A Greener View

If properly designed and maintained, backyard ponds and water gardens can offer tranquil refuges that lower stress and enhance the beauty of your landscaping and the value of your property. At the same time, an improperly designed and maintained water feature will create so much work that it will often be filled in.

A properly designed and maintained pond has clear water, it looks and sounds good and fits in its surroundings, it is safe and has stable edges and walls, it has a healthy environment for the fish and other creatures all year long, it is affordable to build and maintain with the maintenance being around fifteen minutes per week. Unlike what many authors will tell you, a backyard water garden pond doesn’t have to be a specific shape or have a minimum size and depth or have specific filters, and it may or may not have fish, plants and other creatures. All of these specific details depend on the pond style.

POND CONSTRUCTION QUESTIONS

1.                  What kind of pond should I build? ‘Pond Styles’ The answer to this question will help answer all of the other questions. A re-circulating water feature fills the pond with rocks or covers the pond, so just the moving water is visible, while the pond remains hidden. The smallest pond with visible water is called a starter pond and it is usually made from a hard plastic shell. It is best suited for above ground applications, but with special care can be installed in the ground. The next size up is the basic water garden that is mostly for plants and a few small fish. Larger, more extreme water gardens can be built deeper and can house larger fish. The much deeper and often bigger Koi pond, is designed to effectively care for large fish.

2.                  How big should my pond be? ‘Pond Size’ No matter which style you are looking at, make it as large as possible, as larger ponds are less costly per gallon and require less maintenance. They are more stable ecologically, safer for fish and hold more lilies and other plants. A common complaint from first time pond owners is that they wish they had a bigger pond. There is already plenty of dry land in your landscape, so make your pond as big as you can.

3.                  How deep does the pond have to be? ‘Pond Depth’ Typical depths vary from about 18 inches in starter ponds, range from two to four feet for water gardens and to six or more feet deep for Koi ponds. Each of these ponds can be made deeper since more water volume is better for the fish. Check local codes for depth allowances and any fencing requirements. Ponds for plants only or including just a few small fish are better shallower, as they are safer, easier to clean and plants need sunlight which deeper water areas don’t get.

4.                  Where should the pond be installed in my yard? ‘Best Location’ The best place is where it will be the most visible. Generally, this is in the back yard near the house and deck or patio. Visibility from inside will make the pond much more enjoyable. If it is way out in the back, it will be hard to see, unless a viewing area is also built. It should never be built in a low area of the property. Rains can wash in too many chemicals, leaves and debris. Also, the fish can swim away if the landscape floods.

Trees can be a problem if they provide too much shade. There are many water garden plants that thrive in the shade, but they may not be the ones you want to grow. Some shade is beneficial to the fish and to slow the growth of algae. Leaves can be a problem in autumn if you do not have a mechanical filter called a skimmer. Covering the pond with a net may be necessary to keep out the majority of leaves.

Always make sure the area of the pond has no utilities buried underground before you start digging.

5.                  How much will it cost? ‘Pond Cost’ Just like any landscape project there are a range of costs. You can put the pond in yourself or have someone else do it for you. The landscape around the pond may need additional work done after the pond is in. The pond and landscaping can be phased in to some extent. Most pond kits don’t include everything that is necessary for the pond to be complete, like fish and plants. Plants and fish can be bought small and grown on to larger more expensive sizes if you have the time to wait. The pump can be bought as an energy efficient model that will save long term costs, but is often higher priced to purchase.

Small container gardens kits start at about $100 while full-size water garden kits with filters and waterfalls run from around $1,000 to five or ten times that. Koi ponds start at around $4,000 and if they are made from concrete can cost much more. A well maintained water garden pond installation can return dividends, not only in year-round enjoyment, but also in increased property value. When a professional installation is desired, qualify the prospective installer and then visit some of his demonstration pond sites before signing.

6.                  Should I use a flexible liner or a preformed pond? ‘Liner Material’ Any container that holds water can be used for a water garden, but some are easier to use than others. Hard-shelled ‘pots’ are best used above ground. Flexible liners easily fit the size and shape of your landscape and of the hole you actually dig. It is easier to dig a hole deep enough to over winter the fish outdoors when you use a flexible liner.

            Concrete is difficult to use in a natural pond. It is expensive and labor intensive to install. It can easily crack with frost action and can actually float out of the ground if it is in a high water table area. Lights installed permanently in the concrete require the pond to be partially drained to replace a bulb and are immovable. Lights hidden in the rocks on a liner can be rearranged whenever you want.

