On the surface, Karen and Boyd Turner's 27-hectare Wairau Valley lifestyle block is deceptively mundane.
A dozen beef cows meander through lush paddocks, relishing the good spring grass growth.
"There's not much to see here," says Karen as she wanders through an open gate past her vegetable garden to a strip of earth two metres by 12m, covered with old carpet underlay.
Hidden beneath the tattered, matted exterior, among rotting food scraps and horse manure, are the majority of her property's "livestock". Worms – thousands of them. They love the dark and moisture the underlay provides.
Tiger worms, a variety most distinguishable by their striped bodies, are Karen's fascination. "It's just amazing what they do."
Unlike normal garden worms, which live in a maze of tunnels beneath the surface, feeding on nutrients in the soil, "these fellas feed on the surface on rotting things", she says.
Every day, the bed is watered to keep the worms moist, while every fortnight the soil is turned over and aerated with a pitchfork. Worms do not like acidic bedding, so lime is also added to keep the pH of their surroundings neutral.
They are fed an array of rotting food, about six wheelbarrow loads, once a week.
After eating, they excrete a substance called vermicast. It is high in NPK (nitrogen, phosphorus and potassium) and is excellent for gardens.
Karen also points out some large plastic "water pods" nearby, which have been created to collect the liquid equivalent – "a combination of the worms' urine and the rain" – which leaches through the soil the worms live in and drips from a tap, to be collected in a bucket.
Karen and Boyd started their operation, Wairau Worms, in 2007 after purchasing 25 kilograms of worms from a North Island company called Worm Tech. She estimates that there are about 4000 worms per kilogram.
Back then, Boyd was working for the company from Blenheim, and it was his truck that helped to identify a hole in the market.
The truck's logo, which featured a worm, attracted plenty of attention from people wanting to know where they could get worms for their compost and gardens.
It took nearly six months before they got the operation up and running. It took time to set up the beds and get the worms breeding.
To breed, two worms, which "are AC/DC or hermaphrodites, tie themselves in knots" and fertilise each other. A mucus ring forms on the clitelum, a section of the worm more commonly referred to as the saddle. It slides off over the worm's head and forms a cocoon containing eggs, which take about three months to mature to adulthood.
