What Causes Algae inPonds?

Pondowners often complain about algae. Slimy, green (sometimes brown) residue showsup almost overnight, creating a gross film over the surface of your pond. Thiseasily distracts from the natural beauty of your pond for which you've workedso hard. One thing to remember though is, however unsightly, algae are justlike any other plant in that it requires certain conditions in order to thrive.Three needs must be met for algae to grow at an accelerated rate, so if you wantto control the rate of algae growth, watch for these algae-growing enablers.

Nutrients

Phosphorusand nitrogen can easily be found in koi ponds in both the fish food and in fishwaste. Fertilizer run-off, other animal waste, and dead or decaying leaves andvegetation also lend a hand in providing the nitrogen and phosphorus diet thatalgae needs to bloom.

Sunlight

Thebloom season for algae is the same as probably the rest of the plants in yourgarden – the warmer, sunnier months from April through October. This is becausealgae need sunlight to photosynthesize its food and ponds that sit in directsunlight for most of the day run a higher risk of higher algae content. Fullsunlight aids algae in accelerated growth, which is why algae can seem to be abigger problem than it is.

Low Oxygen Level

Ponds that are stagnant because of waste and nutrientbuild-up generally deplete a pond of oxygen. Dying algae will play a hand infeeding new cycles of living algae because there isn't enough oxygen to bothbreak down the waste in the water and fuel their growth.

All of these things can lead up to excess algae in any pond.Because algae is just another plant, controlling it the natural way is as easyas understanding what enables it best to grow. Once you understand what keyelements aid in algal growth, you can cut algae off at the source and allowyour pond to mesh with the environment, giving it a natural look.