A few months ago we got an allotment, it was extremely overgrown and the soil is full of weeds. We've since cleared the plot and laid a plastic weed membrane on top and are now gradually putting in some raised beds. There has been some manure left by a local farmer which we have laid on top, but have then re-covered with the plastic weed membrane.
My question is, is this correct? Do we need to cover it, or should we leave it uncovered for the frost to get to? I'm worried that if we leave it uncovered all those weeds we have managed to kill will grow back.