Saturday, 1 December 2012

Composting Part 2 - Worms

Composting Part 2

When I was nine or ten, my mate Dave, from five doors down, had a pet grass snake called Harris. We’d heard about snake charmers in India and decided to have a go ourselves. In the absence of a cobra or Indian flute, it didn’t seem a far stretch of the imagination to substitute Harris for the snake and a recorder, ‘borrowed’ from school, for the flute. Harris did’nt rise and sway in his glass-fronted tank but he did actually raise his head a bit when the music started. We thought this was due to the hypnotic beauty of Dave’s rendition of ‘Pub With No Beer’ but, in retrospect, was more likely a result of the pain rendered on his musical appreciation. Snakes ‘hear’ by detecting vibrations and these particular vibrations didn’t exactly gel with the ones the Beach Boys sang about.

Anyway, this was when I got interested in worms. I couldn’t afford a snake and thought a big worm would be just as good. It wasn’t, but at other things it excelled:

Charles Darwin, in one of his books, stated ‘It may be doubted whether there are any other animals which have played such an important part on the history of the world as these lowly organised creatures’. My first thought was of dinosaurs, but he was referring to earthworms.
Young worm pointing at developing clitellum with his tail

Worms burrow, taking  soil in at the mouth end. They then pass it through the gut, which extracts a bit of nutrient for breakfast, and excrete the remains higher up in the ground. Hence, worm casts. Darwin reckoned they lift 10tons of soil per annum in an acre of average English meadow, and the outcome is important to plant growth: burrowing creates tunnels which enable soil drainage and aeration. Soil they deposit higher up contains plant butties in the form of minerals which have been washed beyond the reach of roots, so that they are once again available.  The fact that worms then line the tunnels with dead leaves further illustrates their importance as part of nature’s recycling system, returning to the earth what came from it.

Of the 25 different species of earthworm in Britain, it is the tiger worm, or brandling, which we use in wormeries. This is the one commonly found under damp cardboard left out for the binmen. It works on the surface and is one of the most important compost makers.

Worms are hermaphrodite, which means they have both male and female sexual apparatus, implying that they could fertilize themselves. However, it is understandably more fun to do it with another worm, so you will find them lying together and exchanging sperm which is stored in special body sacs near the head. If you witness this, creep close and listen carefully. With a bit of luck you’ll hear them whispering  things like ‘ooooh, do it again!’. Each worm will then go away and lay eggs into a ring around its body called the clitellum. When ready, it’ll wriggle backwards out of the ring so that the sperm sac fertilizes the eggs, which are then deposited in a cocoon in the soil.

We tend to think of worms as being a few inches long. However, the biggest earthworm, the Gippsland Giant, found in Tasmania, can be as long as 10ft so, cut into sections, could support about 8 fishing trips. On the negative side, a worm cast it made in your lawn could cut out light in the kitchen.

At one point I was under the impression that worms are brilliant mimics. The one I kept as a pet, he was called Bert, could do being a rusty nail to perfection. I thought this was his crafty method of escaping detection. However, turns out it wasn’t. He’d been dead for a fortnight.

If anyone would like more information about worms (or other things pertaining to the garden), let me know in the ‘comments’ tag.


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