Tiny City Pond Help

[samoht]

Hi all, so I've decided to try and fit a pond in to my small city garden and I'm looking for opinions about how small it really can be.

We don't have a big space and we've already got wildflower patches, a bedding area with seasonal flowers, bushes and log pile, a tree, a shed and we have a dog who needs to play on some grass.

This all doesn't leave us with much room and the only place we can squeeze a watery patch in is down next to the fence, near the shed and tree, not ideal, but its the only space left.

So I measured it out and it will be about 190 cm long (give or take) and only 70cm at its widest. From what I've read I need to make sure it is deeper than 90cm to avoid freezing completely. Does this small size sound even feasible?

We're not putting any fish in, its solely for attracting insects and if any frogs do happen to be on a city break.

[mickmassie]

I'd certainly go for it, many interesting ponds are no bigger and any pond is much better than no pond. 90cm deep sounds very deep to me, few garden ponds are that deep. M.

[Tursiops2]

Hi samoht, welcome to the forum

Sounds like a good set-up, but 90cm is much deeper than necessary. The minimum maximum depth (if you see what I mean ) usually recommended for a wildlife pond is about 60 - 70cm, but for a small feature like yours, this is too deep to allow for shallow sloping edges. Unless you're in the far north, UK weather is rarely cold enough to freeze to that depth. The greatest biodiversity is in shallow water, and in a small pond, water over 1m deep is effectively ecologically redundant.

If you're not keeping fish, you can get away with 40-50cm, possibly even less.
T2

[ilia123]

I think this is quite a good read:

http://xexexexexexexexexexexexexexex...d-garden-pond/

Edit:

Hmm not sure why my link doesn't work but it was a link to Biggs' Pond Blog:

Clean water is key

Really clean water is essential for making the best wildlife ponds. One of the great things about gardens is it’s possible to make ponds which are actually cleaner, and less polluted, than most ponds in the countryside.

Many people fill their new pond with tap water. This is a bad idea because, even though tap water is safe for drinking, it’s often not clean enough for your pond! And for the best wildlife pond don’t add soil, or fish food, or fertilizers or upside down turves – indeed anything that adds nutrients or other chemicals in unnatural concentrations to the water. The pond doesn’t need them.

To fill the pond it’s best to use rainwater – you can collect this in water butts. If you happen to have a stream flowing through your garden – avoid using the water from it! Away from remote mountain areas it’ll probably be polluted, and will pollute your pond.
Natural edges and shallow water

If you have really clean water in a pond it doesn’t much matter what shape or depth it is – it will be have great potential as a wildlife habitat. But natural ponds have natural edges and most of the wildlife lives in the shallow water at the edges of the pond, in water no more than an inch or so (2 cm) deep. This is really shallow, half length of your little finger!

And unless you’re keeping big fish, the water needs to be no more than a couple of feet deep (say 50 cm) in the middle. In those shallow edges let grasses grow, or maybe low growing marginal plants that can trail into the water.
Let wildlife come to your pond naturally

People often add a bucket of sludge to ‘get the pond started’. But there’s no need to do this if your pond is clean and natural – animals and even water plants will colonise naturally (though plants may take a year or two). And if you can resist the temptation to add things you will have that thrill of seeing animals, and maybe plants, arriving under their own steam.

And remember that new ponds are not ‘empty’ but a special kind of habitat – the place where the plants and animals that like bare sediments and no competition can live for a short time – until the pond becomes more mature.

If you can’t resist adding plants get them from somewhere nearby – a local pond, river or stream. Remember you can pick common plants with the landowner’s permission, but stay away from nature reserves that may have specially protected species which it is never permitted to pick. Try not to move things further than a wandering cow or pond hopping duck might move them.
Really shallow water is great for wildlife

Most garden ponds don’t have enough shallow water. The greatest variety wildlife in ponds lives in the very shallow water and tadpoles, newt larvae, water beetles, dragonflies: all love these really shallow areas. A planting shelf that you see on many pre-formed liners is, as far as wildlife is concerned, deep water!

Make as much shallow water as you can for the best wildlife ponds.
What about fish?

Fish are a natural part of the wildlife of bigger ponds but too many fish in a small pond is bad news for almost everything else.

A pond with ornamental fish won’t be totally lifeless but there’s not much chance of seeing the range of wildlife that lives in a clean, natural pond – unless you’ve got a huge garden, and can make a very big pond. So if you’re keen on fish, we recommend that have two ponds: an ornamental pond for your fish and a second pond for wildlife.
Should I add plants?

Almost everyone adds plants to their ponds – but natural ponds can colonise perfectly well without this help, and recently we’ve realised that garden ponds can also colonise naturally.

Plants are a natural part of pond’s wildlife and they provide habitats for animals: somewhere to lay eggs, somewhere to feed and a place to live.

The most natural ponds have a mixture of emergent, floating-leaved and underwater aquatic plants. With a good clean pond you can get all of these in your pond too.

If you want to buy plants make sure that you don’t accidentally bring along unwanted non-native species at the same time – many of these have escaped from garden ponds and are causing a lot of damage. Here is a list of plants to avoid.

and finally….
Your pond is not a bath – you don’t need to scrub it clean!

