Pond building

Documenting failure is also important. Sadly, I was weak and gave up on a liner-free natural pond, but look how pretty! It will still host wildlife, and that was the goal.

A slow and ponderous process

‘Using small and slow solutions’ is a principle of permaculture for very good reasons. One of them is that you really get to know the details of how something works. The process teaches one patience but in this case it was almost too educational! After we chose the spot and dug the hole, immediately — like seconds later, all manner of insects came to investigate and occupy this new crevasse that had opened up in their world. The hole in the ground became an insect hotel.

Building our little wildlife pond went through many stages. We selected a natural low spot in the lawn for the pond. We figured rain was flowing towards it anyway. There was an old unused septic tank buried adjacent to the area which we did not want to dig out. Digging the hole also revealed that this spot was used in the past to bury waste. We uncovered many strange objects, a blue ceramic fish, a big rock painted with an inspirational message, lots of metal, and of course plastic sheets and the ubiquitous landscape fabric. (Nothing infuriates me more than landscape fabric.)

1. Location of pond in the garden 2. Area marked and first dig 3.Eva measures depth of the lowest point 4. Making the levels 5. Lining with bentonite clay 6. Sitting pretty 7. Filling the pond 8. Watching it drain away 9. Soggy bottom

My colleague Eva dropped by for a visit and helped out. My partner dug the initial hole and we shaped the layers.

I was intent on building a natural pond using no liner. Usually this is possible when you have clay soil to compact down or boggy land which water fowl like ducks and geese land on. Eventually their poop makes a water fast barrier and you have a pond rather than bog, local oxygenating plants start growing and prevent algae, keeping the water clear. When you think about it, ducks build their own ponds.

We don’t have clay, not even close, we have extremely stony, free draining, dry soil so I ordered some bags of bentonite clay powder which is supposed to create a water seal and played with that with the help of a good friend. The seal didn’t hold, we laid it too thin and then maybe too thick and worms burrowed through it, so the experimentation went on for about a year!

Diagram from a useful second-hand book. A lucky find.

Next we tried thick layers of grass using a method called gleying, creating anaerobic conditions that will result in water-logging. The grass creates an air and water tight layer as it rots into an anaerobic mass. Mixing the bentonite clay with grass seemed to be working on the bottom of the pond but not on the sides. It was also taking a very long time to get it right. My colleague Leonie in Berlin, who told me about this method, was also doing this with her team, but on a much larger scale.

We waited till the solitary bees nesting season was over, and months later we could resume sealing the pond hole with bentonite clay in layers. The water wouldn’t stay, leaking out slowly till only a soggy bottom remained. A big hole in our garden for almost two years, was not aesthetically pleasing to the other person who also lives with me here, so I finally gave in. My least favourite permaculture ethic ‘people care’ kicked in. We put in a durable liner in late summer, 2024.

My most inglorious pond moment.

We found a water plant shop not too far away and got an assortment of pond plants for different depths, including oxygenators, floaters, plants for the edges and even a perennial lotus. Moving from the Netherlands where a great many plants survive their mild winters to the south of Sweden which is supposed to have mild winters taught us that mild winters is a relative term.

I also discovered azolla, one of the floaters that reproduces extremely quickly and can fill a pond in days. It is also important to not let it escape to local waterways. However, the problem is a solution; you can eat it and it can be used as mulch! (See Morag Gamble’s Video)

Azolla multipying at a furious rate. Pics 1 and 2 show 25 days of azolla growth. I also brought it indoors for a flower arrangement.

Wildlife appeared, swimming beetles and insect larvae appeared. The awaited dragonfly came by to check it out a month later. We’re still waiting for frogs and ducks. Long and slow solutions!

The pond in winter froze solid; all the plants in there may be dead. But I’m hoping I’ll be surprised, the Siberian irises planted on the edges were showing sign of life yesterday!