Chris was told by the Botanical Gardens' moss expert that moss appreciates a diluted mixture of fresh cow dung and yoghurt to get established. Luckily the cows are back on Midsummer Common, so armed with a bucket and spade he sallies forth to collect some of the good stuff. It's a nice day, and there are lots of picnickers out, so they get to enjoy the rare sight of a cow dung hunt in full flight.

The cows are obliging, and Chris soon has all he needs. Viewers of a squeamish disposition may want to skip the recipe section.

It smells as good as it looks! Armed with a paintbrush and a strong stomach, Chris coats the fabric in the mixture...

...and then attaches the moss from the top down