11 January 2008
Compost producers need to up their game in order to produce good quality, peat-free composts that live up to their peat-based counterparts, according to new research by Gardening Which?.
Despite Government targets requiring compost manufacturers to go virtually peat free by 2010*, Gardening Which? tests show there is still a way to go before reliable quality peat-free composts are produced. There remains a large gulf between the performance of peat-free and peat-based composts for growing young plants from seed.
New Horizon Organic and Peat Free Grow Bag was the only peat-free compost deemed to be a Best Buy for growing-on young plants.
Variable results in quality between bags of the same compost bought from different parts of the UK meant it wasn’t possible make any peat-free compost a Best Buy for sowing seeds .
Focus Multi Purpose Peat Free compost was rated a ‘Don’t Buy’, scoring only 8 per cent overall, and performing badly in both the young plant trial and seed sowing trials.**
Traditional peat-based compost continued to top all the trials, with B&Q performing best. B&Q’s Seeds, Seedlings and Cuttings compost scored 88 per cent and was awarded Best Buy status in the seed sowing tests, while B&Q’s John Innes No.2 was the top scoring compost in the young plant trial. This was also awarded a Best Buy and scored 83 per cent overall.
Ceri Thomas, Gardening Which? editor, says:
“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 products.
“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.”
-Ends-
For further information, a PDF of the full report, images for reproduction, or an interview with Gardening Which?, contact Rebecca Leach
Gardening Which? is a subscription-only gardening magazine published 10 times a year by Which? For details on how to receive 3 issues of Gardening Which? for £3, telephone 01992 822800 or visit which.co.uk
* By 2010, The UK Government has set a target for 90 per cent of the soil improver and compost market to be made up of non-peat materials.
** Focus Multi Purpose Peat Free Compost performed badly in seed-sowing and young plant trials. Seedling size and quality was very poor, and the young antirrhinums and cabbages were looking sickly after six weeks, receiving poor ratings for plant size and quality
An independent test site assessed the performance of 24 composts for seed sowing and growing on seedlings or plug plants. Gardening Which? chose tricky to germinate impatiens and fertiliser-sensitive petunia, and sowed 25 seeds in twelve pots of each compost and assessed the rate of germination and the size and quality of the resulting seedlings.
Gardening Which? also grew young plants of fertilizer sensitive antirrhinum and greedy cabbages in twenty pots of each compost. They were assessed for colour, size and vigour after six weeks without any additional feed. Previous trials have shown differences between bags of the same compost, so Gardening Which? tested bags of compost that were bought in four different regional areas of the UK.
