For all the years I've lived in London, there are still corners that I've never explored, only to be put to shame by how much visitors like Darlene can cram into a week. But yesterday I finally did make it to Chelsea Physic Garden which turned out to be even more enchanting than I expected, a secret walled garden hidden away from all the traffic on the Embankment. It's been on my one-day-I-must list for years. (No excuses in future now I find that the bus stops right outside the gate!)

Chelsea was looking so pretty in the sunshine yesterday, roses tumbling over garden walls, yellow irises and bright red poppies as if an artist had tipped a pot of paint over the flowerbeds ...  and I never expected to see grapefruit growing on a tree in London. (A gardener told me that the fruits don't fully ripen, so they use the windfalls as slug traps.)

I had a lovely lunch of salmon en croûte in the sunshine, with jars of pink peonies on the table, then strolled down the road to make another tick on my list ... yes, I finally got to visit Carlyle's House and now I really must get round to reading The Carlyles at Home.

What a little gem. The painting above is the endpaper of the Persephone edition and still hangs in the Carlyles' sitting room, which still looks exactly the same as when, in 1857, the artist promised a picture that would be 'amazingly interesting to posterity a hundred years hence.' The rent was £35 a year; imagine how shocked thrifty Jane Carlyle would be if she knew that today that would barely cover lunch out for two.

Can you see the door right at the back? That opens into the china closet where in 1865 a housemaid called Mary managed silently to give birth to an illegitimate child while Carlyle had tea in the dining room with a visitor. At 2am the baby was smuggled out of the house wrapped in a table napkin.

Darlene visited on her last but one trip and this is what she thought.

And Virginia Woolf visited with her father in 1897 when she was 14. 'Take the Carlyles, for instance,' she wrote. 'One hour spent in Cheyne Row will tell us more about them than you can learn from all their biographies.'

VW was right. The house is so tiny that Thomas and Jane Carlyle seem so vividly alive here. You can see how the lives of middle-class women were so entangled with their servants when they lived so much on top of each other ... and how poor Jane must have struggled trying to run a house with a series of slapdash housemaids and a pernickety husband. And you completely understand Carlyle getting irritable about all the noise when he's trying to write his epic volumes of history... all that clattering from the kitchen, horses and wagons and tradesmen outside in the street, street musicians that had to be paid to go away, noises from the busy river, and all the jollity coming from those pleasure gardens down the road. It must have been like living on top of a theme park.

Needless to say, that Persephone book has been pulled out of the teetering book pile and dusted. Now that I've seen the kitchen and the china closet and Jane's secondhand sofa ... the book is going to feel like a visit to old friends.