Appropriate that it should be St Patrick's Day when I saw the first slow-worm of the season, lounging around underneath a blackcurrant bush
Meanwhile, 'tis the season to start getting through vast amounts of potting compost, so I thought it would be a good time to recommend the things I've found useful.
The big problem with potting composts is that (in the UK at least) they're usually made of peat. I haven't knowingly bought peat since I stood on the summit of Croagh Patrick in the west of Ireland and saw the hideous gouges ripped across huge areas of what was otherwise a breathtakingly magical landscape. It really shocked and upset me. There's no shortage of beautiful scenery in Ireland, but even so, the destruction of vast areas for commercial peat extraction (mainly to feed an English addiction to cheap compost) is a sickening thing to behold. And since then I've tried to find a less environmentally damaging substitute ... with varying degrees of frustration.
Peat bogs are ancient and irreplaceable habitats supporting their own unique range of flora and fauna. They take hundreds of years to develop. Destruction of these ecosystems damages the wider environment too, because peat bogs play an important part in the spongelike absorption of carbon dioxide. Although Ireland suffers the brunt of the damage, peat-rich habitats in the UK and Europe are also being pillaged.
Things are going the right way, very slowly. The late lamented Geoff Hamilton outraged the peat industry more than a decade ago by urging BBC viewers not to buy it, and after his death Alan Titchmarsh took up the gauntlet. Retailers have started to work towards reducing or diluting peat products. But the reality is, despite the good example set by TV gardeners and recent government targets to reduce its use, most of the stuff available to buy in garden centres is either peat or it contains peat. Most people still buy it rather than put up with the hassle of finding substitutes. To make matters worse, many of the peat-free composts which have started to appear in recent years to cater for the environmentally-conscious are totally crap. Some go mouldy. Some are full of weed seeds. Some are so dense, stodgy and heavy they're unusable unless you mix them with something else. And they're often more expensive. No wonder so many people just buy the peat and stuff the environment.
Rainbow chard seedlings growing in pure coir
My compost preference has always been for the John Innes types, but I've been completely frustrated in my attempts to find a peat-free John Innes. It may be that somebody somewhere is making one, but I certainly can't find it at any garden centre in my local area. So these days I mix my own composts.
I started doing it as a last resort, after I bought a large bag of so-called multipurpose peat-free compost which turned out to consist of soggy black half-rotted tree bark which was so completely useless for its stated purpose it probably violated the 1968 Trade Descriptions Act. Rather than write to my MP in disgust or throw it away and buy something else I tried mixing it with horticultural sand and coir to break it up and aerate it a little. I ended up with a lovely compost ... and found the process of mixing it quite rewarding. It certainly wasn't any more trouble than driving down to my local soulless B&Q megastore and trying to hump bloody great bags of the ready-made stuff into the boot of the car. It only takes a couple of minutes and I make it up in small batches and adjust the mix for whatever I'm planting in it.
My basic compost recipe is just coir and sand with a sprinkle of fertiliser. It's a bit lazy but most things grow in it happily enough. For seed composts I often just use pure coir on its own, and that works well too. If I need something more specialised I might add perlite (for aeration), vermiculite (for extra moisture retention as well as aeration), coarse sand (for drainage), dried blood (for boosting leaf growth) or bonemeal (for growing good roots). Home-produced compost and leafmould are also excellent, though I can't produce either in very large quantities.
My basic material is coir bricks which I get from Chase Organics by mail order. They're lightweight and don't take up much space in the shed. They look rather like giant slabs of hash (I should be so lucky) but are actually made from compressed coconut fibre. They cost a couple of quid each and when you dunk them in warm water they mushroom into a great mound of fluffy compost, albeit with a rather odd resinous smell. And even when reconstituted they weigh less than most composts, which saves backache when lifting large pots around. They contain little or no nutrients, so I add that myself as and when it's necessary (for seeds you don't need it ... I just start watering them with a liquid fertiliser once they get established). Coir blocks are not the perfect earth-friendly solution ... they come from Sri Lanka and the Philippines and have to be flown in, but seem to me to be the lesser evil compared to peat. They're a by-product of the coconut industry and would otherwise go to waste.
Pipe dreams: no it's not a slab of finest pressed Moroccan, it's just a coir brick ... light, convenient and renewable
Also available from Chase Organics are these biodegradable coir pots called Green Start sets, a very fine alternative to the popular Jiffy-7 peat-pots. The pots themselves are formed from stringy coconut fibres, and have very good aeration and drainage. Each one comes with a compressed coir disc at the bottom. You just add a little water and within five minutes the tiny discs swell up to fill (and overflow from) the pots with compost. I tried them out last year and they gave me very good results. The open fibrous structure of the pots keeps the compost contained but allows the roots to grow through freely. They have an amazing ability to conserve water within the compost and stay dry on the outside while remaining very open and permeable.
Tomato seedlings growing in Green Start coir pots. Six pots fit snugly into a Tesco's mushroom punnet.
Whether coir is as good as or even better than peat is something that can be endlessly argued over, because it really depends what you're growing and what you expect from a compost. One of the disadvantages of peat is that it's difficult to reconstitute when it dries out and forms an impermeable crust on its surface ... coir doesn't have this problem. On the other hand, if you grow azaleas, coir can't compete with the natural acidity of peat.
Going completely peat free is a tricky matter because many of the plants you buy in the garden centre are still grown in peat. None of my local garden centres seem to stock peat-free container grown plants. One solution of course is to grow everything yourself from seed, and not buy container-grown plants at all, but that's not really the point ... it would be nice to be able to go out and buy a tray of pansies without having a guilt trip over it.
There is one peat-based product which is more or less environmentally sound, Moorland Gold, which is produced from peat and silt deposits built up from natural erosion by the filtration of water off the Yorkshire moors. It's high quality and I've heard a lot of good things about it. Local availability is another matter though.
The magnificent Eden Project has had a peat-free policy since its inception. The National Trust has adopted one. So has Kew Gardens. It's time the garden centres and manufacturers of composts got their act together ... but they won't do it unless consumer pressure forces them to.