Sorting the snake oil from the genuinely sustainable is made even more difficult because there’s so little scientific research into how “natural” products work in a real-world garden, Look closer and much “evidence” backing up eco-friendly gardening concoctions, whether home -made remedies or hi-tech inoculants, is anecdotal at best.
“Organic products have a mythical element,” says Kevin Beaty, owner of EcoGro, which produces liquid plant feeds from renewable energy powered by, well, cow poo.
“It’s essentially liquid farmyard manure,” he says. “But we’ve only done our own tests – we’re a small company.”
Claims are made for more high-profile natural products such as biochar – a form of carbonised wood that sequesters carbon and, allegedly, improves soil quality. “The bottom line is there’s not much evidence that it does anything,” says Dr Thompson. “If you start with a pile of wood with no nutrients, turning it into biochar won’t add any extra.”
There is proof that plants grow better in contact with mycorrhizal fungi, which help roots access nutrients in the soil. But healthy soils are already seeing with mycorrhizae, and there’s scant evidence it makes any difference to add more artificially. Tests of mycorrhizal fungi inoculants by Which? Gardening were inconclusive and suggested that building soil fertility by mulching with organic matter may be just as effective.
“It used to be that if it’s green it’s expensive and it doesn’t work,” says Andy Hiron, managing director at Envii, which harnesses naturally occurring bacteria to create garden fertilizers.
But he believes that trying to develop greener products is still progress of a sort – and a lot better than carrying on using damaging products. “Sometimes you have to say it’s the right thing to do. It’s not easy, but I’m not sure there’s an alternative.”
Even genuinely green products can inflict collateral damage if they’re packaged in plastic, or transported halfway across the world. Coir, jute and Hessian, for example, are biodegradable materials: coir is mainly a peat substitute; jute is used to replace nylon twine and also for biodegradable pea netting; Hessian sacks are used for storing potatoes and it is occasionally recommended for lining pond containers. (You can also plant pond plants wrapped in Hessian with no plastic container required).
I wouldn’t necessarily use hessian to replace fleece as it’s a little heavy for most uses, though I might use it for temporary frost protection if I’m wrapping a plant. I’ve also used hessian sacks as biodegradable grow bags successfully. However, and here is the downside: these materials come all the way from south Asia to get to my garden shed.
Hemp twine is more locally produced (mainly in France); Twool, spun from sheep’s fleeces in Devon, is also surprisingly strong and even closer to home.
But there’s really no point in buying biodegradable pots from the garden center if they’re wrapped in unrecyclable, single-use cardboard cellophane: it baffles me why, as if you order online they arrive in simple sleeves. You can usually find products packaged in boxes rather than rigid plastic tubs; but it’s difficult to supply liquids, whether feeds or pesticides, in anything other than a plastic bottle.
There are less plastic-hungry alternatives, though. Hiron is moving his Maximato tomato feed from a liquid to a concentrated soluble powder. “Then it’s a letter, not a parcel, so you’ve saved 450g packaging right there,” he says. “We try to make things as small and light as possible.”
Mail order is often the only way to get hold of more niche green products that your garden center doesn’t stock. But it can leave you with a huge pile of unrecyclable, single-use plastic to deal with if you’re not careful, from bubble wrap to packing tape.
Responsible companies will pack in cardboard, and use padded envelopes stuffed with recycled paper – and they’ll usually shout about this on the website, so it’s not difficult to check.
Winkling out the truly green gardening products is hard work, involving painstaking research, careful sourcing, and a good dollop of skepticism. Even when you think you’ve found something that’s both eco-friendly and effective, you can be blindsided by new information.
Ferrous phosphate slug bait was hailed as the wildlife-friendly successor to soon-to-be banned metaldehyde, and was proven in RHS trials to be almost as effective. But then research emerged showing that the chelating agent it contains, EDTA, may harm earthworms.
However, this in turn is now out of date: most brands, including market leader Growing Success, say they’ve replaced the EDTA with “naturally occurring fertilizers” instead.
Truth be told, the only really green shopping is not shopping at all. There’s no need to buy soil fertility activators or mycorrhizal fungi if you’re feeding your soil with organic matter.
You won’t need plastic bottles of liquid feed, either, if you have a comfrey patch or a stand of nettles to make your own.
I make biodegradable pots from recycled newspaper and cardboard, and strip the leaves of my New Zealand flax into strong filaments to tie up my tomatoes. It may not be hi-tech, but it works for me – and the planet, too.
Sally Nex, gardener and writer, lives in Somerset. Her book of her, How to Garden the Low Carbon Way (RHS/Dorling Kindersley), is available to buy.
How to shop sustainably
- Only buy if you really have to – ask yourself if you could get by without it – and if the answer is yes, don’t buy.
- Buy second hand if you can – online auctions, Facebook Marketplace and reclamation yards are all happy hunting grounds for pots, tools and garden furniture.
- Source locally – the closer to you a product is made, the lower its carbon footprint.
- Look for independent accreditation – Soil Association badges, or approval by the Organic Farmers & Growers is reassurance that organic means organic.
- Do your research – look up active ingredients and search for independent trials and studies to back up environmental claims.
Top tips for repurposing plastic
Reuse to take green waste to the tip, grow potatoes in sacks, or line terracotta pots to prevent them drying out too quickly.
Reuse for as long as possible, then recycle at a garden center that offers recycling facilities (not your local tip as most don’t accept them – whatever color they are). Then replace with biodegradable alternatives made from bamboo or coir.
Best environmentally friendly garden products to buy
Buy with a clear conscience
George Holan is chief editor at Plainsmen Post and has articles published in many notable publications in the last decade.