In Britain, there’s a huge pressure on gardeners to give up seed and potting composts (potting soil in the US) based on peat (peat moss). Digging peat for use in the garden is bad from the environment, it destroys valuable habitats. Here’s what the Royal Horticultural Society, which has reduced its peat consumption to 0.7% of all their growing media and soil conditioner, has to say on the issue:
“The RHS believes that the commercial extraction of peat at current rates is environmentally unsustainable as it removes peat at a much faster rate than it accumulates leading to the irreversible destruction of peatlands.
“Many viable peat alternatives exist which are either completely peat-free or of reduced peat content. With improved labelling and information on packaging, gardeners will be able to make more informed decisions about peat alternatives.”
The trouble is, peat makes the best medium for starting seeds (above, cick to enlarge - though we certainly don't need peat pots) and for growing on young plants. Which is why everyone uses it. And now it’s proven that most peat-free composts for starting seeds are a complete waste of money.
Which? Gardening - the highly respected, genuinely impartial magazine produced by the Consumers Association in Britain (similar to Consumer Reports in the US) - recently reported on their tests of seed composts. They tested ten composts intended for raising seeds, six based on peat and four without peat. Not only did the six peat-based composts fill the first six places, but two of the peat-free composts were so bad they were rated “Don’t Buy”.
Of one, Which? Gardening said: “The quality of our plants varied from reasonable to dreadful depending on the bag of compost we’d used. The worst seedlings barely grew at all…”
Of course at the RHS they have some of the finest horticulturalists in the world, they have the expertise, so can grow plants in almost anything! But it’s tougher for the rest of us especially when, as Which? Gardening found, even different bags of the same brand of compost can vary enormously.
However, it’s also worth pointing out that when Which? Gardening tested composts for containers, two out of three of their Best Buy composts were peat-free. That’s great news - but not much help if your seedlings never get to planting size.
In the end, I expect some excellent products to be developed. But this is surely a case where government sponsored research could help gardeners and compost producers alike, for the greater good – the environment in general. The producers themselves have clearly not done much of a job so far - for seed composts anyway.
Oh, and by the way. Fresh sphagnum moss (above right, click to enlarge), the progenitor of peat, collected from the wild for orchids and to line hanging baskets? No. There are plenty of good alternatives that really do work.
Seeds might suffer if peat free compost is used but it's not really sustainable to continue cutting peat for use in compost. Went to Ireland last summer where they still burn peat (or turf!) and it does make a complete mess when it is dug up.
Posted by: Gordon Rigg | February 28, 2012 at 05:42 AM
Thanks for the article. People (like me) have gardened without peat for thousands of years. I question the results of that study, but even if it was well-conducted, we certainly don't need peat. I use the basic seed-starting mixture of sand, soil and compost, or sometimes even just soil and compost, with decent results. Thanks again.
Posted by: Phil (Smiling Gardener) | February 28, 2012 at 09:05 AM
Well Phil, I would expect studies by Which? to be carried out very well. They've been doing this sort of thing for years, they know what they're doing. And if they say that two brands of peat-free seed starting compost are so bad that their recommendation is "Don't Buy" then I trust what they report.
My feeling is that using peat as a soil improver is ridiculous, there are plenty of other bulky organics that will do the same job. Which?, as I mentioned, have rated two peat-free mixes for containers as "Best Buy" - so we're OK for containers as long as we choose the right brands.
But I'm not going to waste money on seeds by sowing them in wildly unpredictable peat-free seed starting mixes. I want to be sure my seeds come up. And after I've started my seeds in peat-based compost I'll then use the compost for growing on, then in containers and finally on the garden. That's four uses for it. But as soon as we have reliable peat-free seed starting mixes I'll be the first to cheer.
Posted by: Graham Rice | February 28, 2012 at 04:21 PM
Rather belatedly sitting down with the February issue of the RHS magazine The Garden, and I find there's a piece by RHS propagation wizard Nick Morgan - about how to adapt and improve peat-free seed composts so that your seed actually comes up and your cuttings root! http://tinyurl.com/86l5bbe Well worth reading.
Posted by: Graham Rice | February 28, 2012 at 04:36 PM
Such a brilliant idea! I truly agree with you on government sponsored research could help gardeners and compost producers alike, for the greater good – the environment in general. Thank you for such an informative post :-)
Posted by: John | February 29, 2012 at 09:59 AM
Thanks for your comments Graham and the link to the article. My main thought was that people around the world have been starting seeds without peat forever, and it clearly works. But I agree there are a lot of poor potting mixes out there, and perhaps that was the main gist of your article. Thanks again. I'm going to read that article now.
Posted by: Phil (Smiling Gardener) | March 03, 2012 at 03:59 PM
A recent copy of 'The Garden' showed the comparable results of trials of non-peat composts but there was no 'control' sowing in a peat-based compost. If they had done so I think it would have shown what comparatively poor results non-peat composts often give. The use of peat for horticulture is minimal compared to other worldwide uses and much of our peat is imported anyway.
Posted by: Ian Cooke | March 10, 2012 at 05:08 AM