How to Build a Garden Pond

Written by Kevin Espiritu Horticulture review by Sarah Jay Last updated: October 28, 2025 | 2 min read

A close-up shot of a man-made puddle, placed alongside plants and flowers, showcasing how to build a garden pond

Contents

Getting a landscape gardener to build your free-form pond can be expensive, so follow the steps below and get the satisfaction of doing it yourself.

Choose Your Location

A shot of a large, sunny, landscaped backyard area near a home — Select a site where it will get plenty of sunlight.

Site your pond where it will get plenty of light, with some direct sunlight to help plants grow. Avoid placing it near deciduous trees, otherwise you’ll spend a lot of time removing dead leaves from the water.

Dig the Hole

An overhead shot of a dug out hole beside a wheelbarrow, all situated in a yard area outdoors — Mark out the shape before digging out to shelf level.

Mark out the shape of the pond with pegs & string, or chalk. It will need to be 90cm deep in the centre, if you’re keeping fish. It will also need a shelf for marginal plants, and to allow frogs and other creatures to get out. Using a spade, dig out to shelf level (15cm). Next, starting 15cm in from the sides, dig out the rest. Check the sides and bottom for large stones or sharp objects which could rip your liner.

Line the Pond

A close-up shot of a person in the process of placing a liner on a small dugout hole, all situated in a well lit area outdoors — Line the bottom with thick blankets, carpet underlay, or a proprietary under-liner.

Put a 2-3cm layer of sand on the bottom, then line the entire pond with thick blankets, carpet underlay or proprietary under-liner, so that it comes over the top slightly. The under-liner should be 2-3cm thick. This can be trimmed later, if necessary.

Insert the Liner

A close-up shot of a black colored liner on a dugout hole in a yard area, all situated in a well lit area outdoors — Lay the liner on top and gently push down, positioning it so the liner reaches every part of the hole.

For a pond that is 90cm deep x 180cm x 120cm, you would need a liner measuring at least 4.5m x 4m. Lay the liner on top of the pond and gently push down. It’s easiest if you get into the pond but take your shoes off. Now position the liner so that it reaches into every part nook and cranny, paying particular attention to the shelf. Leave some pleats, as the liner will expand when filled with water. Ensure there is a minimum of 30cm overhang, which can be trimmed and hidden, once the water goes in.

Border

Once the pond is full, you will need a border to hide the liner and make the pond more attractive. You can use bricks, slate, cobbles or stone slabs. If you’re using slabs, you will need a grinder to cut to size, such as those sold by Anglia Tool Centre. Ensure you wear goggles and a mask. Once your border is positioned, preferably with a slight overhang, trim off any excess liner and secure the stones with mortar. Even heavy stones can end up in the pond, tearing a hole in the liner, so make sure they’re solidly embedded.

Wait at least two weeks before adding any plants or fish to the pond, to allow for the chlorine to dissipate. You can also buy additives to speed up the process.

7 Invasive Weeds to Remove From Your Pond Now

Prevent your backyard pond from getting overgrown with invasive aquatic weeds through early detection and quick removal. These aggressive pond weeds can easily take over, harming water quality, fish, and aesthetics. Here are the 7 most common species to look out for.