Crikey - I thought the whole idea of an allotment was to grow better quality veg for less money. I have been organic on my plot, but if you have rampant couch grass or anything alse as determined then old carpet does the job. If you want to be really padantic on the carpet question surely black polythethene is a damn site worse for the environment when you include the manufacturing process. Surely recycling is better than another trip to the tip?