Go for it, just remove any potato / tomato plants and rhubarb if you can find any. Don't worry about the plot not having grass, it's not a necessity and would be gone in no time anyway.

If you'd like to top up the piggies' greens, just cut some of the stinging nettles (which seem to do so well around our allotments

) and other 'green bits' you can pull from the hedgerows.
