How to build a wildlife pond.

Customers who are about to build a pond often phone me for advise, asking things like “Should I add plants to my pond?” “How do I increase the wildlife?” “Do I need a filter?” “How do I help prevent algae?” So I thought I would put together all the information I have on the subject, hopefully helping anyone who is about to build a pond. Now in my experience a wildlife pond is a lot easier and less costly to look after than a fish pond.  Fish are predators and eat tadpoles, eggs, tiny frogs and other water creatures. However lovely fish are, they do produce excrement daily and this, along with their food, pollutes the water and feeds blanket weed and the type of algae which turns the water green. A well thought out and looked after wildlife pond can bring a haven of life like dragonflies, pond skaters, snails, newts, frogs, garden birds, bats, badgers and waterfowl.

So, where do you place your pond?

Think about, space, size, depth, and light and be sure there are no utility pipes in the area you are planning to dig. Do you want to keep things small with just a half barrel or water feature, or a larger pond with possibly a stream, waterfall or cascade? Still water can become stagnant and flowing water is good for oxygenating the water, but building a stream is a lot more work. If you place it directly under a tree, although the shade will be beneficial you will be forever fishing out leaves. Leaves turn into sludge which pollutes the water causing algae to thrive. Ideally the pond needs some light so that the aquatic plants are happy, but also some shade as algae loves the sun.

Now, it’s time to get your hands dirty.

How to build a pondOnce you’ve chosen the best position, mark out the desired edge with a piece of rope and dig to desired depth. The deeper the better, 45cm (18″) or more, the deeper the pond the more wildlife. Set aside some soil and turf if you can, you can then use this later when tidying up your edges. Have sloping sides, shelves, nooks and crannies for wildlife to live on. The edges should be no deeper than 5cm (2”) so that thirsty hedgehogs can get out easily if they fall in. Remove sharp stones then layer the bottom with one inch of sand to stop any damage to the liner. You can also use newspapers, cardboard or my favourite is old carpet if you have any.

Use a spirit level if you have one to ensure the surface of your pond is horizontal.

Lining your pond

I recommend you use a pond liner rather than a pre-formed shell, I find the shells very tricky to fit and using a liner you are flexible to shape your pond exactly how you wish. Don’t scrimp on a cheap liner; the last thing you want is a leek.

Calculate your liner.

Length of liner = Length of pond, plus twice its depth and add 10%

Width of liner = Width of the pond, plus twice its depth and add 10%

When filling pond if possible use water from a water butt or better still allow to fill naturally with rainwater. Tap water is high in nitrates that foster the growth of algae.

building a pond

Weigh down edges with stones and start filling, move stones while filling, shaping with your hands. Once filled, you can cover excess liner with the soil and turf that you set aside earlier. Also add a thin layer of sand or soil on the bottom to help prevent the liner being broken down by the sunlight. There is a good selection of pond liners available online at Bradshaws.

If you decided to build a stream, waterfall or cascade.

Split your area into a higher ground level and a lower ground level.

Dig out your trench marking first with a rope. Remember you will be adding stones or gravel so make it deep enough for this. Also consider the route of pump supply hose.

If you want a waterfall effect you can make it steeper with steps or gradual for more of a stream effect (ensure it is steep enough to let the water run smoothly.) You can use cement, but make sure the cement is fully dry before filling. When building steps, each one should be at an angle slopping backwards, so creating a pooling effect. You need a strong enough water pump to pump the water up from your lower level to the top. Lay your liner with plenty of overlap so avoiding water loss, you can hide the excess with soil, stones or slate can look very effective. I like to use river pebbles on the bottom rather than gravel as they are less likely to be washed away.

Maintenance and Making the pond look attractive.

You shouldn’t need a filter unless you have fish, however, oxygenating plants are vital as they create shade and help to keep the pond clean and healthy. Also, toads, newts and frogs hide under their leaves.

How to build a pond

Plant the margins so that they look natural.  If you have any spare rocks, rockeries are making a come-back. They not only look very pretty but they also create essential places for wildlife to hide from predators such as cats and birds.  To prevent blanket weed, green water, sludge and algae from taking hold, apply Aquaplancton in spring summer and autumn.

Please see our application instructions for more help with this.

And Finally Safety

Even shallow water can be a hazard for young children, so if you have any in your family you can cover the pond with a heavy duty sheet mesh. Once everything is taken care of, sit back and enjoy the fruits of your labour, the wildlife will certainly appreciate everything that you have done and you will be rewarded with their presence.


Sara Ellis


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