David Lewis. Photograph: David Yeo for the Guardian

David Lewis: I am a bit of an urban bunny. I like living in the city. When they built The Roof Gardens in the 30s, London was a smelly, horrible city you wanted to escape from, so they put an 8ft wall around it, with tiny views out. When Babylon, our restaurant, was built in 2001, it was all about the views, and celebrating this fantastic city.

The soil depth is 45cm at most, but it’s enough. We try to garden as if it’s a regular garden. The trees that everyone says you should plant on a roof garden, such as eucalyptus and silver birch, are really thirsty, and not particularly strong on their roots: the oaks and the lime trees in our woodland garden are far more stable – they’ve been here 75 years. The soil isn’t the best, but we only mulch; we don’t feed with chemicals.

Two trees were extravagances: a fig tree and a pomegranate, which came from Italy. I’ve been watching the figs ripen for weeks – you have to get here early before the birds get them. A few times a year I can breakfast on figs.

The garden wasn’t designed to have wildlife, apart from fish in the stream. We sometimes get birds’ nests inside the garden. We’ve got a flock of greenfinches that fly around, and our ducks nest in the woodland area. Our resident flamingos are very happy here: they wander off into their houses when there’s a rowdier party. There are lots of urban myths about things that have happened to the flamingos over the years.

It’s my dream job being head gardener here. It’s a special place, because everybody has their own memory of it. You get everything from “I partied here until 3am when it first opened”, through to “I came with my aunt for afternoon tea”. One man came to see our show garden at Chelsea, and he had postcards of the gardens from the 1940s. He was dying, and he’d come to return them to us.

My favourite spot

At the back of my shed we have our beehives. Checking on the bees’ welfare and collecting honey are great times. My mobile is off and there are no interruptions.

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