How to make a wildlife pond

The trick to hiding the pond liner is to buy extra felt underlay and lay this over the butyl liner. You then add a thick layer of subsoil from the bottom of your pond hole (about 10cm) over the underlay, and plant directly into it. Subsoil has fewer nutrients than topsoil and is therefore less likely to cause problems with algae, which feed on water nutrients, later on.

Over time, the plant roots will knit together and stop soil erosion, but the water may be muddy for a few months. Don’t worry – this is perfectly normal.

Initially, before the pond settles, the water may turn green. Algae feeds on nutrients in the water, which will eventually be absorbed by plants as they grow (using subsoil to line the pond will help reduce the likelihood of this being a problem). Green pond water is nothing to worry about in the short term, and should sort itself out as the pond matures, but if you get blanket weed, you can remove this with a bamboo stick, twirling it around as if gathering candyfloss. Place the blanket weed in a bucket of water and swill it around to dislodge any trapped wildlife, which you can then return to the water. Duckweed can also be dealt with in this way.

For the healthiest pond, aim to have plants growing across about two-thirds of the water’s surface. Remove leaves and other detritus each autumn, and add more subsoil if the underlay becomes visible at the edges.

The key elements of a wildlife pond

• Shallow areas, where frogs can spawn, birds can drink and bathe, and hedgehogs can drink safely
• A dragonfly perch, which male dragonflies will use to patrol the area. Use a large stone, log or a long stick pushed into the ground, avoiding puncturing the pond liner
• A beach area made from stones, which will stop plants growing at the edge and give you a clear view of bathing birds
• A good mix of oxygenating, floating and submerged plants, plus marginals planted around the pond edge. The more plants you have, the healthier your pond will be, and the more wildlife it will attract
• Hiding areas around the pond. These could include a pile of stones, logs or dense plantings of low-growing plants that could shelter wildlife, such as froglets, when they emerge from the pond

You Will Need

• Length of hose for measuring
• Garden spade
• Spirit level
• Piece of timber
• Fleece underlay, plus a second layer of underlay to place over the butyl liner
• Butyl pond liner (use an online pond liner calculator to determine how much you need)
• Subsoil from the hole you've dug
• Pond plants such as brooklime, water forget-me-not, hornwort, spiked water milfoil, frogbit, water soldiers and marsh marigold
• Pebbles, stones and logs

Step 1

Use a hose to create the shape of your pond on the ground and then dig. Aim for a depth of 45-60cm in the centre, graduating to 30cm near the edge. Keep the subsoil to one side to use later. Check the sides are level using a piece of wood and spirit level.

Step 2

Lay the underlay in the hole, tucking it into the corners, especially in the deeper area. Where necessary, fold over and weigh down with smooth stones. Take off your shoes if you need to walk on it. Then, still with your shoes off, lay the butyl liner over the underlay. Smooth out any creases and fold over where necessary, but try to keep folds to a minimum. Use the stones that you used to secure the underlay to now secure the liner. Check the liner totally covers the underlay.

Step 3

With your shoes on, lay a second layer of underlay over the liner. It helps if the underlay is a different colour to the liner so you can properly see what you’re doing. It doesn’t matter if you have to lay the underlay in strips – just make sure you can’t see the liner.

Step 4

Use a spade to add a thick layer of subsoil over the underlay and firm with your feet. If the soil is too dry, wet it a bit, but avoid wetting it too much as this job can quickly become messy! Make sure the mud completely covers the underlay.

Step 5

Take marginal plants, such as brooklime and water forget-me-not, from their containers and gently tease apart the roots. Plant portions of them directly into the mud, all around the edge. Pack the plants closely together.

Step 6

Now it’s time to add water, while trying not to dislodge any mud. If you can, use rainwater from a water butt. But if you can’t do this then tap water is fine, but as tap water contains more nutrients than rainwater, you may find you get algae forming until the plants have grown.

Step 7

Add stones and logs to the edge of the pond to make a beach. Add oxygenating plants, such as hornwort and spiked water milfoil, to the water. Finally, cut the excess liner and underlay from the edge of the pond. Use more mud to hide any last bits of liner.