Archive for the ‘How to make a really good wildlife garden pond’ Category

How to make a really good wildlife pond: an update

September 19, 2010

In April 2009 I made some suggestions about how to make a good wildlife pond:

– Clean water

– Plenty of shallows

– Focus on the edges: they’re the place where most things live.

Since then, looking at the ponds in my garden and at ponds in Abingdon more widely, I’d add a couple of further observations.

It looks like one of the hardest things to get right is the water plants. It’s not easy to get a variety of native aquatics growing in new garden ponds – which is perhaps why retailers have focused so much on selling us non-natives like Curly Waterweed (Lagarosiphon major, often called ‘Elodea crispa’) which seem to take quickly and easily more or less wherever they are put.

In fact, in most of the garden ponds I’ve looked at there have been hardly any native water plants – with the exception of duckweeds. Unlike the animals, the water plants really are a bit of a disaster area in most gardens.

Our detailed surveys of Abingdon garden ponds also confirm that the best ponds do indeed have the cleanest water. But there are sometimes exceptions: some low conductivity – pretty clean – ponds have poor wildlife communities – look at the bottom left of the graph below.

The graph shows how as conductivity increases (usually a sign of increased pollution) the number of animal species found in the pond goes down. There is an interesting apparent exception.

In the Abingdon survey there was also another pond which, at first sight, appeared to be an exception to the general rule. This pond – on the upper right of the graph (with a circle around it) had a high conductivity and a high number of species.

But this pond is actually a reminder of the limitations of conductivity as a measure of pollution: conductivity is a cheap, quick and accurate way of measuring the total amount of chemicals dissolved in the water, both those present naturally and those added as a result of human activity. It’s often high where water is polluted, so can give us clues about the presence of pollutants but it doesn’t tell us exactly what is dissolved in the water.

In this case, despite the high conductivity, more detailed measurements of the pond water chemistry showed that this pond had pretty good water quality with near-natural nutrient levels. In this case the high conductivity was caused by there being more calcium in the water than in most other ponds in Abingdon.

Added to that the pond had a completely natural base – being dug into wet peaty soil with no liner – so had better margins than most other ponds. It was also the second largest pond in the survey.

So although it appears to contradict the general trend at first, actually it fits the predictions pretty well.

It really does seem to be important to have clean water.

The new pond plus new water

July 13, 2009


Here is the new pond with its shiny new water. Not quite full to the brim: this was 2 and 1/2 water butts full.

Next, clean sand plus clean gravel to be added.

Start again….

July 12, 2009

At the end of April I posted this picture of the recently nearly completed new pond.

The new pond on 26 April 2009

The new pond on 26 April 2009

I didn’t make much progress after that. A hectic spring and early summer – busy with Big Pond Dip, the Blue Peter pond makeover, setting up a new research programme on Water Friendly Farming and a myriad other things meant the pond simply had to be on the back burner.

And in the meantime all was definitely not well with the water quality: the conductivity was much higher than I wanted. By the end of last week, when it reached 320, I decided enough was enough.

So out with both baby and pondwater to start again with new clean water.

So here is the pond reset, just before I added the water (I’m writing this on a train and have realised I didn’t download the last of today’s photos). Anyway, the pond is now re-filled with rain water, from the water butts, and the conductivity is back down to around 85.

The pond before refilling today 12 July 2009

The pond before refilling today 12 July 2009

I don’t really know why the conductivity got so high over the last two months. I have a feeling that when we emptied a tap-water filled paddling pool earlier in the summer onto the lawn some of that water drained into the pond.

So now its time to get on with putting down clean washed sand and gravel to provide a substrate, and to add some locally sourced plants.

How to make a really good wildlife pond (3): the pictures

May 1, 2009

The new pond, finished on 26 April 2009: now I'm just waiting for the rain to finish filling it

This is the full story, in pictures, of the making of my new wildlife garden pond.

I’ve tried to bring together a design which takes account of the many myths that exist about ponds and which have come to dominate garden pond design.

What makes a good wildlife pond is:

– really clean water: this is the most important thing you can do for a wildlife pond.

– plenty of shallow areas: and shallow means less than 5 cm.

– edges as natural as possible: in a garden in practice this means grassy, very gently shelving, and gently varying in depth.

Most advice about garden ponds barely mentions these things. The reason: almost nothing is known about what really makes garden ponds tick. So writers, who abhor an intellectual vacuum, simply make stuff up! Amazingly.

