The black woven groundcloth mentioned by Uli is also available in the USA from nursery supply companies. I use it a lot under raised beds and in other places where I want to exclude moles, which seem unable, or at least unwilling, to break through it. It will kill off some weeds. but you can't eradicate such problems as blackberries or bracken that way -- their roots are too persistent and will resprout after even three years. This groundcloth, which has a lifespan of about ten years even when exposed to sunlight, comes in various widths and is easily cut with scissors. However, if any debris lands on it in which weed and grass seeds can germinate, they will send their roots down through the groundcloth into the soil below. Jane McGary Portland, Oregon, USA On 6/1/2015 2:56 PM, Johannes Ulrich Urban wrote: > \We have our weeds, though. What I do when I really want to clear a > piece of land is covering it with a solid fabric made of woven narrow > plastic strips. It is used in professional nurseries to cover the > ground under pots or containers to keep everything weed free. It does > exclude light from the ground but lets air and water through. As it is > black the soil under this cover becomes quite warm. I mow the land > first as low as possible and then lay the fabric and fix it either > with pegs or with stones or heavy boards. it needs a season to kill > almost everything, the possible survivors can be easily removed. No > chemicals, no effort except preparing by mowing and laying the fabric. > But it needs time. The fabric can be used many times. It can be walked > upon and is sold on large rolls in different width.