How not to make a pond

I always wanted a pond

Pond when first filled with water.
As long as I can remember I was fascinated by ponds. All that life in the water. Swimming, hopping, crawling around. Even in school I wanted to have a pond.

I decided to write about my experiences in creating a pond, in the hope that other people may learn from what I did wrong. And I did a lot wrong! So much so that my wife suggested I write a book called ‘How Not To Build a Pond.’ Hence the title of this page.

Thirty years later

Pond with stone surround.
Well fast forward something like thirty plus years and one day in the summer of 2013 I took the head stagers as the Irish would say and got my spade out of my garden shed and started digging. Okay it wasn’t just as sudden as that. I had already been thinking about where to dig the pond. I had cleared out a large shrub bed to the right hand side – as seen from my kitchen window – in my back garden. I decided this would make a nice spot for my pond. There was a small Rowan tree in this spot which I wanted to keep and I thought the pond would look nice beside this tree.

So I started to dig. My good sturdy pick also helped a lot with the excavations. I was digging away (while whistling a happy tune – okay I can’t whistle) when my wife asked the important question. ‘Will the tree roots puncture the lining?’ Aghhh.

So down with the spade and onto the interweb for some googling. Well from reading other people’s experiences of building a pond it looked like a small tree was no problem, and indeed a Rowan tree made a good companion for a pond. So back to digging.

I wanted a wildlife pond


My original intention was to have a wildlife pond, frogs etc. So I wasn’t intending to dig too deep. I had also seen enough gardening programs to know that you dug the outer edges shallow and then dig a deeper bit in the middle, all gently slopped. I made the pond circular, seven foot wide, nine inches around the outer edge and two foot deep in the middle. It only took two days to dig the hole and I used the soil to fill in a depression in one of the shrub beds. So far so good. I used builder’s sand, which I already had, to line the hole to cover any stones or sharp ridges and protect the lining.

I then went to the local builder supplies and purchased some lining. This I cut to have significant overlay around the edges, which was the first thing I had done right.

I then turned the hose on it and waited for it to fill up. I had just made my second major mistake, which I shall explain later. I left it all for a day to allow the lining to fit into the shape of the pond. I left all the excess lining and tucked it in under a row of red house bricks which I used to edge the pond. I now just left it for a few days. During these days I decided to line the pond edge, on top of the bricks, with some nice round stones to give it a more natural look.

I knew I needed something in the bottom of the pond to allow plants to root and all that wildlife which I was convinced would populate my pond, to have something to dig / live in. I got some fine gravel (about one quarter to one half inch diameter) and lined the bottom of the pond, to about a half to one inch deep. It all looked very pretty!

I knew enough to know it needed some plants. I had once read a comment ‘A pond without plants is just a hole in the ground filled with water.’ So back to Googling for what kind of plants I needed. Well of course there is the basic staple of all ponds, the water lily. So I ordered one of those. One which was supposed to suit a small pond.

First wildlife


First fish - Black Mirror Comet.
It only took two weeks for the first wildlife to appear in the pond. But it was not what I had expected or wanted. I was looking at the pond one day when I noticed that the water was literally full of little red worms swimming around. More Googling and I discovered these to be Blood Worms. They are midge larvae.

I had this sudden picture in my mind of my back garden filled with flying midges. My wife is particularly prone to being bitten by flying insects. What to do? More Googling and basically the only way to keep your pond water free of midge larvae, or larvae of any kind of insect is fish, which eat the larvae. But I thought that if I had fish I wouldn’t have a wildlife pond. I was in a dilemma. I wanted the pond, so I settled on some fish. Oh well. I purchased half a dozen Black Mirror Comets. In a day the larvae were all gone!

First summer

One of the Black Mirror Comets.
Yes I know it's blue.
The rest of the pond’s first summer was also fraught with problems. Within another couple of weeks the water started to turn green. Algae! This very simple water plant so just too prolific. Everything in the pond was now covered in long thin strings of green algae as well as the water being green. Soon I couldn’t see the bottom and could only see the fish if they came near the surface.

The first thing that occurred to me was to turn the hose on again and flush out the existing water replacing it with a pond full of new clear tap water. Yes it worked great and the water was once again crystal clear. But I just made another fundamental big mistake. I was actually making the problem much worse in the long term. But not knowing that then I carried out the same procedure two more times that first summer.

Solar powered water fountain.
I purchased a solar powered water fountain which works pretty well. The pond is too far from the house to get electricity to it.

First winter

Heron - not mine.
During the ponds first winter one of my biggest problems started. Karen and I were looking out of our kitchen window one morning and there was a Heron, big as life, standing on the side of the pond. Aghhh! It is actually a very sickening feeling.

Now the photo left is not my Heron or my pond, but I've never been able to get a photo, as they seem to be able to sense eyes on them. So as soon as you see them they fly off.

They are beautiful and elegent creatures, but I could have seen my one far enough!

If you have a pond with fish and live in an area where there are Herons, then one of them WILL find your pond. Herons are territorial, so once it finds your pond, it is their pond. They will empty your pond in one morning.

This turned into a battle which would last the next two years and result in me spending a lot of money and time but still loosing at least a dozen fish. By the end of the first winter I had only two fish left.