The advice here is based on Pond Conservation’s work on ponds out in the countryside – but even we don’t yet know much about real garden ponds. But we’re learning fast, and the advice below is putting what we do know into practice.

UPDATE: As the pond develops I’ll also be trying to make it look as attractive as possible as well.

Anyway, back to the beginning: the 1st of March 2009 to be exact.


The first cut. I marked the site out with a rope. You can use a hosepipe, string between sticks, bamboo canes – whatever suits you.

For wildlife, the pond shape is less important than the depth (you need lots of shallow water) and the how clean the water is, and what the edges are like.

So ‘natural or ‘formal’: it depends on what looks good in your garden.


Remove the turves: you won’t be needing them again. Don’t put them in the pond! They will almost certainly add a massive blast of polluting nutrients to the water which will plague you for the rest of the pond’s life.


It doesn’t matter when you start or when you finish. I started in March because I had the time then – too late for breeding frogs this year but in time for the main period of warm weather when all kinds of bugs, beetles, mayflies, dragonflies and all the other things are flying about to colonise the pond.


I did a couple of hours digging each time.


By the 11th April I had all the turves stripped off. This took me about 6 hours all together – its slower if you don’t do it all at once. Probably I could have got this far in a long afternoon.

I was fairly confident that the site was more or less level – now it was time to check more carefully.

I needed a piece of wood more than 3 m long to go right across the pond. I didn’t have one at home so had to buy a piece from the local timber merchants for a fiver. I expect you could scrounge something like this for free.


With the spirit level laid on the wood, I could see that the pond was a little bit higher at the back, the side away from the camera.

It wasn’t too much but did mean a bit of fine tuning was needed at the end.


The bubble should be between the two lines

Its very easy to dig a wildlife pond too deep and end up with one of those things that looks a like a miniature version of a giant open cast mine.

A wildlife pond should have lots of shallow water – mine is roughly 50% shallows, and the deep area is not more than 30 cm.

The standard advice that you need to dig down to 50 cm or 60 cm of whatever the writer thinks applies only to fish ponds. The reason you’re told to do this – the pond might freeze solid – might apply in northern Canada, but is simple nonsense in England. The other reason – that oxygen may run out – is probably true sometimes but is not a cast iron rule.

Those of you who read the blog will know that in my first shallow pond oxygen levels rose during the ice cover this winter to double the normal value.

The other problem with digging down this deep in a small pond is that you end up with very steep, or vertical, edges. I’ve managed to get away with having only one ‘cliff’, between the shallow basin and the deep area.

The maximum depth is not much more than 1 spade deep

The maximum depth is not much more than 1 spade deep

Update 2 May 2009. Just saw this comment on a wildlife pond making website:

To assist with water clarity, make your pond as big as possible and avoid a deeply shaded site‘.

There’s no reason to think that either the size or the amount of shade will have anything to do with how clear the water is.

In fact, shaded ponds ae more likely to be clear (less light for algal growth); size really makes no difference.

Anyway, getting back to story, at this point I realised I had a big problem with the edges.


Just in the simple act of removing the turves I’d created a massive steep cliff right at the edge of the pond: the place I was trying to get the gentlest slope.

This happened because its very difficult to dig a turf out that isn’t this 4″ (10 cm) deep because its where the grass roots down to.

There are probably a variety of solutions to this problem.

I chose to raise the turf, remove roughly half the soil from each turf making it half the thickness, and place the spare soil in from the of the turf so making the slope from pond to grass a bit gentler. I don’t think its the ideal solution but it was fairly quick to do.


Now the pond bottom will be at the same level as the bottom of the turf at the edge of the pond.

But the real way to get shallow water in a small pond is have shallow basins.

So this is the final shape: in large parts of the pond, it hardly looks as though I’ve done any digging at all. This is the right depth for pond wildlife.


Tadpoles love shallows: its where they spend a lot of time in my first pond.

Here are my taddies congregating in the shallow warm water they love. This is right in the middle of my first pond: normally the deepest area, in my pond its the exact opposite way round. The middle of the pond is the shallowest area, so shallow it will dry out in the warmer weather. But now its great for the baby frogs, and by the time it dries, they'll proba

Here are my taddies congregating in the shallow warm water they love. This is right in the middle of my first pond: normally the deepest area, in my pond its the exact opposite way round. The middle of the pond is the shallowest area, so shallow it will dry out in the warmer weather. But now its great for the baby frogs, and by the time it dries, they'll probably have grown up and left the pond

Almost all other pond wildlife is happiest in very shallow water as well.

