How did I create a natural pond in the garden?

Why create a natural pond?

To create a natural pond in its garden offers practically only advantages. But first of all, what is a natural pond? Although it is a stretch of water, it is completely different from the pond of ornament. Indeed, a natural pond is, as its name indicates, natural. In other words, it requires as little human intervention as possible after its construction, as this could unbalance the ecosystem that will naturally take place. Ideally, you should therefore :

• avoid introducing ornamental fish that may eat the eggs of the fauna that you wish to attract, such as newts, frogs and insects of all kinds;
• avoid introducing exotic plants, but favour local plants, oxygenating or not... or simply let nature take its course;
• avoid installing an air pump or a filtration system that could once again break the ecosystem.

You will have understood that with a natural pond, we wish above all to create a balance and it is perfectly what we also seek to do by putting a vegetable garden in permaculture. In addition to bringing biodiversity, the natural pond also makes it possible to water the birds, invaluable auxiliaries, during the heat waves. For my part, I wanted my pond to be as natural as possible, but I also wanted it to be aesthetically pleasing. It is therefore a sort of compromise between a natural pond and an ornamental pond. If you are a purist, you are warned ;-)

Where to create the natural pond in its garden?

The choice of the site of the pond is rather important. Ideally, it is necessary to place it in a sunny place and with the shelter of the large trees. Indeed, when autumn arrives, the fall of the leaves risks creating an aquatic imbalance. This will be even more important if there are fir trees nearby since the thorns will acidify the water. If you have no other option than to install it near trees or fir trees, you can always place a net over it at this time of the year. You will also have to take care of the slope since the edges will have to be level otherwise the water will inevitably escape. As for me, the pond is located at the bottom of my garden near the greenhouse and is exposed to the sun practically all day long.

Which dimensions for a natural pond?

If you have 2 or 3 square meters in your garden, it is amply sufficient to create a pond. Of course, you can make much larger if you wish it, but with these dimensions, you will already be able to attract a very beautiful biodiversity. My pond is about 3m long, 2.5m wide and 80cm deep. This depth is important because it will allow the animals to protect themselves from the cold in winter as the bottom will never freeze. However, this depth should be provided for a small part of the pond and not the whole pond.

In terms of shape, the pond is designed as a staircase because the plants should be placed at different depths. For example, the irises should be placed at a depth of 0 to 20 cm, some oxygenating plants at 20 to 40 cm and the water lilies at 80 cm. This staircase shape allows me to place plants around the edge without the risk of them falling to the bottom. Here are some photos of the freshly dug pond.

What should I put at the bottom of the pond?

If your soil is clayey, impermeable and has a water table close to the surface, you may not need to waterproof the soil artificially. Unfortunately, for most of us, these conditions will not be met and we will have no choice but to install an artificial device: a tarpaulin or pre-moulded pond. I have chosen to use an EPDM liner. It costs less than a hard bottom but it is not cheap (+/- 10€ per m²). However, it is much more durable than a PVC cover. The former has a lifespan of 50 years compared to 10 to 15 years for the latter. Another advantage is that the EPDM tarpaulin can be easily repaired in case of a leak, which is not the case for the latter.

How do I install the cover?

I went to a fish and aquarium store to buy a 1mm thick EPDM cover and I also took a felt pad to put under the cover to prevent stones or roots from piercing it. To calculate the dimensions of the liner according to the size of the pond, here is the formula:

• Length of liner = length of pond + 2 x greatest depth + 1m (for borders).
• Liner width = pond width + 2x deepest depth + 1m (for borders).

According to the dimensions of my pond, the liner is [300 + 2x80 + 100 =] 560 cm long and [250 + 2x80 + 100 =] 510 cm wide. Here are some photos of the felt installation and the tarp installation.

A few tips in passing:

• Make sure that the liner fits the shape of the pond well before filling it. For example, you can place bricks or heavy objects on the sides of the pond to give it its shape and remove them just before filling it.
• Do not walk on the pond liner with your shoes on, but with socks on to avoid damaging it;
• Preferably fill the pond with rainwater if you are lucky enough to have a cistern;
• When the pond is being filled, tighten the liner by pulling on it regularly on both sides to avoid folds;
• Creases are completely unavoidable;
• Fill up to the level of your land;
• Do not cut the edges too quickly as the tarpaulin may shrink slightly. It is better to leave it whole 24 hours before taking out the scissors;

I warn you, for the edges, I've had it! Forgive my vulgarity but I didn't know exactly how to make the tarp as invisible as possible. I finally found a pretty decent solution by digging a small recess around the pond to bury the liner. I then repositioned the "grass blocks" on top.

How to decorate the pond?

To decorate the pond, it's up to your imagination! For my part, I wanted to put in place a small waterfall because there's nothing like the sound of trickling water to relax. So I placed a pump with a low flow rate at the bottom. For the purists, the pond is not 100% natural, but it's my choice because as I said above, I wanted a maximum natural pond but also a little ornamental. This does not mean that it does not attract wildlife. I recently discovered a nice newt in it! For the perimeter, I placed natural stones that I found quite easily along the fields and by asking my contacts. Rather than buying them in the shop, it's a free solution and often does friends or farmers a favour when they want to get rid of them. Here are a few pictures of the almost finished pond.

As I write this article, I have not yet planted anything around the pond. I'm considering a flower meadow for this year, and I'll see what to do this fall. There's no rush!

How much does it cost to create a pond?

It's hard to answer this question because it depends on the materials used. Nevertheless, here is what it cost me to create my pond:

• elbow grease since I had to dig out a good twenty wheelbarrows;
• 300€ for the felt and a quality EPDM tarp;
• 15€ of gravel and 0€ of stones;
• 50€ of aquatic plants;
• 30€ for the pump;
• 0€ of water since the 2 cubic meters of water come from the rainwater tank;

I hope this little review has given you some ideas. Don't hesitate to share your experiences, questions or remarks in the comments! =)