THE MOON gets no mention in The RHS Dictionary of Gardening. Nor do lunar phases. Unless I have missed some other reference, the masterwork of horticultural convention skips the whole subject. Gardening manuals of our ancestors though, were quite punctilious about it. Whether you look it up in Pliny or Thomas Tusser, every garden operation allegedly goes better with the moon in the appropriate phase.

The broadest application of the logic of lunar influence could be simply called tidal. Garden (or farm) operations that relate to growth are best done with the moon waxing towards the full orb, Planting-out and grafting are, quite reasonably, said to benefit from the flow of sap rising. If seeds germinate with a waxing moon it is nor absurd to suppose that their initial growth will benefit.

The waning moon, by this argument, is the time for jobs that call for a reduced flow of sap - of which pruning is the most obvious. And l have asked joiners whose work demands perfect timber: they seem unanimous in believing that trees should be felled between the full, and new moon, when 'the sap is down'.

These ideas (and there are plenty more, including many flat contradictions) have more currency today than when the RHS dictionary was compiled. The bio-dynamic movement is also waxing, and minds that are open to the quieter murmurings of the universe are not likely to ignore something so obviously potent, and so easily charted, as the moon that moves the oceans.

The problem lies in the interpretation. The book l have here, and that inspires these thoughts, is admirably candid about the manifest muddle of folklore.  It is a gardener's calendar for 1999 called Planting by the Moon. The introductory half of the book is a bizarre' mixture of astrology and horticultural common sense. The second half sets out in diary form the astrological year and its possible implications for gardeners - right down to mornings on which it is best to do nothing at all.

At moments it reminds me of Psychic Smith, the loony astrologer on The Sunday Telegraph. (Sample: 'Gemini: Consternation on Tuesday, when flicking through the Oxford Companion to Politics you find an entry on yourself. Lucky video rental: Here Come the Teletubbies.')

But seriously; I am going to keep an eye on the calendar's prognostications, and hope to report back that the cabbages were splendid.

Review form The Garden (Journal of the Royal Horticultural Society), January 1999