15 Garden Pond Building Tips

Level the Garden Pond Perimeter to Close Tolerances

When digging the hole for the garden pond, remember that a garden pond’s water level is only as high as the lowest point of the pond perimeter. In other words, the entire perimeter of the garden pond needs to be as near to the same height as possible.

This might be a point that seems obvious from afar, but when you are digging the pond it can often escape attention. Since an exact level is not possible, think in terms of deviation and tolerances.

For example, if your chosen pond depth is 24 inches, the perimeter’s deviation from that height should be as little as possible: just an inch or two.

Decide Whether the Pond Will Be Shallow or Deep

The depth of the garden pond is an important decision that affects both the cost and the eventual appearance of the pond.

As the pond gets deeper, the bottom becomes less visible and rock cannot be seen. Fish might tuck themselves away, hidden. Deeper ponds also require the use of additional expensive pond liners.

Shallow ponds are better for displaying decorative rocks on the bottom and fish are more prominent. But shallow ponds tend to build up algae faster because the light can reach more of the water with greater intensity.

Protect the Pond Bottom Against Burrowing Animals

Burrowing pests such as groundhogs and moles can dig up holes in a lawn and garden. When you have a burrowing animal in your yard, it seems like you’re always filling in holes.

But the problem goes well past the point of annoying when the burrowing animal exits under your garden pond, chewing away the pond liner in the process.

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 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.

Reconcile Eventual Pond Size With Pond Liner Size

A garden pond can only be as large as the size of its underlying pond liner. So, long before any shovel meets the dirt, you’ll need to figure out how big the pond should be, in conjunction with the size and price of the pond liner.

Quality pond liners made of ethylene propylene diene terpolymer (EPDM) are very expensive. PVC liners are expensive but less so than EPDM.

In a project that involves the use of free or low-cost materials such as rock, concrete slabs, retaining wall blocks, and the lowest cost item of all, water, spending hundreds of dollars for a sheet of the liner can seem like a major purchase.

If your budget is tight, then the cost of the pond liner will always dictate the size of the pond. On the other hand, you might find that it is worthwhile to put a little extra money into a high-visibility, curb appeal project such as this.

Early Shape Nuances Are Often Lost

When you initially create the shape of the pond, you may find yourself adding special curves and inlets that you feel will give the garden pond a unique look.

But these early delicate nuances often get softened and obliterated with each subsequent stage of the pond-building process. Adding underlayment, liner, rocks at the bottom of the pond, and especially rocks along the bank of the pond all contribute to this softening process. Think in terms of basic shapes.

Add a Top Spillover Drain in the Design

Unless you live in a parched, arid climate, your pond will inevitably overflow. Yet even in dry areas, this can happen when you are filling with the hose and let the time slip away. Rather than having the pond spill over and race toward your house foundation, create a predictable spillover point so that water can go to a safe spot.

Avoid Tall, Vertical Garden Pond Walls

The more vertical and tall the walls of the garden pond, the harder the job you will have when you apply stone to the pond. Loose, natural stones are difficult to stack vertically. Not only does the rock tend to fall, but a greater amount of rocks or larger rocks are also needed to cover this area.

Small rocks are less expensive but hard to stack. Large rocks cover vertical spaces easier but are costly and difficult to move. Try to keep the garden pond banks at a 45-degree angle or less, if possible.

Install a Permanent External Water Filter and Skimmer

Unless you make provisions for a permanent water filter mounted in your pond’s wall, your only options for filtration will be manual skimming or floating filtration devices.

Hand skimming is a constant job while floating filters take up a lot of water surface and are unsightly. A permanent water 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 difficult and costly to install at first, it makes for easier pond maintenance over the long term.

Terrace the Pond Bottom

Sloped garden pond banks, if angled sharply enough, result in sliding rock at the bottom and sides of the pond. Instead, terrace the garden pond’s sides and bottom, much like farming terraces or stair risers and treads.

Keep each terrace riser no more than 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.

Plan to Cover the Pond Liner

Every single square inch of pond liner must be covered up. Even the best, most expensive pond liner is subject to the sun’s punishing UV rays and will break down.

The way to protect against deterioration is by covering up all of the liner with something permanent, like rocks up the sides, river pebbles, or smooth gravel on the bottom. It’s better to think ahead about how you want to cover up the liner. Doing so in hindsight often means overloading the pond liner.

For example, if you keep the pond terraces low enough, you can use smaller rocks. High terraces demand larger, more visually intrusive fill items.

Be Inventive About Sourcing Your Rocks

Garden ponds require a lot of rocks on the bottom and the sides to cover up the liner. If you were to purchase all of the rocks, the cost of the pond would increase substantially.

Instead, look around for rocks that you can use 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 for rounded river stones.

Beaches, too, provide an endless source of pebbles, round stones, and sand. Just make sure that you can legally take the stones.

Think Ahead to Cleaning

One of the more dreaded aspects of owning a garden pond is cleaning it. Garden ponds collect leaves, dust, dirt, and all sorts of debris. Eventually, you need to empty out the pond and clean it.

One way to make cleaning day easier is to create a pond bottom that is smoother and easier to clean. Heavily rocked pond bottoms and those that are heavily textured are more difficult to clean. Lay down only as much rock as is needed to cover the pond liner.

Use an EPDM Liner If Possible

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

EPDM liners resist UV rays well, and 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.

Use a Variety of Terracing Methods

Terraforming the earth below and around the garden pond is naturally the most popular way to give the pond its shape. Earth can be sculpted into a variety of shapes.

But for yards with sandy soil or other earth that doesn’t form so well, it helps to employ other shaping methods. Cans of landscaping foam, similar to insulation foam, are perfect for adding form to curves.

Large sheets of insulation foam can be creatively cut and stacked to provide a garden pond’s basic terraced shape.

Consider the Effect of Sunlight on the Pond

Sunlight creates algae in garden ponds. Moving or angling the garden pond away from sunlight can help to mitigate the problem.

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