A VISIT to Down House in Kent, the home of Charles Darwin, proved fortuitous.

Darwin spent a great deal of time in his garden carrying out experiments and thinking (there is a dedicated thinking walk).

One of Darwin’s experiments was to measure soil displacement caused by worms, and his son Horace laid an experimental “wormstone” in the lawn which you can still see today.

Fascinating in itself, but Darwin also wrote, in 1881, a book based on his worm experiments entitled The Formation of Vegetable Mould Through the Action of Worms, which proved to be a best-seller and sold faster than his more famed Origin of Species had.

I managed to get hold of a copy of this book which is now only published on demand (I fear there is little of that) in which he champions worms as “playing so important a part in the history of the world” with their earth-ploughing capabilities.

“Worms prepare the ground in an excellent manner for the growth of fibrous-rooted plants and for seedlings of all kinds,”

he wrote, continuing with something rather timely: “Worms drag an infinite number of dead leaves and other parts of plants into their burrows, partly for the sake of plugging them up and partly as food.”

Their secretions, mixed with earth, form the “dark coloured, rich humus, which almost everywhere covers the surface of the land.”

I thought this rather relevant for a “down to earth” column, and a pertinent reminder that a healthy soil is the basis for growing healthy plants, and that worms, as well as fungi, bacteria and other microscopic creatures, help to create soil structure and fertility.

And with the first frost warning of the autumn forecast this week, nature will be providing one of the materials for free compost to keep that soil healthy - leaves.

The easiest way of making leaf mould is to gather leaves in black plastic sacks, tie at the neck and put in a corner of the garden for at least a year.