Creating An Aquatic Oasis

Before you go out and buy anything, you must first decide where you want to place your pond. Generally, you want to place it far from trees, as many pond plants, especially lilies, require a good amount of sunlight. Also, falling leaves can quickly accumulate in a pond, causing a cleaning nightmare. Avoid low areas, if possible, as you do not want a large volume of rainwater runoff to enter the pond. This runoff may contain pesticides, fertilizers and other materials harmful to fish. But DO place your pond where you can take full advantage of it. The most beautiful pond in the world will be for naught if it cannot be enjoyed. Try to tie it in to a patio or a sitting area in your garden. You will also want to check local laws to see if there are any regulations regarding the installation of ornamental ponds.
 

Once you have decided where to place your pond, it's time to choose the type of material you want to make your pond from, as there are several options:
1) concrete
2) bentonite clay
3) ABS plastic
4) rubber liner
 

The use of concrete and bentonite clay is beyond the scope of this article, and both should be installed by professional pond installers. However, a brief outline of both methods will give you an idea of what is involved.
 

Concrete can be used to make ponds of a variety of sizes, and is a good choice for larger ponds. However, this type of pond is best constructed by a professional. Improper construction can lead to more money being spent on repairs. Forms will need to be set in place, along with rebar, and you'll need to pour at least 4” to 6” of concrete to make a pond that will last. The concrete should be poured in one day, pouring the bottom first, then the sides. Planting pockets should be poured next, and then the top edge. Let the concrete cure for 5-6 days under a plastic tarp. After that, the concrete should be treated with muriatic acid to aid in preventing the high pH level usually found in untreated concrete ponds. After acid washing, let the concrete dry and then apply 2-3 coats of a paint made for garden ponds. Do not use paints made for swimming pools as they may contain an algae inhibitor which might be toxic to any plants you might add.
 

Bentonite is a type of clay that can be used to make large ponds. This material swells to as much as eighteen times its normal size when wet, filling in holes that might otherwise cause leaks, and creating a watertight seal. It needs to be laid to a depth of at least 4” to provide good waterproofing. This material, like concrete, is best applied by a professional in order to achieve the desired results.
 

Preformed ponds made of ABS plastic are a popular choice for most people. They come in a wide variety of shapes and sizes such as kidney, hourglass, and rock garden, and range in capacity from 25 to 300 gallons. Pre-formed spillways and waterfalls are also available. They are also easy to install, and most can be up and running in as little as a day.
 

Pond liners are another popular option, and can be found in most pet shops or garden centers, usually as a kit. They can be found in sizes from 10' x 15' to 20' x 25' or larger, and will allow you to build almost any size pond you want either by using them singly or by joining two or more together with a special adhesive. Most pond liners are made of rubber, and are very heavy, especially in the larger sizes. However, Tetra Products has a very strong yet lightweight Xavan liner that is easier to deal with. You can be creative with pond liners, as they give you the advantage of designing the shape of your pond, something you do not have with preformed types. But be aware, however, that a 19' x 26' liner will not make a pond of the same size. To choose the proper size liner, you will need to know the length (L) and width (W) of the pond at their widest points as well as the maximum depth (MD). We then use the formula L+(MD*2) by W+(MD*2). For example, let's say we want a 10 foot long by 5 foot wide by 2 foot deep pond. We would need a liner 14 ' x 9' so that we can make an edge above the water level. Your pond professional can help in determining what size liner you need.

 

Once you have decided upon the location and type of pond, it will be time to dig. Before you dig, however, just ensure that there are no underground gas, water pipes, sprinkler systems, etc, in the way. For concrete and bentonite ponds, the installers will be doing the excavation, saving you a lot of work. For overly large ponds you should consider having someone come in and dig the basic hole. This will save a lot of back-breaking work, and allow you to concentrate on leveling the hole out.
 

 For preformed ponds, installation is somewhat easy. You'll want to mark the pools perimeter on the ground, and then dig a hole slightly larger and several inches deeper than the dimensions of the pond. Take out any rocks, roots, etc, that might cause a puncture. For preformed ponds that have planting shelves, I like to dig the hole a lot bigger, and then backfill around the shelving. I find this a lot easier than trying to dig the shelves out beforehand. Once the hole is dug, tamp the bottom down so the soil is firm, and then pour 2” of clean sand on the bottom. This will provide a cushion for the bottom of the pond. Once the sand is in and has been tamped down, place the pond in the hole, and level it. You'll want the top of the pond at least 2” above the soil line so you can slope the soil away from the pond, thus keeping runoff from muddying up the water. Once leveled, you can start backfilling with loose, clean soil (no rocks or roots). I usually backfill with clean sand, tamping it down as I go, and topping off the last 6” with clean topsoil. When backfilling, make sure the pond remains level in the hole, and make adjustments as needed. Once backfilled completely, slowly fill the pond, making sure it does not settle incorrectly.
 

Installing a liner pond, while not as easy as a preformed pond, can be accomplished in a few days, depending on the size of the pond. Using a garden hose or two, outline the shape of your pond on the ground. Once you're happy with the shape, use spray paint to draw the outline on the ground. Start excavating your pond from the middle outwards, and don't forget to add planting shelves to the design. If this is going to be a larger liner pond, consider having a backhoe come in and do the majority of the digging for you. You'll want the pond to be anywhere from 18” to 36” deep, depending on how cold your winters get. If you are installing drains, you'll want to factor that in while you are excavating. Once you get to the edge of the pond, dig the walls at a slight angle as this will given them some additional support. As with the preformed pond, you'll want the edge of the liner pond slightly above the level of the surrounding ground, to prevent runoff from getting into the pond.
 

