Algae are very sensitive to outside factors, like temperature and chemicals, and can outgrow, suffocate, or even poison other organisms when the algae growth suddenly takes off in what is called an algae bloom. Fortunately, there are several ways to manage algae and keep your ponds healthy.
Many people use chemicals to manage algae. Copper has been used for many years as a chemical tool in freshwater farm ponds and aquaculture operations. It is both an effective algicide and a parasite treatment. The problem with the use of copper is that there is a thin line that separates effective treatment levels from overdoses, which can kill fish. Insects, snails, frogs, and fish can all be killed by algaecides if they are too concentrated. These creatures are all part of a healthy ecosystem and help keep algae in check naturally. If they are killed along with the algae, the next generation of algae will return even stronger. http://edis.ifas.ufl.edu/fa008 for more information.
One of the most benign tools for algae management is pond dye. As the name implies it is a vegetable based dye that blocks some of the ultraviolet light that stimulates algae growth. The shade from pond dye reduces algae growth and underwater (submerged) plant growth.
Barley Straw is a natural alternative in decorative garden and fish ponds. A clear netting holds the barley together without detracting from or harming the pond plants and fish. When barley straw is put into water, its cellular structure starts to break down or decompose. A microbial activity process drives this breakdown or decomposition. It is during this process that chemicals are released which inhibit the growth of algae.
Another option is to physically remove algae from the water. For smaller ponds, you can pull on your boots and manually collect algae into buckets. For larger ponds, you may want to use special equipment designed for collecting algae. Although the process is labor-intensive it has proven to be effective. You will also have the added benefit of no chemicals in your pond and less nutrients for future algae.
If harvesting sounds like a hassle, then adding more plants to your pond may be the way you should go. Encouraging aquatic wildflowers in and around a pond is actually one of the best ways to manage algae. Plants like water lilies help shade the pond, dropping the water temperature and slowing algae growth. Submerged aquatic plants like pond grasses will compete with the algae for light and nutrients. When both types of plants are used together, algae growth can be substantially reduced. Also, aquatic plants provide homes for dragonflies and frogs, and many have colorful blooms that attract butterflies. For those of you who enjoy gardening, this is a great opportunity to expand your gardening repertoire.
Although you use fertilizers to encourage plant growth on land, you may also be fertilizing the algae in your pond. Algae are VERY sensitive to fertilizers. In fact, run-off loaded with fertilizers may be one of the leading causes of algae blooms in ponds. Implementing sustainable landscapes and practices on your land will go far in managing algae. Here are a few tips to help get you started.
- Keep fertilizer at least 10 feet away from water.
- Keep fertilizer away from any paved surface so that it won’t be washed down roads or drains into storm water ponds.
- Keep grass clippings out of ponds. Clippings, like
fertilizers, are high in the nitrogen.