If sills and ledges are few and far between, you can still become an urban gardener – you’re just going to have to get creative. Search for Tillandsia (air plants) and you’ll discover a cult of urban growers who find inspired ways to work with this South American perennial, whose short, wiry roots require no soil. Hang it from a fishing line around the door frame, wrap around a log propped up in the corner of a balcony, or suspend from a bird cage, terrarium or bell jar for a truly modern take on hanging basket. If horizontal space is non-existent, air plants can also be used to create so-called moss walls, whose popularity has increased in correlation with the shrinking of London’s gardens. If you’re flush, specialist contractors can turn your wall into something akin to a vertical lawn, but there are DYI kits if you really fancy a challenge.