Once the digging is finished, and you're happy with the shape and depth, walk through the hole and remove and rocks, roots, etc, that you may find. Ensure that the bottom is tamped down and solid. Once this inspection is complete, add at least 2” of clean sand to the hole. This will provide a cushion on which the liner will sit. If the ground is particularly rocky, or if there are many roots, consider using a geotextile underlayer over the sand. This will give added protection to the liner.
 

Now you can install the liner. This is usually not a one person job, so get family and friends to help if need be. Open the liner to its full size, and inspect for any rips, tears or holes. Once inspected, walk the liner over the hole, and gently lay it in place, ensuring that it overlaps on all sides by the same amount (or thereabouts), and that there are as few folds as possible. Place bricks or rocks around the edge of the liner, to hold it in place, and start filling. There's no need to go inside the pond to adjust the liner. The water pressure will do that for you. If folds do develop during filling, gently tugging the liner should eliminate them.
 

Once the pond is filled, you can cut off the excess liner. Don't cut it too close to the water line, however. Leave 6”-8” of liner above the water line. This excess can either be buried or covered with stone.

 

Once your pond is in place, it's time to think about installing filtration. The type of filter used is going to depend upon the size of the pond. Some people forgo filtration altogether, allowing plants to do the bulk of the waste removal. While this works will in larger ponds, I would not advise it for the first-time pond owner. Small ponds can use internal canister type filters hooked up to a submersible pump. There are also pressurized external canister filters available. They too are hooked up to a submersible pump. Their main advantage is that they are easier to get to when cleaning is needed, unlike the submersible filters. Larger ponds, naturally, will require larger filters. Swimming pool sand filters are a good choice for larger ponds as they can handle a large volume of water, and are easily cleaned via backwashing. Whichever filter you choose, make sure that it is serviced on a regular basis so the water remains clear. To that end, many pond owners hook up a UV (ultraviolet sterilizer) unit as part of the filtration package. These units aid in combating “green water”, which is a floating unicellular algae. The outflow from your filter system can be delivered directly back into the pond, or diverted into any number of water features such as waterfalls and fountains. Such features add much to the overall look of the pond as well as providing for aeration. Using a filter will also help ensure your pond does not become a breeding ground for mosquitoes. These pests lay their eggs in still water, so anything that agitates the water will prevent this. You can also add larvicides, such as Mosquito Dunks, to the pond to kill any mosquito larvae that might show up.

Of course, adding fish to the pond will also aid in eliminating the mosquito problem as the fish will usually eat the larvae. This should be done 3-4 days after the pond has been filled and the filtration running. Goldfish and koi are the usual choices, although koi may uproot and eat plants. When stocking your pond, don't overcrowd. Remember, the fish you are buying are young, and will grow. With goldfish, one fish per 50 gallons is a good stocking rate. With koi, however, you are better off stocking them at 500 gallons for the first fist, and 100 gallons for each additional fish. It's better to lightly stock your pond than to overcrowd the fish. They will be much healthier that way. Both goldfish and koi can overwinter in the pond providing it is at least 24” deep. You can also use native species, such as sunfish, catfish, and the like, providing your local laws allow for this. You will also most likely get visitors to your pond: frogs, dragonflies, turtles, and even snakes may find the water attractive. This is all part of pond ownership, and such visitors should be encouraged. Speaking of visitors, you may also notice fish-eating birds visiting your pond once in a while. In some areas, this is unavoidable. You may need to place wires above the pond at a height of about 8-10 feet, to discourage the birds from landing and possibly eating your fish. If the pond is deep enough, the fish may be able to evade these predators, but in shallow ponds, these birds can be problematic.
 

During the late spring until the water temperature falls below 50 degrees, you'll need to feed your fish. There are many brands of floating koi/goldfish foods on the market, all of which will suit the needs of your fish. You'll want to feed sparingly as the biggest problem with pond fish is obesity. Feed no more than they can eat in a couple of minutes 2-3 times per day.

Once the pond is up and running, you may want to consider adding plants. Lilies, of course, are the first plants that come to mind. Lilies come in a variety of sizes and colors and you can find one to fit almost any size pond, from the relatively small Blue Daubin to the humongous Victoria Lily. They also come in a variety of colors, from pure white, to dark red, along with those whose blooms change color. Then there are marginal, or bog, plants. These plants sit in the shallow part of the pond, or on planting shelves, and include Iris, horsetail, pickerel weed, Papyrus, arrowhead, cattail and bullrush, to name but a few. Your local garden shop or nursery should be able to help you pick out plants suitable for your locale. Whenever possible, choose winter hardy species as they will bloom year after year, and save you the problem of having to replant each year.
 

This article has really only scratched the surface of setting up an ornamental garden pond. There are many online resources and books that go into greater depth, and I urge anyone considering a pond to do further research. In the end, a garden pond can be very rewarding and enjoyable. I know I enjoy mine, and have even incorporated it into my garden railroad. With a bit of planning and imagination, you too can enter the wonderful word of garden ponds. Happy digging!