This image shows the different layers that make up a Hugelkultur bed. It also shows how different methods of watering (drip or swale) penetrate the mound. I believe I’m right in saying the concept was put forth by Sepp Holzer from Austria.
I love the look of these and think I’ll have a go at one on the allotment at some point in time. It’ll be interesting to see how well the logs act as a sponge to aid with water retention. I’m also interested to see how the heat produced by the rotting wood and also the added heat captured from the sun due to the angle of the bank would affect plant growth. Be fascinatin to do a side by side with more traditional beds, see what I can do.