Functioning

If you only need a small growing area, it can be very rewarding to make a raised bed.

1. On average, the fertile root zone of natural soil is only about 20 cm. Under this, the organic matter content, also known "humus", reduces quite dramatically. With raising the bed and adding more organic matter, fertility is improved enormously. Also, drainage issues are solved, although sometimes the bed may drain too much, resulting in extra watering needs.
2. The beds can be made so high that for most (superficially rooting) vegetables, the quality of the underground becomes irrelevant, making it even possible to make a garden on an asphalt surface or on the polluted ground.
3. Raised beds are conveniently high for gardeners, as they save stress to your back!

They are also convenient for keeping out certain unwanted weeds and insects. The disadvantage, however, is that they are rather costly and time-consuming to construct. Most raised beds are made of nice timber, which doesn’t last long, a pity! We, therefore, choose to use old pavement slabs.

Materials and construction

In our case, we transformed an old football field with sandy soil into our wheel garden. We made a pattern of the garden (half a wheel) and cut out the paths to a depth of 10 cm, turning the soil cakes upside down onto the future beds. We inserted the slabs 10 cm deep into the ground at the edges of the paths. The paths were covered up with cardboard to prevent weeds, followed by lots of wood chips. Each bed was then covered with a few wheelbarrows of (oak) leaves, manure and plastic sheets with little aeration holes, so the old vegetation could start to decompose. In the late spring, we removed the plastic and the leftover organic matter, and the beds were entirely clean and warm for seeding!

Maintenance

The only maintenance required is to keep on adding wood chips to the paths, so weeds are suppressed and counterpressure is given to the stone slabs so they don’t slowly move outwards.