Our little greenhouse looks very romantic this morning, half-covered in big yellow walnut leaves. I’ll go and dig it out in a minute.

It’s been in place for three weeks now and I still keep going outside (or at least looking out of the window) to admire it. Nothing could look more at home in this Victorian garden of a Victorian house than this prim, spiky little construction, pale grey, with its finials and spiny ridge. I managed to preserve the old box hedge round the bed it occupies, so it looks totally bedded in. The main axial garden path passes it, then climbs five steps to a half-concealed terrace. At a glance you might think another whole garden lies just beyond it….

Alitex have done a good job. It’s only when you open the door that you realise it is aluminium, not timber, but it still feels solid, and the door shuts with a good deep thunk. Benches take up the path side and the end, leaving the grey brick wall free for, at present, standard purple-flowered solanum rantonnei and fuchsia boliviana in pots.

The end bench will be partly occupied by a potting “shoe” (I didn’t know they were called that) when I can find or make one the right size.

The benches are covered (or rather filled) with Hydroleca: little balls of heat-expanded clay. In the past I have used sand, but the makers claim magical properties for this product. It will apparently store and release moisture precisely as needed, is lightweight and hygienic …. . the balls are rather big, though, for some of my tiny pots, at present mainly of bulbs, so they topple over. I’ll get used to it. The long side wall opens as one light operated by a splendidly retro lever. The top light opposite opens automatically at a given temperature. Under the end bench is a reservoir, filled from the gutters, with a hand pump: I’m not sure how to prevent the water from going stagnant and smelling, but I’m sure there’s a product for this, too.

At this time of year the merest spot of colour shines like a light. There is a red light shining at me now; Salvia van Houttei; only one. A moral tussle: do I go over the road to Rassells Nursery and fill my benches with ready-made colour? Just now it would be cyclamen (pretty shrill colours), primulas (ditto) or pansies. Or do I treasure the little I have – until the bulbs come out?

There is endless sustenance and comfort to be found in old gardening magazines. Sustenance, because the ideas and answers flow seamlessly down the generations. Comfort, for the same reason. My resource on a gloomy November afternoon for many years has been The Gardeners’ Magazine, conducted from1826 to 1848 by the apparently unwearyingly J. C. Loudon in the intervals in writing his majestic encyclopedias.

I picked up the volume for 1838 this afternoon. 175 years ago gardeners’ concerns were very similar to ours, but their candour and freedom of expression very different. In the September issue is an illustrated (with engravings) article on the Duke of Bedford’s garden, just up the road from here on Camden Hill. One year into Queen Victoria’s reign it is already the epitome of Victoriana: a restless mass of geometrical planting in the brightest colours, intensely gardenesque (to use Loudon’s coinage) except for an orchard of fifty trees on the south slope. Every plant is enumerated in the engravings and its name and colour listed. It is in every sense a dazzling list.

In November, though, comes the critique, something no modern magazine would ever publish. Poor duke, and poor Mr Craie, his gardener. Mr Glendinning of Bicton, having avowed that his “few observations are by means intended to detract from the praise that is so justly his due” lambasts both the design and the cultivation. “The shrub with the spherical lumpy head’ he writes, ‘.. appears like an enormous hedgehog’ The beds are too close together, the paths are wrongly designed, and he “strongly objects” to placing pots with plants in them on walls. He “cannot see what business they have there”.

In the same spirit of candour the conductor reviews front gardens, or “street gardens” as he calls them. He strolls through Brighton commenting on the residents’ efforts. No. 15 Marlborough Place gets the thumbs up for “no more than two square yards” containing “dark and light-flowered nasturtiums, convolvulus major and mignonettes”. Nos. 16 and 17 York Place seem to win his gold medal for their “very select planting” in which Lobelia gracilis, Anagallis coccinea grandiflora and verbenas “make a conspicuous appearance”. “The pyramids of heartseases were remarkably fine”. Loudon even tasted one gardener’s potatoes and thoroughly approved of their “flavour and mealiness “. If a front garden was not up to scratch Loudon was not unkind; he moved on, but a ducal garden was apparently fair game. Today? The rule seems to be De hortuis nil nisi bonum.

