The Soil

This garden in the German city of Hamburg grows on sandy soil that was once the base of a bog. Peat-cutters took away the "turf" to use as fuel a couple of centuries ago, and the area was later farmed. The topsoil layer is exceptionally thin, perhaps thinner now than five years ago as a result of our excavations and building work on the site. While we can fertilize to make up for the poverty of the soil, there is little we can do against its utter lack of water retentiveness. Here and there we have added the mineral bentonite, which gives the topsoil a more loamlike character, but mostly we must irrigate throughout the spring, seeing every dousing of rain and sprinkler work quickly trickle away into the sand below. The summers here tend to be wet, so the sprinkling effort in the hottest months is not so great. Wherever possible, plants that like dry conditions have been chosen for the garden.