June 9, 2014
South East Grower Reaps Benefits of Coir
Whichever way you look at the statistics, the expansion in UK soft fruit production since the turn of the millenium has been nothing short of phenomenal.
As the crop has moved under protection into Spanish tunnels and under glass, the area of strawberries has increased every year since 2002, to stand at more than 4,600ha.
The transfer has been accompanied by the move out of soil and, for more efficient picking, into tabletop and gutter systems that rely on substrates – at first peat, and latterly coir. “We have been moving over to coir for the last 10 years or so,” says Laurie Adams, production manager at Hall Hunter Partnership, which has seven production sites across the south-east of England. “It has been a gradual process, starting with a few acres, which has increased year on year and has gone hand in hand with the development of irrigation control technology.”
Mr Adams sources coir in various formats – compressed bagged ‘slabs’ which may be washed or buffered, blocks for pot production, and sometimes loose – and from a range of suppliers, including Dutch Plantin which has recently appointed the agronomy company Agrii as its UK distributor. Because of the substrate’s physical characteristics and high air content, plants readily take up nutrients and root growth is better, he says. “It is more forgiving than peat in terms of irrigation management,” he adds. “If it dries a little too much, you can quickly re-establish the optimum moisture content; and if it gets a little too wet, it is quicker to drain than peat.”
Coir’s ability to keep its structure over time means crop production is maintained for the life of the bag. “Generally we use a strawberry bag for three years but might replant it three times,” says Mr Adams. “The ‘slabs’ are all 1m long – the industry standard – and we specify a 20-litre volume in the main, more for everbearer crops because of their bigger root system. We opt for a standard pattern of drain holes so whatever the configuration of tabletop or gutter, we always have enough drainage.”
Mr Adams says 70% of the company’s strawberry production is now in coir. “We intend to convert fully over from soil,” he says. “We collect run-off from a few fields – and are looking at doing more – but at present we don’t reuse it, disposing of it through reed beds. We have, though, started to look at reverse osmosis and UV as ways of treating run-off with a view to reusing it.”
Raspberries, blackberries and blueberries are also grown in coir at Hall Hunter. “The raspberries are in pots for two years but with the new raspberry varieties that have been introduced, we may be able to keep them for three or four years,” he says. Blueberries are grown in a peat/coir mix and are repotted several times over their 10-year life.
The company is looking at overall production this year of 10,000 tonnes of soft fruit of which 8,000 tonnes will be strawberries.