For a preformed pond, you must dig a hole the exact shape of the plastic pond. If the hole is too big or deep in some spots, the plastic may deform and crack because of the weight of the water pushing down. If the soil has a lot of clay, the pond may float out of the ground during rain storms. It can also lift out of the ground due to frost action in the winter.

Preformed ponds are more difficult to filter or skim. The filter and pump in the pond are ugly to look at and a safety hazard. If the fountain leans over, the pump can shoot the water out, draining the pond and you might lose all the fish and plants. These ponds are usually too shallow to over winter fish in cold climates and they can overheat in warm climate areas.

7.                  Do I need a pump? ‘Pump’ Pumps move water to create fountains, waterfalls and move water through filters. They are highly recommended to keep your pond clean and create moving water. Splashing water looks and sounds beautiful and attracts birds like no other garden feature. For the same number of gallons pumped per hour, some pumps use less electricity. Submersible pumps tend to use more electricity than in-line pumps.

8.                  How big of a pump do I need? A properly filtered water garden pond has all of the water in the pond going through the filter system once an hour so the pump size would match the size of the pond. Another factor to consider is how much water you want to flow over a waterfall or through a stream. You will get a two inch wide by quarter inch thick waterfall for every one hundred gallons per hour of water flow. Remember, you lose some volume the farther and higher it must be pumped, so larger pumps are needed.

9.                  What do I do with the pump in the winter? Usually, the pump is not used in the winter. When the water drops down into the 40s we turn it off and plug in a de-icer. When the pump is removed, the biological filter can be drained. Any filter materials can be cleaned up and stored for the winter.

10.              Can I use rocks and gravel? ’Rocks’ Just like in an aquarium, rocks provide more surface area for beneficial bacteria that are part of the balance in any starter pond or water garden. A thin gravel layer of about one-inch thick will help avoid anaerobic (low oxygen) conditions on all shelves below one foot deep. In shallow water, gravel can be thicker for plant roots to grow in. Gravel and rocks are usually avoided in deep Koi ponds.

            The 45 mil EPDM liner material is very durable and can easily handle large boulders and being walked on at the same time. The pond looks nicer with rocks. Instead of seeing ugly folds and wrinkles you see more attractive rocks. With the plants growing in the rocks instead of pots, the whole pond will look much nicer.

            The old fashioned look of flagstones around the pond edge separates the dry land and wetland plants, so it does not look natural at all. The flagstones do not work well at keeping the liner from falling in and can be dangerous for someone who steps on one that overhangs the water too far.

11.              What do I do with all of the dirt I dig out of the hole? Dirt is heavy, so you will not want to take it very far. Since most people want to make a waterfall or stream, it is often easy to make a sloping hill next to the pond. This hill also makes a nice background that can be planted with many perennials.

12.              Do I have to add fish? ‘Fish’ No, but fish do eat mosquitoes and are recommended. They are very easy to care for, help eat pond algae and can be trained to eat out of your hand. They add color and personality to any pond. Be careful not to buy too many or let them out grow the size of your pond or the filter system. Fish, plants, bacteria and the water’s temperature and chemistry all need to be at proper levels for everything to have a natural balance in the pond. This is not hard to do, but it is easier if all of the parts are in place.

13.              How many fish can I put in my pond? It is hard to know exactly how many fish will fit in to a pond. It will depend on what kind they are, how big they are, how much water there is and how well the water quality is maintained. At first, there should only be a few fish in the pond to make sure the new filter system is working properly. Ultimately, the fewer fish there are in a pond the healthier they will be.

A one foot long fish has more mass than thirty, three inch fish and therefore more biological load on the filter system. There should be about 500 gallons of water for a one foot long fish or 500 gallons will support more than twenty fish three or four inches long. Too many fish in a pond will over load the filters and there will be more fish health problems. Remember that fish grow, but filters don’t.

14.              How much do the Koi cost? There is a wide range of costs with these fish. There are fish shows that people take there fish to and have them judged, just like people do with dogs or horses. Prize winning animals of any kind sell for large sums of money. Koi and goldfish come in several grades. Pond grade is the entry level, it is kind of like buying a mutt from the pound. A three inch fish may cost only a few dollars. Grade A and B fish cost more and ‘show grade’ fish cost the most. The price is based on size, color quality and color pattern. The larger it is when it comes from the breeder, the closer it will resemble his breeding stock and the higher the price will be. Fish that do not look like the breeding stock are culled out at a small size and sold inexpensively. It will cost you the same amount of money to maintain an entry level fish as it does a grade A fish. The grade A fish will have better color and it will maintain it’s colors for a much longer time.