Most garden ponds are too deep for their area: if you want a half metre deep pond, or deeper, it needs to be much bigger or you end up with very steep sides.

The really final shape with turves cur and arranged to cover the liner

The really final shape with turves cut and arranged to cover the liner

The really striking thing about the final shape is just how shallow the pond is: I’m pretty pleased with this, although there’s room for improvement around the edges.

Now the lining: I opted to buy the underlay just for speed – I didn’t have any old carpet around so simply put down a double thick layer of the underlay on sale at the garden centre.

I did remove the stones fairly carefully, but I didn’t bother with sand.

As the total bill for liner and underlay was £134, and as I will have hours of pleasure from the pond for nothing apart from this, I didn’t mind the expense. The liner itself was £90.30. But the resourceful could do it for less.

This is the same approach as I took on the first pond (except there I had a left over roll of underlay I could use from the previous owners of the house).




And then suddenly we’re nearly done: put the liner over the top and add some water to hold it down.


Notice – no hoses. My tapwater is not fit to use in a pond – full of nutrients. In some parts of the country (in the north, for example) its OK where its come off the moors. Down south, its mostly not fit to use in a pond. In most parts of England you can check on the water companies website whether your drinking water is fit to go in a pond – in about half the country it isn’t.

From here on in we have a pond!


Now you begin to see the two halves of the pond.


Now it’s just a case of finishing putting the turves in place, and trimming the liner and underlay.

I didn’t quite have enough water in my water butts to fill the pond completely so now we need to pray for rain – luckily it came the next day.


Everything trimmed up, and the turves all in place. There’s even the first leaves falling in the pond: leaves are a great source of food, shelter and building materials for pond animals.

And finally:


Two months almost to the day (this picture was taken on 27 April 2009) the pond is finished and ready for wildlife to find it.

Its still not quite full: the next day the rain came.


What’s next?

Well, we will add some plants to this pond: local, native, wild sourced plants (only collected from landowners who’ve given permission).

We won’t add ‘pond sludge’: the pond doesn’t need to be ‘started’. We’ve started it simply by making the hole and filling it with clean water, and anyway that sludge is quite likely a source of nutrients from someone elses pond that we don’t need.

We don’t want soil, or turves or fish food or any other of the pollution sources that commonly find their way into ponds. We will have more than enough just coming down in the rain (rain itself is slightly polluted these days).

We will put some clean children’s play sand on the bottom to make the pond a little more natural looking. This is chemically inert so no pollution problems, provided its clean.

And the wildlife? Well that started to arrive on day 1 with little flies laying their eggs, and on day 2 the first water beetles flew in.

The new pond

April 25, 2009


Fast progress today, and suddenly there is a pond.

Now just the tidying is needed, and some rain to complete the filling.

Making my new clean water pond

April 22, 2009
Making progress last Sunday

Making progress last Sunday

The new pond is progressing well – I’ve begun to shape the hole now, and work on the marginal turves. The maximum depth is going to be around 30 cm, with the pond roughly divided between a deeper ‘north’ basin and a shallower ‘south’ basin.

The liner is bought and paid for.

Next weekend should see the final stages, if we are lucky – then it’ll be time to pray for water. No hosepipe filling here!

The spirit level and long pole help to get the margins the same height all the way round

The spirit level and long pole help to get the margins the same height all the way round

More pond myths

April 15, 2009

Five standard pieces of advice about garden ponds from a well-known garden wildlife website. Most are either wrong, misleading or only partly true.

Make your pond as big as possible – this is better for wildlife as there will be more habitats.

This is one of the oldest myths about ponds. The ‘bigger the better’ myth. To double the number of species of animals you see in a pond you have to increase its area roughly ten times. Put another way, the difference between a 2 metre square pond and a 4 metre square pond is negligible in terms of species variety.

To double the number of species found in a 2 square metre pond you have to make it 20 m square. So before worrying about the size there are several other things you can do to maximise the diversity of your pond: make sure the water’s really clean; provide plenty of very shallow water; encourage a wide variety of plants; make sure there are leaves and fallen wood in the water. 

