Posted: 05/10/2014 at 09:43
I don't like covering soil with plastic/carpets or whatever - I think it makes it airless and stagnant and discourages bio-diversity needed for good fertility and soil structure.
I'd rough dig it now, removing all weed roots etc, and then leave it rough for the winter frosts to break down the clods.
In the meantime get some farmyard manure and stack and cover it in a corner of the plot, and then in February, or as soon afterwards that it's possible to walk on the soil without it all sticking to your boots, then spread the manure and turn it in. When it's time for spring sowing and planting that should have produced a good friable tilth that you can rake down into a seedbed.
Don't forget to leave an area without manure for growing your root crops (carrots, parsnips etc) as they will fork if grown on freshly manured land.
Good luck with your allotment adventure. Let us know how you get on