The best wildlife ponds naturally have sediments, fallen leaves, twigs and branches on the bottom and plenty of plants in the water.

You don’t need to pull these out to keep your pond in ‘good condition’. They are the habitat of animals in the pond – if you do clean them out, you pull out the animal’s habitat as well.

Check out his blog, I found it rather informative.

Here is an article regarding the depth question you ask:

Well, the first thing to say is that nobody has ever actually looked carefully at a variety of different garden ponds and their wildlife to know for sure. But we’ve just had the coldest weather in the UK for about 20 years which might give us some clues about the need for a pond to be, say, ¾ of a metre deep (75 cm – that’s a pretty deep pond!) for animals to survive freezing over.

In my pond, there’s little sign that the cold snap, when we had ice cover for about 2 weeks, had much effect on the dragonflies, mayflies, beetles, bugs and the like – the invertebrates. The dip yesterday showed a full complement of the beasts that were there before the cold weather. I don’t known whether frogs hibernated in the pond – but I certainly haven’t had any dead ones, and there was so much oxygen in the pond that there was no danger of frogs suffocating.

But quite a few other people have had frogs which presumably ran out of oxygen. I’m guessing these were ponds where the dissolved oxygen was much lower anyway – my neighbours Sally and Adrian, for example, have a pond where there was only just enough oxygen to keep things going under the ice. Frogs in their pond could have been in a much more precarious situation (luckily they didn’t have any casualties).

The theory is that a deeper pond is, the more ‘stable’ it is: so it won’t freeze solid, and will also have enough oxygen to tide animals over. Does this happen in practice? Well, my own pond shows that you don’t need a particularly deep pond to keep the dissolved oxygen up, or to avoid compete freezing.

In my case I suspect the shallowness of the water may have helped with the amazingly high oxygen concentrations by allowing oxygen producing algae to grow on the pond bottom. The very clear water and large amount of moss growing under the water probably also helped.

And as for freezing solid – in the south of England after the coldest weather for years there was a couple of inches of ice on the water – there was no chance the pond would freeze completely solid.

My pond is 25 cm deep in the deepest point, about the depth of a Wellington boot – this looks a pretty good to depth me.

For the size of pond this is also much more like the depth of many naturally formed pools – always a good guide to what’s the right design for wildlife.

[Kayleigh]

you could always make a barrel pool like this one.

[samoht]

Hey thanks to everyone for such quick responses already.

Those guides were really useful and your positive views is encouraging. I've bought the lining and we'll be a-digging before the end of the week. Its exciting.

I'd got the 90cm depth from reading around online, so its good to know I don't need to worry about it going that deep. We're right in the center of London anyway, so (apart from this year) long freezing spells are rare.

It'll mostly be much shallower and sloping as its going to have to be close to our tree, so I'll have to dig shallow to avoid its roots.

Additionally, with all the recent rain our waterbutt is full, so we won't need any tap water to get it started.

Thanks again.

[ilia123]

Originally Posted by samoht

Hey thanks to everyone for such quick responses already.

Those guides were really useful and your positive views is encouraging. I've bought the lining and we'll be a-digging before the end of the week. Its exciting.

I'd got the 90cm depth from reading around online, so its good to know I don't need to worry about it going that deep. We're right in the center of London anyway, so (apart from this year) long freezing spells are rare.

It'll mostly be much shallower and sloping as its going to have to be close to our tree, so I'll have to dig shallow to avoid its roots.

Additionally, with all the recent rain our waterbutt is full, so we won't need any tap water to get it started.

Thanks again.

That is good news. Clean, shallow water, with a very gradual sloping bank is the key to a great pond.

I think you will have lots of fun!

If you google "The Garden Pond Blog" you should get the blog even though my links don't work - lots of interesting information to go through there!

[samoht]

Thanks again.

The pond is now dug and filled, I think at its deepest its 60cm, but that's only right in a dip in the middle, mostly its between 10-20cm deep. I've put mud on the bottom and created a boggy area out of one of the shallow ends. I've also built a couple of very mini rockery patches and when I find suitable rocks I'll build a little cave like structure with the top rock sitting just out the water, should anything ever wish to sunbathe....

I'd like to put a couple of aquatic plants in, nothing too ambitious, but certainly something reedy around the edges would look nice, any good stockists that you know of for native plants? I don't really like the idea of trying to take stuff from the wild.


If I aimed for something reed-esque in the bog shallows, would anything in the deeper areas be useful? Would a flowering lily type of thing be too much?

So many questions...

[mickmassie]

Sounds great, well done.
Most aquatic plants will replicate very rapidly given some clear water and lack of competition so take care. You'll be removing mud very soon as it builds up if leaves etc are allowed to fall in. Lilies will swamp the whole place if they are allowed to, so get a small variety if you are buying.
Callitriche is a modest plant and Mare's Tail Hippuris gives nice emergent shoots. Potamogeton can be got in a wide variety of forms.
Brooklime has to be cut back vigourously in my pond. Water mint and Gypsywort make a nice surround if you have a damp edge
M.

[Stevelphoto]

For native plants, try puddle plants. There is a similar thread a few threads down from this one, with suggestions for which native plants to try.