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 The Seven Deadly Sins
of Pond-keeping

By Greg Speichert
Originally published in Water Gardening Magazine, May/June 1998  
Reprinted with permission by


1. Making the pond too small, too shallow, or too deep.
Many first-time pond builders do not realize how many gallons it takes to make up a square foot of water. Two hundred fifty gallons sounds like a lot at first, but it is only enough to fill an area about 4 foot square and 2 feet deep. The best rule of thumb is to make the pond as large as you can for the space where you want it to go. If you really do want to start out small with an in-ground pond, then line the pond with EPDM rubber liner, so that you can add on when you decide to expand the pond or install a stream or waterfall. When it comes to depth, check with pond owners in your area to find out what works best in your climate. If the pond is too shallow, it will be difficult to care for fish or plants. The same is true if the pond is too deep.

2. Buying a pump that's too low in capacity or too high in electrical use.
Measuring proper pump size is another matter that should be given thought and consideration. A cheaper pump with lower capacity may seem like a bargain when you are in the store, but once you bring it home and it barely powers a little fountain, it will not look like such a good deal any more. Make sure to pay close attention to the energy use of the pump. Buying a cheaper brand that uses a lot of electricity will end up costing you more money in less than a year's time. You will spend more money on your electric bill than you would have if you had simply bought a better pump. Invest in a good pump with a decent warranty. Avoid ones that are oil-cooled, since they can leak oil into the pond.

3. Making the waterfall or stream too big or too small for the pond.
Adding a running water feature to a pond is a wonderful idea. Unfortunately, it is not always easy to figure out how big to make the stream or waterfall. You have to keep in mind the amount of water that will be used by the water feature, because this will drain down the pond when the waterfall is running, and fill up the pond when the waterfall is turned off. There are excellent books on the market for waterfalls and streams. Buy them, borrow them from a friend, the pond club, or the local public library, and study them before you put in a running water feature for your pond.

4. Ringing the pond in stone so that it looks like a necklace.
A pond is not particularly attractive when it looks like it has been edged by the kind of jewelry that Wilma Rubble wore in the Flinstones cartoons. At our nursery, the display ponds have what we call "planting pockets." These are areas that are scooped out along the perimeter of the pond, so that we can fill them with soil and plant water plants in them. Smaller sized stones are then placed over the soil. You can even build a bog garden at the edge of the pond, and then from there link the pond to your perennial border. Try to make your pond look like it fits with the rest of your landscape.

5. Neglecting to use enough plants to help balance the pond.
You may think that we recommend using plants just because we sell them. Ask any water gardener if more plants have improved the balance in their pond, and they will tell you that the plants have worked wonders. Oxygenators help reduce algae growth in the spring, and several marginal plants will help keep it to a minimum throughout the summer. Plants are also beneficial because they help shade the pond and keep the water temperature cooler through the heat of the summer.

6. Expecting the pond to look like a swimming pool.
North Americans are known for their cleanliness, and the same is true when it comes to their ponds. New pond keepers are aghast when algae starts to grow and the water clarity turns cloudy. This is normal, and a certain amount of algae is inevitable. You just have to know how to handle it and how to keep it to a minimum. You will never get rid of it completely, however. At least not if you want to have a pond with fish, plants and other living creatures. For those who cannot tolerate a single particle of algae along the side of the pond, or who cannot stand the usual seasonal changes of water clarity, we recommend that they get rid of their fish and plants, and that they regularly add bleach. If they want fish or water lilies, we suggest ones made of plastic. Having a live pond is like having children – you learn to appreciate their core beauty and overlook dirt or untidiness around the edges.

7. Having either too many fish or not enough filtration.
Many gardeners decide to have ponds in their backyards because they want to have fish. The rest don't realize that fish are needed until after they have installed the pond. Putting too many fish in the pond, however, can be a disaster. It can seriously compromise the quality of water and place the lives of all of the fish in jeopardy. Too many fish can quickly foul the water, deplete the oxygen level, and change the ammonia levels to serious or even toxic. This is especially true in the middle of summer when pond temperatures rise during the day and drop at night. We use a conservative recommendation of one six-inch fish for every 100 gallons of pond water. If you want to have a lot of fish in your pond, then read everything you can find on fish health, maintenance, and water quality, and be prepared to add hard goods to your pond, such as filter units and ultraviolet sterilizers, to keep your pond water healthy for the fish!

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