beyond adding a buffer strip, and love it in all its natural changes.

Here are some websites for more information:

Landscaping for Water Quality

Managing Michigan Ponds

Pond Ecology - Penn State

Pond and Lake Management - Rutgers

For more information about invasive aquatic plants contact Beth Clawson, MSU Extension Educator. To learn more about invasive organisms and invasive aquatic plants contact Michigan State University Extension Natural Resources educators who are working across Michigan to provide aquatic invasive species educational programming and assistance. You can contact an educator through MSU Extension’s “Find an Expert” search tool using the keywords “Natural Resources Water Quality.”

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