Put it somewhere sunny, away from trees. Ensure some edges are shallow and sloping to allow animals easy access. 

As regular readers will know, my pond is quite shaded and right next to a tall hedge: I noticed yesterday about 1/4 of the pond was in full sun at mid-afternoon. My pond is fine! Full of taddies, thousands of mayflies, backswimmers, newly arrived caddis flies, breeding dragonflies and damselflies, water beetles, naturally colonised water snails.

Having shallow edges is important – even more than this advice implies. Shallow water – very shallow – is crucial in a really good wildlife pond but its tricky to organise. Standard pond designs with their 12 inch deep shelves have virtually no shallow water. 

Stock your pond with native plants from other garden ponds or garden centres. Never take plants from the wild. 

You can stock your pond but I would always get plants from the local wild. Another garden pond is OK if you know your plants, but the chances of getting non-native undesirables is much higher from garden ponds, where these plants are commonest. But isn’t taking plants from the wild wrong? For some specially protected species it is always illegal. For common plants, you need the landowner’s permission, but there is nothing wrong with this. Moving a small quantity of a common plant a short distance (say 1 km) is very unlikely to do any harm. This is how plants spread naturally: carried by birds, grazing mammals, wind and floods moving seeds or small pieces of the plant around naturally.

Far more harm has been done by people buying plants from garden centres which have turned out to be undesirable. If you want to buy plants, check that they fulfil this local provenance rule. And remember, conservation bodies are often pulling water plants out of ponds and wetlands as part of  perfectly sensible conservation work! But never take plants from you local nature reserve (unless they’ve already been pulled out by someone as part of the reserve management plan): a nature reserve is a place where there’s a danger of pulling up something rare or protected – outside of nature reserves this danger is much smaller.

As far as I know, a bit of picking never hurt any of Britain’s water plants: water pollution, draining wetland and filling in ponds have put paid to them.  

Insects, amphibians and invertebrates will find your pond surprisingly quickly on their own. 

Yes – a bullseye! Freshwater plants and animals have the most amazing ability to find little patches of new water – and so they should because they’ve had millions of year’s of practice! So you don’t need to add a bucket of sludge to get your pond started. All this does is means that you miss out on the ‘wow – they colonised my pond’ factor.

Don’t include goldfish; they eat frog and toad spawn. 

The ‘don’t include goldfish’ advice is complicated. Common Toads co-exist with fish – they prefer fish ponds – so there’s no reason to think that their spawn will be eaten by fish. Frogs spawn can develop in larger ponds with fish, provided there is some cover – but if there isn’t shallow water and dense cover for the common frog taddies they will be gobbled up. Toad tadpoles are distasteful to fish: they live with them happily.

The end of the beginning

April 12, 2009

11 April 2009

Well, that’s the turf stripped.

Next – on to shaping the hole.

And a summary of progress so far – each time it was about a 30-60 minutes of work.

1 March 2009

1 March 2009

1 March 2009

1 March 2009

8 March 2009

8 March 2009

22 March 2009

22 March 2009

A garden pond sized Priority Pond

April 6, 2009


This pond is about the same size as my garden pond

This pond is about the same size as my garden pond

This little pond in the New Forest shows that tiny ponds can be important wildlife habitats.

It’s about the same size and depth as my garden pond and we found two species which are endangered in Britain: Mud Snails and Slender Marsh Bedstraw.

This makes the pond a ‘priority pond’: one that should be given special protection because of the wildlife it supports.

The Mud Snail is a so-called Biodiversity Action Plan species and the bedstraw is in the UK Red Data Book.

Both could easily become extinct in this country if not carefully protected.

We also found Palmate Newts and a wide variety of smaller animals in this tiny pond (including an unusual mayfly – more of that another time).

It shows that a pond doesn’t need to be big to be an important wildlife habitat.

Clean water and good surroundings are all it takes.


Vernal pools in New Jersey, USA

March 30, 2009


When you’re making a garden pond for wildlife its good to have some natural ponds in mind for ideas.

This short article from Gloucester County in New Jersey on vernal ponds is a brief intro to the wildlife of these naturally formed ponds – and they turn out to be pretty much like ponds everywhere, whether they are made by people or nature.

Put these co-ordinates into Google Earth to see a vernal pool in Gloucester county: 39°40’53.64″N, 75° 5’20.38″W.

And this is a pretty advanced looking mapping system for NJ vernal pools.