There’s been a lot in the news lately about peat-based multipurpose compost being banned from sale by garden centres, because the industry’s attempts to phase it out by 2020 didn’t work.
We’ve only been using it in multipurpose compost for growing plants for seventy years or so, since the mid 1940s. Up till then, gardeners and growers made their own compost from leaf mould, garden compost (= the stuff you make with garden waste and vegetable trimmings), sand, grit – there were many recipes, with very variable results. Once peat started to be used in commercially-made composts, they could be standardised; peat retains air at the same time as it retains water, unlike most other materials in use up till then. It’s light, it’s cheap to extract and it’s sterile (growing media have to be free of disease and weed seeds), so it’s reliable and risk free. And it can be used in machinery to produce thousands of plug plants at a time, which supports garden centres and some nurseries.
But there’s a downside.
Peat is hugely important, partly because it’s a unique habitat that takes thousands of years to produce, and partly because it stores massive amounts of carbon, which is released as carbon dioxide when it’s dug up. Digging up a peat bog is like cutting down a rainforest.
The peat dug up for just one year’s worth of multipurpose compost in Britain alone releases half a million tonnes of carbon dioxide, which is equivalent to about a hundred thousand cars on the road.
Over time, it has become completely normal to just go and buy a bag of multipurpose compost to start plants off, or to grow plants in pots, hanging baskets or containers; and many veg growers will start plants off in it, and just want to buy the cheapest. It’s been very hard to persuade people to change from what they’re familiar with, particularly when the alternative is a little more expensive.
There are now many different types of peat-free compost, often based on wood, coir (the fibre on coconut shells) or green waste; some of them are very good indeed. But non-peat growing media account for less than 30% of the total market, and peat is still being dug out of the ground.
The government decided in 2011 not to introduce legislation, as it felt the industry could gradually phase peat out on its own, voluntarily. Recent government advice was “We encourage people to go peat free”.
There are other ways of avoiding peat, of course – you can garden well without buying compost at all, and that way, you also don’t need to buy fertilisers to top it up when it runs out after six weeks. But that doesn’t work for starting seeds off, or bringing plants on before planting them out, which accounts for a lot of the compost sold. We’ll be looking at solutions to this over the next few months.