Backyard Ponds
A pond or water garden will likely become
the focal point for all your backyard conservation.
Backyard ponds and water gardens are for
birds, butterflies, frogs, fish, and you and your family. These ponds
are typically small, sometimes no larger than 3 to 4 feet in diameter.
They may be built in barrels or other patio containers. Water is
effective in drawing wildlife to your backyard. It is also a natural,
relaxing, and scenic addition that can provide interest and enjoyment.
Where to put a backyard pond
Consider locating your backyard pond where
you can see it from a deck or patio. Have it blend in with its natural
surroundings. Elevate the soil around the pond slightly so that excess
water will flow away from the pond, not into it. Make sure that any
drainage from the pond is away from your house. Plan to landscape
around the pond to provide habitat for frogs and birds that need land
and water. If you plan to use a pump to re-circulate water, use a
filter, or light the area, be sure electrical service is available.
There will be less maintenance if your pond is not under trees. Most
aquatic plants will grow better in full sun.
If you do not have space in your yard for a
built-in earthen pond, consider a "tub" pond or large water bowls.
These can be placed on the patio and provide many of the same benefits
as a built-in pond. There are numerous tub kits available that can be
as simple as adding water, a pump, and some plants. They can also be
moved inside in the winter as long as good lighting is provided for
plants.
Pond liners
Pond liners keep water from seeping into
the soil. Even in heavy clay soils, a liner is necessary. You can buy
rigid pond liners in a variety of shapes. These are durable and may
include built-in waterfalls. Many are quite small. If you want a larger
pool or would like to design your own shape, consider using a polyvinyl
chloride (PVC) liner. Use a liner specifically designed for pools.
While other plastics initially may be cheaper, many are not resistant
to ultraviolet light and will break down quickly. Some plastics may
also be toxic to fish. Liners also come in different thicknesses. A
thicker liner tends to be more resistant to punctures. While expensive
and requiring more expertise to install, cement is also an option as a
pool liner.
If you use PVC, you will need to get a
liner large enough for your pool. To determine how large a piece you
will need, determine the maximum width, length, and depth of your pond.
Multiply the maximum depth by 3. Then add this number to both the
length and width. This will allow enough plastic to be securely held
down around all pond edges.
Installing the pond
You can put in a backyard pond anytime the
ground is not frozen or overly wet. If using a pre-formed liner, dig a
hole to the correct depth and slightly wider. Insert the liner, making
sure it is level and sits securely in the ground. Backfill around the
sides. Add water, pump, and plants. Complete landscaping around the
pool. If you use a PVC liner, plan on at least a weekend to install and
landscape.
Steps to install a pond with a PVC liner:
Decide on your pond's location.
Using a hose or rope, lay out the shape of
your pond on the ground.
Once you are happy with the shape, start
digging. Stockpile your topsoil so you can use it to landscape around
your pond.
Plan for part of your pond being at least
18 to 24 inches deep; 24 to 36 inches is even better. This will allow
for a greater diversity of plants and fish to live in the pond. You may
want to make tiers around the inside of the pond at various depths on
which to place pots of different aquatic plants.
Make tiers about 12 inches wide to
accommodate the pots.
Remove any rocks from the excavated area.
To help prevent punctures in the plastic,
put a one-inch layer of damp sand on the bottom of the excavated area.
Spread the plastic liner over the hole. Let
it sag gently in the hole.
Place a few rocks or bricks around the edge
to hold in place.
Slowly start filling your pond. The weight
of the water will help smooth out the liner. Remove rocks holding the
edges to allow liner to conform to the edges of the hole. Smooth out
wrinkles but do not pull too tightly. You can walk on the liner if you
remove your shoes.
Finish off the pond by placing rocks around
the edge to securely hold the liner in place.
Install pump and filter, if desired. Many
smaller pumps have a built-in filter. For larger pools, a separate pump
and filter may be necessary. Make sure the filter and pump are adequate
for the volume of water in your pond. Pumps not only add interest, but
are important in adding oxygen to the water. If you want a fountain or
waterfall in your pond, you will need a pump to circulate the water.
Let the pond sit for a few days before
adding fish and plants. This allows chlorine to evaporate from the
water. Chemicals are also available that will quickly neutralize
chlorine and other harmful compounds.
Place plants at various depths and add fish.
Establishing plants
For ponds, consider a mix of emergent,
submergent, and floating species. Emergent plants, those that have
their roots in the water but their shoots above water, can be added to
the margins of pools. These include cattails (Typha spp.), arrowhead
(Sagittaria spp.), and water lilies (Nymphaea spp.). Submergent
species, or those that remain under water such as elodea, are often
used as oxygenators. These are plants that remove carbon dioxide from
the water and add oxygen. These plants are essential in most ponds to
keep the water clear. Floating species or those that are not anchored
at all in the pond include plants such as duckweed (Lemna minor), water
lettuce (Pistia stratiotes), and water hyacinth (Eichhornia crassipes).
