16 Garden Pond Building Tips

Make the Pond Edges Level

Dig the garden pond so that all edges around the perimeter are the same height, with no deviation.

A garden pond's water level is only as high as the lowest point of the perimeter. Any low points are spillover points. Retroactively building up low edges is difficult, so plan this in advance.

Choose Pond Depth Wisely

Deep or shallow, the depth of the garden pond affects many aspects once the water is in place: algae, safety, fish, appearance, and more.

• Deep: Deep ponds have a less visible bottom and no visible rock. Fish might tuck themselves away, hidden. Deeper ponds also require more pond liner. Deep ponds can be a safety hazard if there are children—even children in the neighborhood.
• Shallow: Shallow ponds are better for displaying decorative rocks on the bottom, and fish are more prominent. However, shallow ponds build up algae faster because the light can reach more water with greater intensity.

Protect the Liner Against Burrowing Animals

Burrowing pests such as groundhogs and moles can dig up holes in a lawn and garden. But the problem goes well past the point of annoying when the burrowing animal exits upward—under your garden pond, chewing away the pond liner.

The solution is to lay down a metal mesh called hardware cloth as a base for your pond bottom before shoveling a few inches of dirt over it. Then, the underlayment and liner go on top of the dirt layer. If your sides are dirt, not retaining wall block, then you should lay hardware cloth on the sides, too.

Budget for the Pond Liner

Given the overwhelming expense of EPDM pond liners, the liner sometimes dictates the size of the pond. A quality 45mil EPDM liner, 15 feet by 20 feet, costs between $325 and $375.

If money is tight, you can save money with a PVC liner, but PVC liners don't hold up to the elements as well as EPDM liners. Plus, PVC liners are stiffer than EPDM, so they don't conform to the pond's shape as well as EPDM.

Accentuate Shapes

If you want the pond's curves to show up, give them a bit more curve in the digging stage. Delicate nuances like curves and inlets look great in the digging stage. But they tend to get smoothed out and even obliterated with each stage of the pond-building process.

Adding underlayment, liner, rocks at the bottom of the pond, and especially rocks along the pond's bank all contribute to this softening process.

Create a Diversion Point For Spillover

Create a predictable spillover point so water can go to a safe spot if the pond overflows. You don't want the pond to spill into basements or around the foundation.

Spillover occurs in wet areas. It can even happen in dry areas if you overfill the pond.

Avoid Tall, Vertical Pond Walls

Avoid building tall, vertical pond walls since loose, natural stones are difficult to stack vertically. Not only does the rock tend to fall, but a greater number of or larger rocks are also needed to cover this area. If possible, try to keep the garden pond banks at a 45-degree angle or less.

Install a Water Filter and Skimmer

Installing a permanent water filter is the gold standard for garden ponds. A filter mounted on the side of the pond stays out of the way. Since it is automatic, it will turn on at set intervals.

While a permanent filter is more complex and costly to install at first, it makes for easier pond maintenance over the long term. Your other options for filtration will be manual skimming or floating filtration devices.

Hand skimming is a constant job. Floating filters take up a lot of water on the surface and are unsightly.

Terrace the Pond Bottom

Sloped garden pond banks, if angled sharply enough, cause rocks to slide to the bottom. To avoid this, terrace the garden pond's sides and bottom, much like farming terraces or stair risers and treads.

Keep each terrace riser at most about 6 inches high to avoid stacking rocks too high. Create terraces by cutting them directly in the dirt with the shovel, as long as the dirt is packed tight enough to hold shape.

Cover the Pond Liner

Cover the pond liner with rocks, pebbles, smooth gravel, or plants to prevent deterioration. A professionally built garden pond does not show a pond liner, inside or outside.

Near the edges, at ground level, pare back the pond liner to about a foot from the edge of the pond. Doing so means less liner to cover up.

Find Natural Sources For the Rocks

Look for rocks for your pond whenever you are out. When you go on a trip and find a legitimate source of rock, toss a few in your car. Rivers are a good source of rounded river stones. Beaches, too, provide an endless source of pebbles, round stones, and sand. Just make sure that you can legally take the rocks.

Think Ahead to Cleaning

Owning a garden pond means keeping it clean. A garden pond collects everything that falls on it, including leaves, dust, dirt, and debris.

Rock the pond bottom so that it is smoother and easier to clean. Heavily rocked pond bottoms and jagged rocks are difficult to clean, while smaller, smoother rocks are easier to clean.

Use an EPDM Liner For Durability

Even though PVC pond liners are vastly cheaper than EPDM liners, EPDM liners are usually worth purchasing if you can afford them. EPDM liners are thicker and far more durable than PVC liners.

EPDM liners resist UV rays well; even chemicals such as chlorine are no match for EPDM. Also, when warmed by the sun, EPDM liners become pliable and fit well into the pond hole.

Protect the Pond Liner With an Underlayment

Protect that expensive EDPM pond liner by resting it on an underlayment. A pond underlayment softens rocks and roots in the soil. The water weight of a fully loaded pond can eventually cause sharp objects to pierce the liner.  

Install an underlayment made of polypropylene nonwoven needle-punched fabric. You can also add a 1-inch layer of sand or old carpeting.

Terrace the Pond With Foam

Use landscaping or rigid foam blocks to terraform the earth below and around the garden pond.

Cans of landscaping foam, similar to insulation foam, are perfect for adding extra touches to curves. Large sheets of insulation foam can be creatively cut and stacked to provide a garden pond's basic terraced shape.

Protect Against Algae Growth

Move or angle the garden pond away from sunlight to mitigate the problem of pond algae. Sunlight promotes algae growth in garden ponds.

If you want sunlight on your garden pond, you'll want to look into natural algaecides or inhibitors. Some pond owners drain their ponds during the most light-prone times of the year to avoid algae altogether.