USA – cranberry waste makes useful growing medium

They‘‘re a favorite Thanksgiving side dish, praised for their health benefits and the source of a roughly US$70 million industry. Now, Massachusetts cranberries are being lauded for something far less glamorous: their waste.



The Nashua Telegraph reports that confronted with mounting piles of cranberry skins left over from Ocean Spray‘‘s juice processing facility in Middleborough, the man who manages and hauls away the fruity remains turned to University of Massachusetts researchers to see if the scraps could be put to use rather than being dumped in landfills. The scientists realized the shredded skins – called pomace – have a lot in common with peat moss. After composting the pink sawdust-like material into an earthy brown substance that smells like dirt and has the consistency of pipe tobacco, the researchers began adding it in place of peat moss to potting mixtures for petunias, poinsettias and mums.



“Nobody ever looked into this before because it was just a lot easier and cheaper to throw the pomace out in the dump, ” said Paul Lopes, one of the researchers with the UMass extension program.



And Ocean Spray – which spends more than US$100,000 to have five tons of pomace hauled away each year – is curious to see if the researchers‘‘ continued experiments will prove marketable. “If somebody would pay to take it from us, that would be good economics, ” said company spokesman Chris Phillips. The pomace could also make better financial sense for commercial flower growers. While peat moss grows in abundance in Canadian bogs, its price fluctuates against the strength of the American dollar and the weather during harvesting season.



The idea of adding agricultural waste products to potting mixes isn‘‘t new. Pine bark, coconut husks and peanut shells have all mingled with peat moss and served growers well. And this isn‘‘t the first time cranberry waste has been recycled. Some of Ocean Spray‘‘s fresh pomace has been finding its way to mulch producers in southeastern Massachusetts for a few years, although it hasn‘‘t been a big moneymaker for the company.



“I had this idea that maybe this stuff might be useful, ” said Scott McLane, the recycling manager for Plymouth-based Howland Disposal, which has been carting away Ocean Spray‘‘s pomace since 2001.



After helping broker deals between wholesale mulch producers and Ocean Spray, a friend of McLane‘‘s in the nursery business suggested he investigate whether the pomace had potential in the gardening industry.



“It showed promise, but nursery people can‘‘t use large quantities of this and find out later that it‘‘s spawning diseases and creating problems and making them lose money, ” McLane said. “We needed to research this and show it was safe and beneficial. “



Enter Lopes and his fellow UMass researchers, Tina Smith and Douglas Cox. The team began working with a handful of Massachusetts flower growers, who agreed to experiment with the composted pomace.



So far, the stuff seems to work best when it‘‘s added in a 50-50 mixture with peat moss. Too much pomace hurts a growing plant‘‘s root system and seems to prevent flowers from blooming properly, most likely because of the cranberry‘‘s high acidity.



While the UMass researchers are still trying to create the best concoction before it can be marketed, the pomace is so far getting good reviews from the commercial flower growers they‘‘ve been working with.



Terry Lyons, a greenhouse owner in Foxborough, said he used a 50-50 pomace mix to grow a few dozen garden mums and hanging petunias.



“There‘‘s no difference at all between using that and straight peat moss, ” he said. “If pomace were par