A technique for mounding potatoes in a mandala bed without importing soil, with the benefit of improving fertility and increasing organic matter.
by Grahame Eddy
I like to mound my potatoes by pushing soil up against the sides of the growing plants eventually creating quite a big mound. The theory is that I can get a greater harvest from the same space. But when I started using the Linda Woodrow style mandala beds I was struck by the difficulty of bringing in more soil to the bed as it would tend to spread outwards, and also would smother more than just the potato plants.
So, I came up with the idea of mounding from a small section of the bed and eventually building a compost heap in the resultant hole.
The photo above shows how the potatoes are growing in an arch directly out from where one of the fruit trees grows. Initially the seed potatoes are placed in a ditch, to start off with some initial vertical space. This image is looking down over the bed from above the tree.
When the potatoes reach about this height I then start to dig the soil out from inside the curve and mound it up against both sides of the potato plants just leaving the tops protruding. It is surprising how quickly the plants take off from here.
In this next photo, above, you can see the initial mounding and the beginnings of a hole. Over the next few weeks I will continue to deepen the hole and mound the soil up around the spuds. Once the hole is deep enough I then build a new compost pile in the hole — see the next photo (from a previous year).
Once the potatoes and the bed in general reaches maturity, the compost has rotted down. I then spread the soil back over what remains of the compost heap, or better still, let the chickens do it on their next rotation.
With this system the compost also feeds the roots of the fruit tree by creating a compost heap where it would not normally be built in the woodrow system. I can often build these small (but still well sized) compost piles using weeds and materials found close to the bed.
The quality of the soil in these parts of the beds is remarkably good after the first use of this technique.