Mr Craie, that same duke’s gardener, had some ingenious tricks. Does this one make sense? To preserve a tender rose bush, in this case R. Lamarque, he budded a hardy rose near the tips of its branches. The yellow Lamarque survived the dreadful winter of 1837/38 thanks to R. Brennus, a crimson rose, being budded on the year before. “Brennus flowered first, luxuriantly, and was followed by Lamarque, which also flowered well, though the latter, in all cases where the shoots were not budded, was killed back by the frost. It thus appears that the vigorous growth of the scion had thrown the Lamarque stock into a state of vigorous growth at a time when the Lamarque would otherwise have been quite dormant. ” Does this make sense? Was it hardier because it was in growth? Does anyone do this today? I plunge back into my dusty old leather volume eager for more horticultural history.

To Kew to se what autumn fruit and colour has been spared by two weeks of cold and windy weather. Grey is the colour of the season – indoors as well as out, it seems. We see it in furnishings, in fashionable décor (Nina Campbell’s new book Interiors is full of grey, and so is our son’s new house.) Is grey the new cream?

And yesterday it was the theme in Kew Gardens, remaining leaves now only scattered patches of warmth. But what warmth! How is it that the yellows ands reds of autumn generate their own wattage? It feels (perhaps it is) lighter under a yellow sweet chestnut or an orange beech than under the open sky.. These were the trees providing the warmest patches; most of the maples were bare. I had to cross a lawn near the Palm House to identify a small tree that formed a neat tower of deep scarlet: Malus trilobata from the Eastern Med. One to note.

But the gardens were full of activity – and electricity. They were preparing for the Christmas illuminated trail, a mile of paths lit with every modern lighting trick; the first time Kew has opened at night in winter. (The show runs on certain days between November 28 and January 4; see the website). I remember when Westonbirt first did the same thing; it was an inspiring sight; trees make ideal subjects for theatrical lighting.

And hortiphones,,too: strange His Master’s Voice-style speakers scattered around ready to perform: music? Commentary? Mysterious vegetable sounds? I can’t wait.

Home from a wintry dash to Krakow and Beaune, two of Europe’s best-preserved ancient towns. Beaune still has its girdle of walls; at Krakow they pulled them down and replaced them with a green belt charmingly called the Planty (can it really mean just that?), now a circular park of mature oaks and limes and planes. Every town should have one.

Home to find the new greenhouse ready for commissioning. Gulp. The plants that go in here depend entirely on me for their survival. The bench is a blank sheet, a bare wall, a challenge. Happily the last panes of glass have gone in just as the temperature falls to zero; the first inhabitants are genuine refugees; a cymbidium, some favourite pelargoniums from Saling Hall, some salvias still in bloom.

The lemon pot is too heavy for me to move from the verandah; shall I be able to keep it snug enough tucked up in fleece, with a glass roof but no walls? Not I fear if this winter is like the last.

But a score of pots of bulbs – also refugees, this time from the squirrels that have already been munching – gives the bench a look of purpose and hope. Snowdrops are poking up; I shall see them this winter in a completely different focus from the white rugs of the countryside. Iris reticulata is stirring. Worryingly a cyclamen the size of a Chelsea bun is not.

How carelessly, casually, unthinkingly did I once chuck armfuls, wheelbarrow loads, whole branches on the bonfire. How slowly, thoughtfully, with what infinite pains did I spend this afternoon dissecting, dividing, dismembering my prunings with my secateurs to cram them into the council’s black plastic bags.

It is the difference between the country garden and the urban one. There are no big gestures in a garden shorter than a cricket pitch and no wider than a front parlour. Nor in a garden whose only outlet is the exiguous all-purpose corridor between the back stairs and the front door.

There are compensations, though. Town gardening, I’ve decided, is like putting on reading glasses. The foreground is enlarged, the distance blurred. But the object of your attention appears in such clarity of detail that it can occupy your mind like a whole landscape. Is this what William Blake meant when he saw ‘a world in a grain of sand’?

Today’s job was reducing a climbing hydrangea that was blocking the eastern light from the new verandah, the library and the kitchen. They are powerful climbers, equipped for tall trees and long branches, their brown wood stout and flexible, their foliage dense and their flower heads many, copious and intricate. Structurally they are composed of multiple right angles or near right angles, each ready to snag a plastic film. The only way to fill a bag with them is to chop them into little bits. By the end of three bags I know their anatomy intimately. Hydrangea petiolaris is more than a mere acquaintance now.

I look round the garden, the falling leaves, the growing climbers, the old growth to be cleared away – not to mention the tree to be pollarded – and see a future of black plastic bags stretching away to the distance like crows on a telephone wire.

