Summer Ponderings
by Ken Schoen

If you already read Part One of this series, welcome back! If you missed it, you can find it online at the AboutTown website under “articles/spring10.” In our spring article, it was time to plan or start to build your new pond, or to “awaken” your existing pond. Summer is now here, so let’s turn our attention towards spreading plants, hungry fish, and green water.

Backyard Ponds
With summer warmth, your plants should be starting to flourish. Free floating plants like water hyacinths and water lettuce can actually start to spread so fast that they can take over your small backyard pond (these plants should not be used in natural or larger ponds). Don’t cover more than 50 percent of your surface area. Use the extras for compost or donate to needy pond friends (ask first, don’t just deliver them!) Water lilies and lotus should be fertilized monthly to achieve the best results.

Your fish get hungrier as the water temperature rises... unless it becomes too hot, which makes them want to eat less. If the water temperature goes above 85, feed sparingly, and only in the morning or evening, when water temperatures are cooler. In the spring you should usually feed them a few times a week, up to once a day. In summer you could feed them two or three times a day. Now I’m not saying this is absolutely necessary, just that your fish can handle more food. We have plenty of customers that are around only on weekends that have big, healthy koi. Automatic feeders are also available.

Aeration is always a good idea, especially for any backyard pond with larger koi, which need more oxygen. If you see your fish “gasping” at the water surface or hanging out near the waterfall, they probably need more oxygen. The warmer the water, the less oxygen it can hold. Waterfalls are not the most efficient aeration systems, but are much better than nothing. I know some people who set a timer to turn their waterfall off at night. Don’t. Actually if you are going to set a timer (which I do not recommend), it’s more important for the fish that the waterfall be on at night than during the day. Because of the photosynthesis cycle, plants and even algae contribute to the oxygen level during the day, but are using it up at night.

If your water is too green in a backyard pond, water lilies and floating plants can help shield part of the pond from the sun, while underwater or oxygenating plants can help use up the nutrients that are feeding the green water, which is actually microscopic algae. You could also consider a UV filter, which should be sized not just based on the size of the pond, but also on the amount of sun it receives. Filters work almost like magic. I once installed a very large one on a 40,000 gallon, 70 foot long liner pond. In three days it turned the bright green water “gin clear” (as we say in the trade). The owner accused me of adding chemicals and was worried about his koi (some of which were two feet long and would keep eye contact with you while eating out of your hand). One trick to pond UVs is to change the bulbs at least every two years. Even if the bulb hasn’t burned out, the wavelength will have shortened by then and will prove ineffective.

Larger Ponds
Much of what’s true for the smaller backyard ponds can also apply to the big boys. Forget about UV filters, but aeration can make a big difference. If there’s no electricity right near the pond, the aeration unit can be located even a thousand feet away from the pond with only a small, shallowly buried air line running to the pond itself. For ponds in the real boondocks, highly efficient systems can actually use solar power, even here in the Northeast. I get a lot of calls during the summer about water levels dropping and ponds that don’t look as good as they do in spring and fall. Creative edge work with rocks, plantings and even waterfalls can help the lower water levels still look attractive.

Ken Schoen (www.koiponds.com) has been specializing in ponds and other water features in the Hudson Valley and beyond for over 20 years. If you have a pond question, please email him at pondbuilder@verizon.net or mail it to Waterscapes, 155 Washington Ave, Kingston, NY 12401 and he’ll try to answer it.