15.              Our neighbors have cats, will they eat the fish? ‘Predators’ Depending on where you live you can have different kinds of predators come to your yard. Cats rarely attempt to catch fish in the pond. Areas with predators that can swim, like alligators, otters and some kinds of birds need to use barriers to keep the animals from getting into the pond. Animals like raccoons and herons that have to stand on the shelves of the pond are thwarted by designing the pond properly.

            Steep side walls that rise above the water several inches give the fish some room to swim away from raccoons that cannot swim to catch the fish. Hiding places and deep water give the fish the edge over herons. There are several products on the market that spray water at or give a shock to predators that come near a pond.

16.              I want to make a waterfall out of mortared flagstones, how do I keep the water from leaking out the back? ‘Waterfalls’ It is very difficult to make a water fall that way. You can lay down a liner first, to force any leaking water back into the pond. Mortar is difficult to use because it is inflexible. It will leak when it cracks due to frost action, but it will be difficult to remove from the rocks when you need to rebuild. Instead, use polyurethane foam sold in cans at the hardware store for filling leaks in the insulation of a wall. It is flexible enough to fill any cracks in the rocks and is less bothered by the weather. It is easy to pry it off of a rock if you need to redo any part of the waterfall.

            Using a pre-built waterfall box makes it easy to build a waterfall. The water fills up the box and looks like a natural spring. The water then flows in a controlled manner over the spill way, where you can foam into place a nice flagstone. The liner runs up the front surface of the box like a bib, so that the water stays in the pond. Rocks hide the liner and it looks great. The inside of the waterfall box may double as a biological filter, depending on the size and what the manufacturer supplies. Water plants can be planted in baskets or floated in the top to make it look even better. The plants also help in the filtration of the water.

17.              How hard is it to put in a stream? ‘Streams’ Streams are easy to install. Water in nature erodes away soil, so for the stream to look natural it must be carved into the soil. Fake plastic streams set on the ground never look right. Flexible liner fits into the area dug out for the stream and once the rocks are in it will look like it has always been there. Streams have two shapes at the same time: a bathtub and a staircase. The side walls of a stream hold in the water, just like in a bathtub shape. Carving the ground out for the stream with a tread-riser, tread-riser staircase pattern makes it easy to have several waterfalls along the stream's length. Stepping stones and bridges can be used to cross the stream.

            Liner can be taped together if necessary, to provide a water tight seal between two pieces of stream liner or the stream and the pond. If the stream falls into the pond with a drop, it may not be necessary to tape the two pieces together.

POND MAINTENANCE QUESTIONS

1.                  How much work is it to maintain a pond? ‘Maintenance’ That depends on your pond size and type. In general, though, larger ponds are less work, as they are more stable chemically and thermally and larger filters take longer to get dirty. Contrary to what one might think, the starter pond is the most difficult to keep clean because you have to do all the work. With a pump on the bottom of a starter pond all the debris gets pulled to the pump and you have to get it out of the pond, sometimes daily or even several times a day. Water gardens that are filtered with a skimmer and a biological filter stay cleaner, with the filters doing some of the pond maintenance instead of the pond owner.

2.                  Do I need a filter? ‘Filters’ Yes, for lower maintenance and better fish health. Clear ponds can be built without a filter, but the right filters make pond maintenance easy. Ponds need cleaning just like kitchens, living rooms, garages and patios. Maintenance chores, like cleaning, can be put off, but in ponds the longer you wait, the dirtier they get. The benefit of filters is that they help clean the pond for you.

Starter ponds have filters in the pond, making them harder to maintain. They are often too small to filter very well and bigger filters would be even harder to hide.

Water gardens often use a dual filter system. A mechanical filter (skimmer) removes dust and debris while also protecting the pump from clogging. The clean water is pumped to a biological filter to remove invisible chemicals that are toxic to the fish.

Koi ponds often use multiple skimmers and bottom drains to remove the water from the pond. The water may go to a variety of settling tanks, pressurized filters, ultraviolet lights, ozone generators, and biological filters before going back to the pond.

