What You Need to Build a Garden Pond

A garden pond is a small oasis in your backyard. Serene and blue-green, a pond is not only a pleasant point to meditate upon but also a popular hangout spot for frogs and birds. If you want to add an aquatic element to your backyard and keep fish free from the confines of a tank, creating a garden pond could be your next big project. Wondering how to build a garden pond? You’ve come to the right blog.

Before you even begin building your pond, it’s important to get your ducks in a row. Much like a paddling duck, a pond will usually look tranquil but have a lot going on beneath the surface. From its carefully curated measurements to its pump and filtration systems, a pond is a deliberately crafted construction made in the image of its intended purpose. Let’s dive straight into the technical specifics!

Forming the Foundations with Pond Liners

The liner is the skeleton of the garden pond — the underlying structure that no one sees but keeps everything in place. Specifically, it’s an impermeable geomembrane that retains the pond’s liquid and helps hold its shape. Pond liners come in varying sizes, and you should choose one that corresponds to the size and shape of the pond you want to build. You should also account for an extra 50 to 60 centimetres on each side, as this will give you a 30- to 40-centimetre depth and a 10- to 20-centimetre overhang.

Edge design will also inform your blueprint. After all, once the pond liner is anchored to the ground, you’ll want to do away with its unsightly PVC edges. There are a few ways to treat edges, ranging from simple to elaborate. Here are some of our suggestions.

Bog Garden

If you fancy a spot of gardening, you’ll relish the opportunity to garnish your garden pond with a touch of greenery. Close off your pond’s edges with sturdy stone to create a waterlogged pocket — and then fill that pocket with (low-nutrient) soil to support moisture-loving plants. Voilà! Your PVC edges have sprouted anew.

Waterfall or Stream

To create a waterfall or stream, start by laying your liner wide so that it extends into the pond. For added protection, consider double-layering the liner with an extra liner sheet or a shade cloth. Once your foundation is in place, add a layer of sand or mortar to cushion the surface. Finally, arrange your rocks and pebbles to shape the flow of water, ensuring a natural cascade into the pond.

Edges of Stone

Form a level shelf with your pond liner to support stone edging. If you think this idea rocks, double up on the pond liner or add a layer of shade cloth to ensure the stone stays where it is and doesn’t interfere with the pond foundations.

Pebble Garden

Lay your edges to form gentle slopes: the perfect foundation for a garden of rounded pebbles. Consider adding a layer of shade cloth to protect your pond liner from punctures.

Sandy Beach

Form gentle slopes to simulate the eroded ground of the beach, and watch that beach come to life when you cover it in sand. Before you pour, make sure to either prepare a 50-millimetre sand bed or insert a liner underlay beneath the pond liner.

Other Essential Pond Components

Pond liners may inform the shape and size of your pond, but there are other garden pond essentials you will need. We’ve touched on the importance of an underlay — but as well as supporting ‘sandy beach’ edging, it can also be quite important for protecting your pond liner’s base surface area. Made from fabric tough enough to prevent tears from rocks or nearby tree roots, an underlay shields a pond liner by sitting underneath it.

Do garden ponds need a filter? Yes — and especially if they’re housing fish. Without pond filters, water quality will go way down, tainted by algae and debris, fish food and faeces, and ammonia and nitrates that can stress fish out and make them more vulnerable to disease. While aquatic plants will add a layer of natural filtration into the water, they’re no substitute for artificial filters, which work around the clock to process larger volumes of water. Just as aquatic plants will almost always need some form of anchoring — our favourite is rocks or gravel — filters will usually work in tandem with pumps.

Does a Garden Pond Need a Pump?

Yes, a fish pond pump is almost always necessary if you want to purify a pond properly. Pumps circulate pond water rapidly and facilitate filtration by propelling unwanted particles towards the filter. With a pump, the filtration process ‘just keeps swimming’; without a pump, the water will likely stagnate and accumulate algae.

Which Pump?

Selecting the right pump depends on your pond’s size and water volume. A general rule is that your pump should circulate the entire pond’s volume at least once every two hours. For example, a 4,000-litre pond requires a pump with a minimum flow rate of 2,000 litres per hour. Pumps come in submersible and external models, each suited to different pond designs. As the name suggests, a submersible pump works overtime underwater, pushing the water directly into the filtration system. On the other hand, an external pump is mounted to the pond’s exterior, drawing water in through an intake pipe. While submersible pumps work best in small- to medium-sized ponds, external pumps better suit large ponds because they handle higher flow rates more easily.

Which Filter?

There are two main types of fish pond filters — mechanical and biological — and you can use both to ensure your pond is crystal clear. Mechanical filters are like rubbish collectors that remove physical waste (debris, fish faeces, and leaves), while biological filters are like probiotics that introduce beneficial bacteria to eliminate harmful toxins (ammonia and nitrites). You can also implement algae-busting UV clarifiers into your pond. While pumps should keep water moving and algae at bay, introducing UV light into the pond can kill any lingering algae spores, clump them together, and send them off to the filter.

Put It All Together & You Have a Garden Pond

Building a garden pond is an involved process. It starts with forming foundations from a pond liner, continues with obscuring the edges with an aesthetic treatment, and finishes with installing a pump and filter for your plants and fish. Take the first step today — take those measurements that will inform the dimensions of your garden pond. When you finally need a pump and filter, you need only return to Aquarium Kingdom to find the models you need. It’s time to get started!