As fishkeepers, have you ever wanted to give something back to the wild? Jeremy Gay explains that you can, and you can do it in the comfort of your own garden.
Our aquatic addiction makes us nature lovers by default. However, our eco-credentials are difficult to defend with all the single-use plastic, air miles and energy consumption.
Fish conservation work is not feasible for many of us, but there is another way to help the planet’s wildlife. Build a wildlife pond.
Building a wildlife pond is just about the most eco-friendly aquatic project you’ll ever embark on. They are cheap, easy, and don't use any electricity as nature ponds don't require filtration. Plus, they have a positive impact on wildlife, the environment and maybe even your wellbeing.
A wildlife pond provides a haven for aquatic and terrestrial life. These garden ponds can also be attractive feature in the garden and can be educational.
Related article: Brighten up your garden pond.
Little and large wildlife ponds
Wildlife ponds can range from washing up bowls to lakes, and any water in the garden is better than nothing. Aesthetically, all ponds shrink when you add plants to the edge of the pond. A small pond is typically less than two metres wide, while ponds between two to four metres are medium-sized.
The larger the pond, the more biomass of plants and animals it can support. So bigger is actually better. If you can, aim for a pond measuring at least a metre wide.
Unlike a standard fish pond, deeper isn’t necessarily better with a wildlife pond. Our imported pond fish need a water depth of over 60cm (24"). This enables them to hibernate in the 4°C (39°F) thermal layer at the bottom of a pond if it freezes over. Ornamental carp like koi need even deeper water of at least 120cm (48") to exercise and develop the right body shape and grow.
Experts have found that the greatest abundance of life in natural ponds inhabits just the first 10cm (3.9") of water depth. So for a wildlife pond, depth is rarely an issue, saving you from a lot of digging.
You can go deeper than this, but ensure a large area of the pond is a shallow, gradual slope. Shallow waters do risk freezing, but our British native species survive these cold winter cycles just fine.
No flow, no features, just as nature intended. Photos by Shutterstock.
Where is the best place for a nature pond?
Water collects at the lowest place in the ground so if you have a natural dip in your garden that’s a good place to plan a pond. The most productive natural ponds are solar-powered. Few trees grow in the lowland marshy wilderness to provide the waters shade.
Therefore, it is fine to position a wildlife pond in full sun, as pond plants can then proliferate, locking up carbon and nutrients. Also, the pond edges will warm quickly, making them perfect for tadpole development. Natural ponds also occur in shady forests, but you’ll note the lack of aquatic plants growing there. They are less productive as a result.
Shallow ponds in full sun are everything we say not to do with a fish pond. However, wildlife ponds and fish ponds are like chalk and cheese, with most of what we think we know about a healthy pond turned on its head.
Keep it grounded
Forget what all the books, websites and gardening programs tell you; a wildlife pond must be at ground level. Creatures must be able to crawl in and out, from insect larvae to newts, froglets and hedgehogs.
Build a ‘wildlife pond’ in a half whiskey barrel and the only wildlife thriving, as a result, will be mosquitoes. And it has to have ease of exit too otherwise you risk drowning wildlife. Even frogs can drown in ponds with steep, vertical walls. Another reason that a wide shallow incline is ideal for ponds with deeper areas.
Frogs require an easy entrance and exit to and from the pond.
Build a beach
You can fill shallow areas of nature pools with pebbles, aquatic compost or even aquarium sand. Pebble lined ponds can look artificial to some but British wildlife seem to love that shallow transitional pebbled area.
And as a wildlife bonus, those stones warm up in the sunshine forming basking areas and staying warm long into the night. Plus, by virtue of our pond not containing any fish, there is nothing to stir up a soil or sand area.
Related article: How to avoid summer pond problems and how to solve them.
Digging a nature pond
A spade is all you need to get started but if you have one, use a spirit level too. The aim is not to have any pond liner showing at the end. Make sure the area you dig has a level edge so that you don’t have a chunk of exposed pond liner at one end. If there’s a lawn there, dig up the turves and save them for later.
Dig the pond so that it is like a satellite dish in profile or a wedge of cheese. It doesn’t need to be round, it can be any shape as long as the edges are shallow for wildlife to enter and exit. Work out where the sun will hit the pond and try to make the beach area south facing to receive maximum solar radiation.
You don’t have to create that one deep area in the way that you do for fish and filter pumps. Instead, you can be brave and create an island or sand bar in the pond. The more habitats and features you create, the more versatile the pond will be for the myriad of wildlife. Make a mini, natural Center Parcs for aquatic life and they’ll instinctively want to holiday there.
Once dug, rake it to remove any sharp stones and if there are trees nearby, chop the roots back so they don’t pierce your liner in the next few years. You can then line the ground with sand or purpose made underlay to help protect the all-important pond liner. Underlay is inexpensive so invest now, set it and forget it.
Without fish, you have a wide range of options to create a bank at the end of the pond.
Pond liner basics
Use a pond liner calculator to work out the size of pond liner you need to create a pond. Liners are available in a range of materials from a classic PVC to a durable rubber. They also come in different thicknesses, and with varying guarantees. If you can afford it go for the thickest liner, with a lifetime guarantee — especially for large ponds.
If you’re on a budget and want to keep project spend right down, PVC pond liners are just fine for smaller ponds and a small 2x2.5m (6.6x8.2') sheet may cost less than £20. That’s incredible value when you compare it with aquarium projects.
Choose a sunny day and, using two people carry it like a bed sheet, place it down gently over the hole.
As you’re initially filling the pond with water, stretch the liner to iron out any creases. Pin the edges down with stones. Trim the liner all around so it has a 12” flange around the outside.
Dress the edge with stones, logs, pebbles, the turf you saved from earlier, or a mix of all four for maximum habitat diversity. Cover up any exposed liner to achieve the most natural effect. Lay a fallen branch down into the water, as this looks awesome and is a perfect perch for dragonflies.
Now you can start working out which plants you want to add to your pond. This is down to personal preference, mostly, but we have some tips available to help you decide on your next steps.