Tiger worm vermicomposting trial 'shows promise'

Otago Polytechnic's horticulture production Level 5 co-ordinator Jason Barry. Photo / Yvonne O'Hara

Hungry tiger worms are making short work of shredded sheep pelts and the resulting vermicast output is significantly improving growth in trial plots of pasture grass, and a barley and pea blend.

Cromwell's Central Wormworx Ltd owner Robbie Dick and Otago Polytechnic's horticulture production Level 5 co-ordinator Jason Barry are running a vermicomposting trial to see if the castings produced by sheepskin-fed worms are an effective soil conditioner as well as encouraging plant growth and providing a recycling option for sheep skin waste.

If it proved successful, they hoped to attract funding to carry out further research.

Dick said he added shredded sheep pelts from meat processing plants, along with cardboard and dairy farm waste, to his worms' diet on August 12.

The cardboard and pelts, which are usually dumped in landfill, were covered with a layer of soil, and the worms disposed of it in about two weeks.

"Cardboard is also something else we have in abundance and the more variety [of diet] we feed them, the better the castings quality."

Barry said he intended to use the trial site at the polytechnic's Bannockburn campus to plant apple trees later this year.

The polytechnic made land and labour available for the trial and contributed to the cost of the vermicastings.

However, as the site had poor soil, and was free draining, with low fertility and organic matter levels, he decided to trial the vermicast before planting the trees.

He prepared the four 15m × 2.7m beds on November 25 and sowed them the following day.

Two plots had perennial ryegrass, one of which was a control.