3.                  How big does the filter have to be? In general, the bigger the better, as bigger filters last longer between cleanings and handle larger amounts of fish waste products. Filters installed outside the pond are easier to service when they do need cleaning.

There are two kinds of filtration that need to be done. Mechanical filtration is the removal of large debris, from dust to leaves. In the old fashioned way of doing a pond, the pump was at the bottom. Since the leaves go to where the suction is, they ended up at the bottom of the pond and now the pond owner became the mechanical filter. Since most of the leaves fall in autumn when the water is cold, it was not a fun job trying to remove them. If you tried to take the pump out standing on the shore and pulling on the cord or tubing it sometimes came apart. This could electrocute the fish. If you waded into the pond to get the clogged pump and filter you found out that it was heavy, wet and very dirty, not a fun combination. In some ponds, algae or leaves clogged the pump and filter within an hour, all day and night long.

            A skimmer removes large debris out of the pond 24 hours a day all season long. The pump is in the skimmer, so that is where the suction is and leaves end up outside the pond in a net bag. Having the pump in the skimmer box is also safer. The traditional method of a pump near the bottom of the pond is a disaster waiting to happen. If there is any pipe or fountain or waterfall that could get water out of the pond, Murphy’s Law says that someday it will. With the pump near the bottom, it will send all of the water out of the pond and you will lose all of the fish and plants. This has happened many times in the past. If the same thing were to happen with the pump in the skimmer box, the water would go from the top of the door to the bottom of the door and then stop going in the skimmer. You would only lose a few inches of water off the top of the pond. With a low water shut off switch in the box, the pump turns off automatically and does not run dry and burn out.

            The second kind of filtration we need in a pond is biological. Fish release ammonia through their gills every time they breathe. Ammonia is toxic, so it must be removed. Certain bacteria break down the ammonia for food. Their waste product is nitrite and it is also toxic to the fish. Other bacteria break down the nitrite, turning it into nitrate which is not very toxic. Plants (including algae) use the nitrate for food.

            We need lots of bacteria to keep the fish healthy and we need to get the water that has the waste products in it to where the bacteria are. Bacteria grow on rocks, filter pads and other surfaces in the pond and filter system. Some materials have more surfaces and allow for better water flow. An inch layer of filter pads is equivalent to 10 inches of gravel. It is much easier to clean out a filter pad than it is the gravel.

            A good filter system will take all of the water in the pond through the system once an hour. If the pond is small or has lots of fish, more filtrations per hour are recommended. Large ponds, over several thousand gallons, can have one filtration every two hours. If we could take the pads out of the filter, we would like to have the equivalent coverage of about one third of the pond's surface one inch thick in pads. The larger the pond, or the more fish in the pond, the larger the filter system needs to be.

4.                  How often will I have to clean the filter? Biological and mechanical filters should be cleaned whenever they slow the flow of water. There may be periods of time in the spring and fall when the skimmer cleans debris out of the pond so fast it needs cleaning daily, while in the summer it may be weekly or every ten days.

5.                  How do I get rid of green water? ‘Algae’ If you find your pond growing excess algae, that usually means it is “under filtered”, and nature is responding, by adding algae to complete the filtration process. Create a living ecosystem in your pond. Plants, sufficient filtration, pumps, beneficial bacteria and decorative gravel added to your pond should eliminate most green water problems. The fewer fish and the less they are fed, the fewer nutrients there will be available for algae. Don’t change your pond water unless also changing to a better filtration system or ecosystem. Don’t simply add an ultraviolet light to kill the algae, without first setting up filters and an ecosystem.

6.                  How do I get rid of long string algae? String algae is a plant that consumes a lot of nutrients, helping to keep the pond water clear of green water algae and fish feed on it. It is an important part of many pond ecosystems. Good pond filters and pond care is usually all that’s needed to reduce it to a tolerable level. If it becomes excessive, it can be removed by hand. There are also mild pond additives that suppress the growth of string algae. We are looking to control algae, not eliminate it. Be patient. A pond ecosystem may take as long as two years before string algae is controlled naturally.

7.                  How do I over winter my fish and plants? ‘Winter’ Even in freezing climates like the Northern U.S. and Canada, fish and plants are best left outdoors to hibernate naturally. A two-foot deep pond with a surface aerator or heater to keep a hole open is sufficient for most ponds up to zone 5. Clean the pond of debris before the pond ices over. In colder climates and with larger fish, a larger deep area is better as the warmest water (around 40° F) is denser than colder or warmer water, so it forms a “warm puddle” on the pond bottom.

