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Plastic Free July: The hidden plastics in your garden and how to ditch them
- 8 hours ago
- 3 min read
Compost, fertilisers and even turf may all contain plastic elements.
For many gardeners, the plastic elements used in horticulture are obvious – black plastic pots and seed trays, artificial grass and some membranes, to name but a few.
But what about the hidden plastics in your garden, the microplastics we don’t really consider which might eventually leach into our soil? And how can we ditch them?
So, where are the hidden plastics – and what are the alternatives?
1. Synthetic coated fertiliser
Coated granules which offer ‘slow release’ or ‘controlled release’ are often covered in plastic.
“Most fertilisers on the market at the moment are sold with a plastic coating, so when the fertiliser is used up, you are left with the plastic coating in the soil,” says RHS chief horticulturist Guy Barter.
“However, under pressure from the European Union, manufacturers are phasing out the plastics and introducing natural waxes and oils instead.”
Solution: Opt for organic slow-release fertilisers such as fish, blood and bone, or organic chicken pellets, or plant-based alternatives including seaweed. Grow green manure crops such as crimson clover, field beans, mustard and buckwheat in vacant spots in your garden to enrich the soil.
2. Weed-suppressant membrane
Most are obviously plastic, but some gardeners don’t consider that they will break down and end up in our soil.
“The cheap stuff just breaks up and disintegrates into the ground and is horrendous, but most people don’t see that,” says Zoe Pink, owner of garden design and landscaping company Hortus Pink Landscapes.
“The thing with membranes, especially the cheap ones, is that roots grow in them, on them and through them. People also slice holes through them to plant into them. It’s a massive false economy.”
Solutions: Include more ground cover plants in your border to discourage weeds and follow a ‘no dig’ policy because digging a border encourages weeds, and mulch annually with organic matter.
3. Horticultural fleece
“Sometimes people think horticultural fleece is wool because it’s called fleece,” says Barter. “You get some people selling wool products saying this is fleece, but it doesn’t have the same thermal properties as the plastic fleece.”
Solution: Protect vulnerable plants with glass cloches and cold frames, or move them into sheltered positions in a shed or greenhouse during the colder months and wrap the rootball and the whole plant with straw, secured with chicken wire, which can be recycled.
4. Compost
Bought compost may contain plastic contaminants and residual fragments of packaging and labels, if you are not fussy about your source.
“If you buy from your local council you have no idea what’s in it,” says Pink. “People could be putting all sorts of nasties into their green bins and it all gets churned up. I never buy council waste, I always buy professional-grade commercial compost that has had the manufacturing process for you to have a clean product.”
“The best compost is made from wood fibre, coir and bark,” Barter continues. “Those would probably have a very small plastic content, but the cheaper fertilisers and some soil improvers are made from municipal waste, which is composted stuff from the green waste bins and the food waste bins and such like, and there is almost certainly a significant level of plastic contamination.”
If you make your own compost, avoid adding teabags because some contain polypropylene or nylon, leaving little plastic fragments in the soil, he advises.
Solution: Go for more expensive potting compost which is reliably sourced and, if you are going to add teabags to your compost, make sure they are biodegradable, made from paper.
5. Cardboard and carpets
Some gardeners use cardboard as an alternative weed suppressant, or to cover their compost heap, but some cardboard has a polythene lining to seal it. Others will cover their heap or soil with old carpet, but even the woollen ones might have plastic-based glues, warns Barter.
Solution: Only use the coarsest, most open, cardboard to reduce the risk of adding polythene to your compost bin and avoid covering it – or the ground – with carpet.
6. Turf
“When you buy cheap lawn turf, you may see a plastic membrane underneath it,” says Barter. This enables producers to cut the turf much thinner, with less soil and root underneath it and makes it cheaper to transport and quicker to lay, he explains.
Solution: Go to retailers who are members of The Turfgrass Growers Association, which is banning the use of plastic netting in turf production by its members from October 31 this year.
