Shoot for the moon: Can planting by the lunar calendar help a garden grow? Emma Townshend sees moon-power in action in Sussex

Oh, how times change, honestly. The other day I was trying to do some Christmas shopping in Selfridges and I realised that even in that temple of consumerism you can now buy biodynamic. Dr Haushka products are available on the beauty floor, with all their extraordinary scents and strict biodynamic planting principles; and then I spotted, from my position in the nearby Muji concession, that London's most glamorous store is now stocking copies of Gardening and Planting by the Moon 2007, by Nick Kollerstrom.

Biodynamic cultivation is often summed up lazily as 'growing by the light of the moon', and yes, the cycles of moon and stars in the sky are used as important indicators for planting and cropping, with certain days regarded as auspicious, depending on whether you are growing root or fruit crops. A quick glance at either Kollerstrom's book, or the official biodynamic sowing calendar - written by the austerely German Maria Thun - does reveal a profusion of astrological symbols. But reducing it all to moonshine alone is to simplify it too far, there's definitely more to it than that. I went to the village of Forest Row in Sussex to meet the farmers of Old Plaw Hatch, where the lunar sowing calendar is a much consulted document, to discover just what it is about biodynamic ideas that makes growers get so excited.

'It's about a community and a cycle,' says Tom Ventham, tiredly. He has just spent a good 20 minutes talking enthusiastically about his cows, so it's not the work that's exhausting him. I think it's trying to explain biodynamic ideas to an uninformed outsider that he finds slightly dispiriting. 'I know some other farmers think it's all nonsense. But if we go to a meeting, you look around, and I swear you can tell the organic farmers, because they're smiling!'

Biodynamic growers, who identify their carefully tended produce with the 'Demeter' symbol, are inspired by Rudolph Steiner. Steiner was a 19th-century thinker who had both odd and visionary ideas, and it's the visionary ones that continue to inspire the Demeter clan. What's powering Ventham forward is his whole-hearted belief that he's doing the right thing, for the community who live and work on the farm - some 25 souls - as well as for the animals, and for the customers, who buy 90 per cent of the farm's produce direct from the delicious shop (signed off the road between Sharpthorne and Forest Row, West Sussex).

'The farm is for the community. We are owned by a trust, and making money is not our highest goal. Building a relationship with the community here, supplying a community, is what we're here for. Steiner said an economist can't be a farmer, and a farmer can't be an economist.' For Tom Ventham, farming biodynamic means trying to bring a different perspective to work, where the health and vitality of the farm as a living entity comes high up the list.

As the son of a conventional dairy farmer himself, he knows the perils of the intensively farmed life. He has chosen to commit himself to this different way of doing things, yet all the signs point to it having been the right choice - his chickens are the blackest, glossiest birds I've seen in a long time, his pigs are fiercely alert and inquisitive. And the leeks and other winter greens growing in the fields are strong and beautiful, (especially once you've brushed off the few miniature slugs that show how unchemical the system is here).

So what lessons are there for the garden grower of vegetables? We are probably not going to be able to use the horns of our own cows to make some of the more arcane preparations advised by the biodynamic farming association. But on the other hand, lunar farming methods have been used by cultures for thousands of years. And many allotment growers swear by them too.

At Plaw Hatch, what's being added is the idea of the generosity of farming - the love and the hard work put into a crop - the ability of the farmer to be thanked directly for his or her work, and the fact that the customer can go away knowing exactly which soil, which field, their leeks came from, and who grew them. It sort of blows away the supermarket practice of naming the grower on the plastic box.

You don't have to take on board every single one of these ideas to find some of it valuable. What's inspiring is the notion of adding something beyond the financial bottom line. It reminds me of the American writer Lewis Hyde's theory that creative work is always, in some senses, a gift. When someone does something for you with love and commitment, even if you pay for it, something beyond price is given at the same time. For anyone who grows their own food, that is surely the most precious idea.

Nick Kollerstrom's 'Gardening and Planting by the Moon, 2007', is available from Quantum, £8.99. Maria Thun's Biodynamic Sowing Calendar, £7, from www.biodynamic.org.uk; The Lunar Calendar, £5.45, from www.riverocean.org.uk

If you do one thing... celebrate the solstice

While we've been moaning about the nights getting ever longer, our plants have been feeling the shortage of light in every cell. So there are plenty of reasons to rejoice on the shortest day of the year, 21 December, after which days will slowly get longer again. Make sure you get outside on Thursday and enjoy the sight of little green bulb shoots, just springing up.