I can think of a dozen reasons for visiting New York in October – the best month in this continent of extreme weather – but the one that comes uppermost in my mind is the Conservatory Garden in Central Park

I know I bang on about Central Park, probably once a year, but then it has qualities none of our London parks (I love them too) can match. Seemingly endless paths (trails sounds more American) among huge grey rocks like monster whales and enormous trees, across savannah, skirting lakes and ponds, leading to cafes, kiosks, the boathouse restaurant, the zoo, the auditorium…. and several gardens. The Conservatory Garden, the most accomplished, the most formal and the most complete in itself, is way up around 105th Street, almost in Harlem.

Its centre is an ‘Italian’ design – though it would be hard to find avenues of crab apples around a simple level lawn in Italy. The ‘English’ third is the most intimate, cloistered among yew hedges, sheltering a bronze of Mary and Dickon of The Secret Garden, reflected in a little waterlily pond.

The ‘French’ garden is the October event: an overwhelming display of Korean chrysanthemums, a bank fifteen feet wide right round a rectangular piazza, enclosing the city’s jolliest fountain; three mischievous and nubile young ladies dancing round the water.

The chrysanths were a gift to the city in 1947 as a war memorial. The donor was Mary Lasker from Chicago, a huge benefactor of medical research. They were originally grown from seed, a strain developed by the Park for decades, selecting a wonderful palette of brilliant colours, orange and violet, yellow and white, red and brown. Other gardens show them oriental-style, extravagantly coiffed into pompoms and cascades. Here they are grown as they would grow in some dream meadow, a random medley, not pinched and primped but tilting this way and that, jostling, playing like the dancers round the fountain.

These days I’m told they are grown from cuttings and planted out from 2,000 pots in late May. Not that they are tender, even in New York winters, but they replace the spring bedding of 20,000 tulips. They draw New Yorkers like a baseball game. I’d love to see a really full-throttle Mum Show in England.

The sun is low enough in the sky this afternoon to rub in just how little light our new garden will get in winter. There will be improvements: the overhead shade of the huge sycamore and big walnut is going to be massively reduced. But this is looking forward several seasons. Half the garden will see no direct sunlight all winter.

I am turning over various possibilities in my mind. Portugal laurel, ivy, aucubas and some snazzy box topiary were our predecessors’ solutions. But I crave a smooth restful green patch; the equivalent of a lawn, which would never thrive here. Is a moss lawn a practical possibility, I wonder? I dream of the green tranquillity of the moss gardens of Japan. But does it need the warm wet climate of Kyoto?

Look up ‘moss lawn’ on the internet and every reference is about getting rid of moss as a nuisance. The only pro-moss site I can find is Gardens Inspired, from somewhere unspecified in the (I suspect southern ) States. Debra Anchors gives recipes for planting a moss lawn: literally recipes; they involve scraps of moss collected from nearby put in a blender with either yoghurt or beer, then sprayed on to bare ground and watered until it goes green. I love the idea. Worth an experiment, surely? I’ve heard it said, too, that regular spraying with Round-up can encourage it .

Alternatively, if I do nothing, our current modest crop of mind-your-own-business, the pretty little Helxine (or Soleirolia) soleirolii, will pretty soon do the business for us. Its tiny bright green leaves are the terrestrial equivalent of duckweed. They say it is almost equally pernicious, delicious though it looks in the interstices of old greenhouses.

Now that the squirrels have almost finished chewing the walnuts on our neighbour’s tree and dropping the remains on our garden they are starting on our pots of bulbs. I have been planting pots in anticipation of the greenhouse we are excitedly expecting in a week or two, using what is left of our collection of wonky old handmade ones. (I scan old garden sheds, greenhouses and shops selling bric a brac wherever I go, hoping to find these increasingly rare veterans).

Narcissus seem to be the squirrels’ first choice, with Iris reticulata also popular and snowdrops an acceptable snack. Do tulip bulbs have less scent, or is it because I plant them deeper that they have (so far) been relatively unscathed?

The brick base of the greenhouse is all ready, a (very) minor masterpiece in reclaimed London stock bricks in their characteristic medley of gentle colours: yellow, pink and grey. It is already hard to distinguish from the surrounding garden walls. The bricklayer who built it is from Croatia; a gentle smiling man with not much English. When I told him how I intended to fill it with flowers he said “I like this job. I like flowers very much. At home I have flowers everywhere; in the hall, in the kitchen, on the walls. People say I am like woman’.