While attractive, water hyacinth and water lettuce can be serious weed
problems in the south; however, since they are not winter hardy, there
is no problem with them spreading in northern climates. While not as
effective as oxygenators, these plants help keep the water clear by
limiting the amount of sunlight that algae receive. In tiny ponds
created in barrels and similar containers, these plants may be adequate
to maintain clear water.
Choosing and establishing plants for
ponds
Consider the following when selecting
plants.
How deep is the water? This will be a
factor in establishing plants and their survival over winter if you
live in colder regions. Some species need a minimum depth of 2 to 3
feet to grow well.
Is your pond permanently installed in the
ground or is it a small tub that will be moved inside in the winter? In
this case, even tropical plants may be an option.
Will you drain your pond in the winter? If
you intend to drain your pond, you should consider plants that can
spend the winter in a basement in a dormant state.
How much sunlight does your pond receive?
How large is your pond? If your pond is
small, consider dwarf species. Purchase plants from a reliable vendor.
Remember to include some oxygenator plants such as elodea.
Emergent and submergent plants should be
planted into pots. A wide assortment of pots is available, from plastic
baskets to pulp planters.
Choose pots that are large enough for
your plants.
If using baskets with numerous
perforations, line the basket with burlap or 2 layers of newspaper to
keep the soil from falling out of the holes.
Fill the container about half full with a
mixture of good garden topsoil. Do not use potting mixes or peat moss.
These are too light and will float out of the pot. Adding aquatic plant
fertilizer to this bottom layer of soil is recommended for some
species. Follow directions on the label for amount.
Place the plant on top of the soil and fill
the container with topsoil within one inch of the top.
When planting water lily rhizomes, make a
mound of soil in the middle of the pot. Place the rhizome at a 45
degree angle. The crown of the rhizome should be toward the center of
the pot. Cover the roots with soil, but not the crown.
In all cases, add a layer of gravel to the
top of the pot. This will help keep the soil from floating out and
prevent fish from digging in the soil.
Slowly place the pots in the pool to keep
soil from floating out. Place pots on bricks to get the desired height.
Floating species can be placed directly
into the pond with no other care needed.
Plants should cover 50 to 70 percent of the
water surface. Native plants usually do not need fertilizer. For some
exotic water lilies, limited fertilizing once yearly may be required.
Check with your nursery on care of plants and how deep to place potted
plants. Be aware that over fertilizing may cause unwanted algae blooms
which can rob the water of oxygen.
Add fish and scavengers
Consider stocking your backyard pond with
native fish. They are fun to watch and help keep the pond free of
unwanted insects. Most small ponds will warm up quickly in the summer,
so make sure you stock with fish that can tolerate elevated
temperatures.
You'll also need scavengers, such as
aquatic snails and tadpoles, to help control algae. In cold climates, a
heater may be necessary for fish to survive the winter. However, this
uses a significant amount of electricity and, in most cases, probably
is not justified. A better option may be to set up an indoor aquarium
in which to "over winter" fish and plants.
Maintenance
Algae is a common problem in many newly
established ponds. The water often becomes an unsightly green after a
few days. While your first instinct is to drain the pond and start
over, this only prolongs the problem. Once a pond is "balanced," algae
usually are kept at an acceptable level. A balanced pond is one in
which the nutrients are at the appropriate level for the plants
present. Excess nutrients and light are needed for algae. Reducing the
nutrients and decreasing the amount of light entering the water will
help reduce algae. Floating plants or those with broad leaves such as
water lilies will help reduce the amount of light available for algae
and compete for available nutrients. Scavengers such as snails will
help clean up wastes from the bottom of the pond.
Pond filters can help reduce algae, but
require maintenance. Filters need to be cleaned frequently if algae is
a problem. Chemicals can also be used to control algae. Use cautiously
as they can be toxic to other plants and aquatic life. The need for
algaecides should decrease as plants become established.
Excessive plant growth, especially of
free-floating plants, may be a problem. Periodically skim off excess
growth of duckweed, water lettuce, and other floating plants. Monthly,
prune dying plant material. Clean out some of the decaying plant
material that has accumulated in the bottom of the pond in the spring.
Remember: a natural pond is not a swimming pool and too much cleaning
can do more harm than good.
Safety
Locate the backyard pond where it is
unlikely to attract unattended children. Check local safety ordinances
to determine if a fence is required for the specific depth and size of
your pond.
Check local building ordinances for depth
and safety restrictions and permits. Equip outdoor outlets with a
ground-fault circuit interrupter. Unplug the pump before cleaning the
filter.
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