Peat sales went up in 2008 and peat-free sales fell, but Beardshaw wants other garden centres to follow B&Q's lead and stop selling products containing 100 per cent peat altogether.
He said: "The most important environmental issue that gardeners are now being made aware of is the need to know about the vulnerability of peat habitats."
He added: "Gardeners are trying to be green and encourage wildlife and nature, but peat is being extracted and that has the opposite effect."
B&Q said sales of peat-free products have increased 25 per cent year-on-year over the past 12 months. The chain said it has brought down peat-free prices in line with reduced-peat products, including its Peat-free Multipurpose Compost range (now from £2.98), Organic Living Peat-free Vegetable Compost (£4.98) and Organic Living Peat-free Growing Bag (£2.48).
Some grow-bags from B&Q contain 37 per cent non-peat products. Others are 100 per cent peat, supplied by Bord na Mona.
B&Q director of social responsibility Matt Sexton said: "So far this year, peat-free sales are doing tremendously well, with sales up over 75 per cent on this time last year.
"The sales of peat-free so far this year give me great optimism that we are making progress.
"I think that, for many years, people didn't understand what was in their compost or that using compost containing peat was leading to the destruction of irreplaceable peat bogs and natural habitats."
He added: "We've redesigned the packaging on all our compost so people can now clearly see what they are buying.
"We've also launched new peat-free alternatives and ensure their prices are aligned with those containing peat so there's no financial barrier to buying them," he explained.
"There's no doubt that environmental issues are also at the forefront of people's minds.
"Their concerns don't disappear when they go into their garden so I'm optimistic that more and more people will understand the implications of purchasing peat and instead opt to buy peat-free," Sexton explained.