The report, entitled “Peat free, Quality free?”, in the January/February issue of the magazine, revealed the results of a series of trials on peat-free compost run last summer.
Using independent consultants to test the performance of 24 composts from four outlets across the UK for seed sowing and growing on seedlings or plug plants, Gardening Which? warned that there were “variable results between bags of the same compost bought from different parts of the UK”.
While one product – New Horizon's Organic and Peat Free Grow Bag – was rated as a “best buy” by the report for growing young plants, none of the products tested were rated “best buy” for sowing seeds.
The report even rated D-I-Y store Focus Multi Purpose Peat Free Compost as a “don't buy” claiming that it performed “poorly” in its young plants trial and seed trials.
Commenting on the study, the publication's editor, Ceri Thomas, said: “We've been testing composts for a quarter of a century at Gardening Which? and we are still astounded by the variable quality of peat-free composts.
“Compost manufacturers really need to up their game if they are going to produce compost that can balance the needs of the environment with the needs of our plants,”
she warned.
BBC
Following the study's publication, the head gardener for Radio Four's Gardening World programme, Alys Fowler, spoke out on the Today Programme against the use of peat-free compost.
She said on Friday (January 11): “It's early days for using green waste as a substitute for peat. Peat-free compost is not suitable for sowing seeds.” Ms Fowler also warned that shop-bought compost made from municipal green waste put out by the public had “varying qualities”.
Industry
Speaking to letsrecycle.com today, industry organisation The Composting Association insisted that 'reduced-peat composts' and 'peat-free composts' have successfully been made and trialled for both amateur and professional use in the UK.
It pointed out that many peat-free composts are now based on the PAS 100 industry standard.
However, Emily Nicholls, technical manager at the Association accepted that some peat-alternative composts and growing media available for sale were not formulated to be seed compost. And, she said 'grow bag composts' were not intended for sowing seeds as nutrient levels are usually too high to facilitate good germination.
Ms Nicholls advised: “Compost product information printed on the bag should make it clear what kinds of uses the growing medium is suitable for and how the product should be used. For example: 'seed compost for germinating seeds'.”
Although these products may need treating slightly differently to peat; the results are just as good when used for potting-on and planting up containers.
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