As described in an earlier post , my garden has very thin soil (with rubble underneath) together with a large expanse of concrete in the form of an unused driveway. This meant that if I was going to grow anything well , particularly small trees and shrubs, then I needed to add quite a few raised beds to the garden. I’d already bought in 2 tonnes of compost/soil mix to fill my raised beds but soon realised that even that amount wasn’t going to be enough for the extra beds I needed.
Whilst having a mooch around my local (and very excellent) garden centre (Hulme Community Garden Centre) , I asked them what they used to fill their raised beds and the very helpful worker told me about “Hügelkultur” . I’d never heard of this term before but apparently it’s a German word meaning “mound culture” and which is believed to go back to the very old European practice of using fallen and rotten trees to grow crops by mounding soil on top of dead wood . The idea (now adopted by many permaculutre practitioners) is that it mimics what happens naturally on the forest floor , with the dead wood acting like a sponge, releasing moisture to the plants when the soil is dry as well as providing nitrogen and nutrients to the plants as the wood breaks down and decays. The garden centre had adapted this method to their raised beds by half filling the beds with branches, logs, leaves, paper , grass cuttings and other organic matter and then filling up to the top with compost and/or soil.
Not only had they cut in half the amount of soil they would have needed if they’d filled their raised beds using only soil, the plants growing in them appeared really lush and healthy. Sold! I was going to make my own Hügelkultur raised beds at home.
As my raised beds were already assembled I just needed to source a lot of dead and rotten wood to half -fill their empty frames. A friend of mine told me about a park where the council dumped tree trunks which were then cut up and put through a chipping machine. Although we managed to get a lot of old logs, both rotten and relatively fresh, I discovered that my empty raised beds were very “hungry” and so needed to get some more wood from somewhere else.
Fortunately, my council had been pruning a lot of big crack willow trees near my house and had thoughtfully left the discarded branches on the verge.
Once I dragged the big branches back to my garden , the hard work of cutting them up, and then laying them at the bottom of the raised beds ,was made SO much harder by virtue of the mini-heatwave we were experiencing at that time!
Once I’d established a base of branches and logs in the beds, I layered in a mixture of torn up cardboard boxes, grass cuttings, shredded paper and kitchen waste from my composting caddy. This was then topped with more rotten wood and finally finished off with a layer of soil/compost mix
I thoroughly watered my new Hügelkultur beds and started planting some of them up. Below is a rooted cutting I’d taken from an ornamental elderberry shrub which I’d “sourced” locally and which I gave a home to in one of the new raised beds. Those with a keen eye will notice that there is also a log which I’ve left partially exposed. Its from an old cherry tree and has been deliberately left like that in the hope that I might (and its a big might) get the delicious “chicken of the woods” fungi growing on it at some point as the log decays
With the remaining left over soil , dead wood, shredded paper, cardboard and kitchen waste, I decided to create several experimental Hügelkultur “beds” in 90 litre galvanised metal dustbins. One was planted up with Thimbleberry and another planted up with a hardy grapevine . The advantage of having them in these big dustbins is that it allows me to move them (admittedly with some considerable effort!) to other parts of the garden, if needed , whilst the rest of the garden develops and grows
Of course, the main emphasis of the garden is to provide a wildlife friendly space. The Hügelkultur beds provide an excellent habitat in several different ways. The decomposing wood will provide food , shelter and breeding sites for a whole range of different creatures, from beetles to woodlice to worms and to fungi – and all of which help to provide food for bigger creatures (such as birds and hedgehogs), further up the food chain. When I created the Hügelkultur beds, I also ensured there were a few gaps, at the ground level, to allow access for any visiting frogs, toads and newts which can use its moist “nooks and crannies” as a refuge in the summer and a safe hibernation site in the winter. The raised bed in the photo below was located in a shadier part of the garden and so I decided to plant shade tolerant shrubs such as gooseberries and black currants , along with a mass under-planting of wild garlic bulbs and wild strawberries . As you can see, the wild strawberries are already starting to spread and will eventually provide ground cover and a source of food for visiting birds