Pond Scum. Green Slime. Mosquito-Breeding Muck.
Nobody likes a pond covered with algae. Algae can be beneficial, but that all-encompassing, gooey mess is too much. That pond scum is a smothering blanket that blocks light and kills plants and fish. Why do some ponds turn into scum pits, while others have minimal algae growth? As a pond owner or someone living near a pond, what can you do to prevent it?
Algae grows in stagnantwaters. It loves direct sunlight and nutrients. You can discourage algae growth by adding oxygen to your pond and reducing exposure to the phosphates and nitrogen found in fertilizers. Here are some steps you can take:
- Aerate! Bubbling aerators and fountains keep the water moving and add oxygen to ponds. Higher oxygen levels reduce algae growth.
- Add plants! Plants add oxygen. They also use some of those nutrients that contribute to excessive algae growth. Pond plants can improve a pond’s aesthetics while keeping the water clear. Your best sources of information on plants are local nurseries and garden centers that specialize in ponds and wetlands plantings. Be aware that ponds located near tidal water may contain salt or brackish water. If that is the case, opt for salt-tolerant species.
- Treat if you must, but use an environmentally friendly algaecide. Do not grab the stuff you would use in a swimming pool. Use only the amount recommended.
Now for the really important step: Reduce the fertilizer! If you use too much, you are fertilizing the algae. If you feed it, scum will grow. Use a nutrient management plan. That means that you should have your soil tested before using fertilizer. That way you can limit fertilizer use to what your soil needs. Extra fertilizer is not absorbed by your plants…it runs downstream. Also, avoid fertilizing near a drainage system and watch the weather! You don’t want to fertilize just before a rain storm.
Following these steps will keep your fertilizer and your landscaping dollars from washing away. In addition to the money-saving benefits, reducing algae makes ponds look better. It also helps the environment.