When we open our garden for charity on the National Garden Scheme one thing people always comment on is our micro pond with its miniature pink waterlily. Ponds sound complicated but actually they’re really easy and none are easier than a micro pond! Here (and in my book A Greener Life) I’ll explain how to set one up and why it needs practically no maintenance.
How to make a micro pond in a pot
To create a micro pond you just need something to hold water that has a minimum size of 60cm diameter and 40cm depth, enough to hold a minimum of 30cm of water. 30cm gives most plant life enough space to grow – if you choose the right plants.
What container to use for a micro pond
Any container will do, you just need to make sure it is totally water tight and won’t leak water gradually. For instance, a terracotta pot that isn’t glazed is porous and so water gradually will seep out. Obviously any holes are a problem. The best containers are made of metal, glazed terracotta, polystone, fibreglass, non-porous stone like granite or marble and plastic. You can have these pots on a hard surface raised or even sink them below ground like a normal pond in miniature – where Butyl pond liner will be fine and cheap too.
I spent a long time choosing the right material for our garden back in 2015 and I kept coming back to antique metal washtubs. They’re not cheap, I found them for up to £125 for the smallest and more for larger. They tend to be zinc coated and therefore water tight. When I found one for £25 in East Sussex I thought it was too good to be true – it was, there were leaks.
How to plug holes in micro pot ponds
I considered using Butyl liner in the whole tub but in the end used waterproof putty usually used by plumbers on pipes. It’s incredibly hard wearing and long lasting. I plugged our holes in 2015 and haven’t had to repair it yet.
Does micro pond water have to be rain water?
No, this is one of those big gardening myths born out of the fact it’s ideal to use rain water as it’s pure, but ultimately it doesn’t really matter. If you use tap water, it can be quite hard (i.e. contains lime) in some areas and will all have some chemicals to clean it for drinking. To deal with this, you just fill up the pond a day or two beforehand and leave for the chemicals to evaporate, making it cleaner for plants.
When I planted ours, it was in a rush for Big Dreams, Small Spaces so I didn’t have the luxury of waiting. I filled it with tap water, bunged the plants in and they were perfectly happy with no ill effect whatsoever.
Do you have to have a filter or pump in a micro pond?
No, this is another myth that’s exaggerated from a small fact. Wildlife ponds in general look after themselves. Pumps are for oxygenating and cycling water so it doesn’t sit still. If you have the right number of oxygenating plants it won’t need it. Equally, cycling water prevents midges and mosquitoes breeding in still water. I find by putting our pond in full sun in the open (the ideal location for a pond anyway) this has never been a problem as the sun and wind deal with them. A filter is if you want cleaner water – usually used when you have fish too – so you can add one but actually I find clean water detracts from a natural looking pond. Slightly mirkier water hides the baskets while still being transparent enough to be pleasant.
I’m not a fish expert so won’t go into them here – personally I wouldn’t recommend them in pot based micro ponds because they can get quite hot in mid summer sun. I’d imagine that would be unpleasant if not deadly for fish. Plus fish do make ponds mucky, which is a real hassle.
Plants for pot micro ponds
There are a whole host of plants available, you just need to be sure they are suitable for small spaces of water and therefore usually dwarf. Don’t overcrowd it, which is the temptation, instead leave enough space to enjoy the plants and the water itself. After all, the water is the key element. If you over stuff it with plants, while they’re different and interesting, you may as well grow normal pot plants. Seeing water is peaceful even on a small scale.
Firstly you need an oxygenating plant like Ceratophllyum demersum, which you just chuck in and it floats around. I find this plant can die off in winter so needs replacing, check on yours in spring.
Waterlilies are probably the most popular to have because they’re so different to other garden plants, ours is Nymphaea ‘Laydekeri Fulgens’ but there are quite a few in different colours, like Nymphaea candida which is white. Dwarf water lilies are placed at the bottom of the pond as they need the maximum depth to stretch their pads and flowers up from. Other than that, they are literally the easiest plants to grow.
Marginal plants, those that grow just below the surface of the water, usually at the edge of the pond. Their crowns sitting at or up to 5cm below the surface of the water. Marsh Marigold, Caltha palustris is the classic example, alongside Irises. Iris ‘Kermesina’ and ‘Gamecock’ are good.
Planting the micro pond plants
The only technical bit with ponds is that plants are grown in baskets not pots (buy online or from specialists) allowing roots and water to mix properly. You must use an aquatic compost, which can be hard to find in some garden centres but those with aquatic plants will have it. Or buy online.
For sizes of baskets to use, please do check for each plant. A dwarf waterlily and iris can be quite vigorous, mine grow in 20cm baskets. The Iris can quickly outgrow this and need dividing or potting on. Add gravel to the top of the compost to prevent lots of it floating up in the water.
Gradually lower the basket in to its position. Some compost will muddy the water but it will settle after a day or so. The marginals will need to rest on a brick or upturned pot to sit higher up. Make sure this object is sturdy enough to offer a solid platform. You can buy cages to prevent plants blowing about, but with wet compost and gravel I find this unnecessary personally. Our garden may be in Central London but it’s in a wind trap and very windy, no pond plant’s ever toppled.
Maintaining micro ponds
You shouldn’t have to clean a micro pond unless it gets chocca with leaves in Autumn. To prevent this, cover it with a net as leaves start to drop and then remove it when all leaves have fallen from trees. It doesn’t look fantastic but is for a short time only. Or, let them fall in and scoop out later. Whichever you mind least. I go for the latter these days as scooping out a tiny pond doesn’t take long.
Some algae may build up but not really and this is easily removed. Plants may need some specialist fertiliser capsules from aquatic plant nurseries, however I am finding this to be less necessary at the moment. I haven’t fed this year and my Iris seems stronger and the waterlily is flowering regularly as normal.
How wildlife friendly is a micro pond in a pot?
Our cat loves drinking from our little watering hole as do wood pigeons who comically waddle around balancing on the side. This year we have pond skaters – wherever they came from! We don’t have frogs (in the garden as we’re in them middle of the city) though I know with the right access they can easily get in and out of a micro pond and will use it. You’d need to build a little ramp or steps up on the outside and inside so they can get out too. We’ve also had the odd dragon fly.
How much wildlife you attract is really up to you in terms of the access you give them, just think about how they will access the water and get out if they fall or jump in. As I say, I’d avoid fish for mess, unless you want to attract Herons to eat them.
Micro ponds in pots are one of the easiest additions to a garden. Not only do they need no watering (bonus!) they add a sense of calm and gravity no matter how small.