Second summer


During the second summer the algae and green water came back with a vengeance! More research via good old Google and I had a number of options. First I discovered that I had been doing the worst thing in the world by filling and topping my pond up with tap water. It seemed that the chemicals which are put into tap water actually create the perfect conditions for algae to proliferate. I discovered a golden rule of pond keeping. Never fill, or even top up, your pond with tap water. Always use natural rain water.
100 ltr Water Butt
To help with this I purchased a water butt which I attached to one of my house’s downpipes to use for topping up the pond.
Mussels to help keep the water fresh.
Japanese Trapdoor Snails.
Also to keep the pond fresh.
The other ways to help keep your pond water cleaner and healthier is via mollusks. Namely snails and mussels. So I purchased a dozen large Swan Mussels and three dozen Japanese Trapdoor Snails. The mussels actually were interesting things in their own right. They moved around a lot in the pond, some quickly.
Barley straw.
I also purchased two logs of Barley Straw. These keep down the filamentous algae – the long strings of green which grow on everything. I’ve seen it growing on the shells of the snails. This stuff will eventually choke your pond and your fish if you don’t control it.

Third summer

The pond is now very well established with lots of wildlife. It has four different kinds of snail. The ones I put in, the Japanese Trapdoor Snails, but also Giant Pond Snails, Ramshorn Snails and the one in the image below whose species I don't know.
A new snail which appeared
during the second summer.
Still don't know the species.
Giant Pond Snail
Ramshorn Snail
Japanese Trapdoor Snail

It has leeches, yes I know LEECHES! But apparently this is a sign of a healthy well stocked (with wildlife) pond.
Our resident frog.
He and I have become good friends.
He watches me as I work at the pond.
It has a frog which has been resident since the second summer. It watches me as I work on the pond, following me around the pond, sometimes climbing out onto the edge and following me with it gaze.
Water Beetle.
It has water beatles.
Elodea's delicate white flowers.
Look at edge of Lily pad.
The Elodea flowered their small delicate white flowers.
A Damsel Fly, (small dragon fly)
Which hatched the third summer.
A Damsel Fly hatched this summer.
Limpets on the underside of a lily leaf.
It has a mass of fresh water limpets.
Pond Skaters
The surface is cover with Pond Skaters.
First Lily flower
Bloomed the third summer.
One of the Lilies flowered for the first time.
Pond at three years
With net covering for heron protection.
I hope I have finally beaten the Heron. I have had to resort to contructing a small hence, made of plastic pads around the pond, laying a series of fishing line across the top of this, then laying a pond net on top of that. The net is about eighteen inches above the water surface. You can see this all in the photo below.

In the past three years I've discovered that you can have a wildlife pond and fish. My pond has Goldfish, Koi Carp, frogs, dragon flies, four different species of snails, Swan Mussels, Water Beatles, and numerous other insects all living happily together.


Baby fish!

Baby fish! Goldfish?
At the begining of September of the ponds third year, 2016, I was standing looking at it when I noticed something moving at the surface.

At first I thought it was a large insect larvae of some kind, but on closer examination I convinced myself it was in fact a baby fish!

Then I saw another. Since then I have seen them several times and yes they are indeed baby fish.

My guess is goldfish, but I'll have to wait a little longer before being able to fully identify them.

What I've learnt

So three years on what have I learnt from building my first pond and how would I do it next time if I had to?
  1. Unless you have very defined area restrictions, build your pond at least twice the size you first intended. If you can’t make it wider then make I deeper. At least three feet deep. But only a comparatively small size increase can dramatically add to the pond water volume. If your intending to make you pond the size of mine - seven foot wide and an average of eighteen inches deep, (98,000 liters) just increasing that to ten foot wide and three foot deep, (300,000 liters) triples the water volume. Your pond will be much healthier for it.
  2. Dig out your pond at the end of a Summer/beginning of an Autumn.
  3. Put a good layer of sand all over the bottom. At least an inch deep.
  4. Put down your liner and leave plenty extra around the edges.
  5. Put in your gravel. Go for a gravel diameter of one quarter to one half inch. Put it down at least one inch or even two inches deep.
  6. Put down some bricks, paving slabs or big stones all the way around the edge to keep the lining in place.
  7. Now leave your pond all over Autumn, Winter and Spring until the next summer.
  8. By the next summer it will hopefully be full of lovely fresh rain water. If like me you live in Ireland that will not be an issue.
  9. Now buy your first plants. Water lilies, Elodea for starters.
  10. Let them bed in for a few weeks at least.
  11. Get some fish. I’d recommend a mixture of Goldfish and Koi. I know there is a lot written that you can’t keep Koi in a pond as they destroy their habitat. Ripping up plants etc. I have found that to be completely untrue. They make excellent pond fish. I have two and they have not caused any damage in my pond.
  12. Buy a feeding ring and secure this to the centre of your pond, even if it is out of reach – get yourself a long cane and secure something to the end so you can drop fish food into the ring. This will help keep your fish more in the centre and away from the sides where they are easier pray for Herons and other predators such as cats.
  13. In the past three years I've discovered that you can have a wildlife pond and fish. My pond has Goldfish, Koi Carp, frogs, dragon flies, four different species of snails, Swan Mussels, Water Beatles, and numerous other insects all living happily together.
  14. Heron proof your pond! Buy yourself a good strong pond net and lots of strong pegs. Secure your net at least a foot above the pond surface and make it taught. If you can’t make it taught enough, then buy some fishing line and run strings of this across your pond at a height of twelve inches every foot or so. Then lay your net on the top of this. This will keep the net from sinking down towards the pond surface when your Heron learns it can walk on it, which it will. The only way to stop your Heron from killing your fish is to make it physically impossible for it to make contact of any kind, or even near contact, with the surface of the pond.