Translation:Turf is bought in the local supermarket.
The dictionary says that 'turf' can be used as a count noun ('each turf was cut and stacked' – http://www.oxforddictionaries.com/definition/english/turf), so presumably you could buy turfs or turves, but turf itself is not a plural. And in any case, we generally use the word as a mass noun and simply buy turf.
The plural 'turves' would be used if you were buying strips of turf from a garden centre to cover your lawn. But it is a different meaning of turf.