8.                  Doesn’t the water freeze all the way to the bottom? Water at around forty degrees is denser than water warmer or colder so the forty degree water sinks to the bottom and forms a puddle that doesn’t mix with the other colder water. The colder water eventually forms ice over the top of the pond. The ice insulates the forty degree water from the colder air above the pond.

There are only so many gallons of water in any pond. There is only so much oxygen in that water. When the ice caps over the pond, the fish might eventually consume all of the oxygen, so we keep a small area open for gas exchange with the atmosphere.

            We can use small air pumps, water pumps and electric de-icers set for about 38° to keep an area open. We can put a large board or sheet of plastic over these tools to insulate them and keep a larger area open. We still want the ice to cover a large pond area for insulation.

            We turn off the filtration water pumps in the fall when the water temperature drops to forty for two reasons. The bacteria that do the biological filtration are not very active at this low of a temperature and we want the forty degree water to form a puddle at the bottom. If the pump keeps running, especially on a small pond, it will mix the water until all of it is in the low thirties. This will harm the fish and dormant plants that are at the bottom of the pond.

            After the ice forms it wants to get thicker. If there is a forty degree puddle it must give up some heat to let the ice form. This slows the ice from reaching very deep. If the water was mixed and there is no forty degree puddle to give up its heat, the ice will form quickly and can reach all the way to the bottom.

            In northern Illinois, we would like at least one third of the volume of water in the pond to be around two feet deep, so we can have as large of a forty degree puddle as possible. The deeper you go the better, but the deeper you go without changing how wide the pond is, the steeper the sides will have to be. A pond 10 by 15 that is a maximum of 2.5 to 3 feet deep is a nice size. This size will allow for a few Koi and goldfish. Deeper water will allow for more fish. More water means more stability chemically and thermally. There is very little additional cost in making the pond deeper.

9.                  How hard is it to grow plants in the pond? ‘Plants’ The nice thing about water garden plants is that they are easy to grow. You can’t over water them and you will have a hard time under watering them. Plants in the water garden can be annuals, tender perennials, tropicals or perennials. Annuals die at the end of the year and many people treat perennials originating in tropical climates as summer pond annuals. Hardy northern perennials are very tolerant of being frozen. Tender perennials over winter in deeper water where the water doesn’t completely freeze. Water lilies and lotus are both hardy plants in Illinois, as long as they are down in the bottom of the pond where the water and roots don’t freeze. A tropical plant can be brought indoors to survive the winter.

            Some people leave the pond plants in pots, but many grow better and make the pond look more natural if you take them out of the pot and plant them into the gravel that covers the liner. On a shelf, make a campfire ring of larger stones. Fill the inner area with gravel. Add a plant and you now have a rock flower pot where the plant roots take their nutrients out of the pond.

Plants that are growing in the rocks and not in pots will compete successfully with algae for available nutrients. By taking nutrients out of the pond water, the plants feed themselves and help prevent algae blooms. It is okay to leave some plants in pots, such as those that will be taken indoors for the winter, but they do not compete with the algae for food.

The same design principles apply to wetland water garden perennial beds as they do in dry land perennial beds. Use tall plants as backdrops, use a variety of leaf colors, textures and shapes. Use a variety of blooming times and colors. Many plants that are labeled for growing in moist garden soil will do well in shallow gravel planting areas along the shoreline of a pond. These plants can be used on both sides of the pond liner to help blend the view from the dry land to the wetland.

Do a planting plan for the wet land flower bed ahead of time and design the planting shelves for the types of plants that will be planted on them.

10.              What chemicals do I need? ‘Chemicals’ You can either sterilize or fertilize your water feature. If it is small and not designed for a living ecosystem, then you can sterilize it, but a backyard water garden pond is designed to be growing and living, so we try to work within the system. Very few pond chemicals are needed with a water garden pond. City water must be dechlorinated before it is safe for fish, but beyond that, a natural ecosystem requires very few additional chemical products. Pond bacteria are an essential part of the pond’s ecosystem. Regular additions of pond bacteria products can be added to help keep your pond cleaner. String algae is the chief exception to occasional chemical use. There are pond safe algaecides for use against algae.