Mower or less Cut the cuts and let your lawn thrive

WE gardeners can contribute to the climate emergency by reducing our emissions as well as growing CO2 absorbing plants. So our gardening methods shouldn’t undermine the benefits of our perennial plantings.

We’re all guilty of using gadgets around the garden: lawnmowers, hedge trimmers, strimmers and shredders, to name a few. And to a greater or lesser extent, they all contribute to carbon emissions.

A study by the American Environment Protection Agency published last year demonstrated the extent of the problem. They found that garden machinery alone was responsible for 4% of CO2 emissions in the US.

This included everything we don’t normally think about: energy production and transport costs together with their ongoing maintenance and fuel consumption. It’s unrealistic to suggest abandoning this laboursaving equipment, but we can and should use it less often and choose more environmentally-friendly tools, like hand-powered or electric mowers and hedge trimmers, not petrol ones.

Take a lawn. We’ve transformed natural grassland, an important carbon sink, into the garden’s most energy-guzzling, carbon-emitting culprit. This was borne out by a Swedish study five years ago. Researchers found that greens and fairways on two golf courses emitted large quantities of CO2 but the root systems in the roughs sequestered carbon.

The Swedes found that fertilisers on the golf courses were especially damaging, as is any nitrogen fertiliser anywhere in the garden. Huge quantities of energy are expended in nitrogen production. David Wolfe, professor of Plant and Soil Ecology, Cornell University, noted last year that for every ton of nitrogen fertiliser, 4-6 tons of carbon are released.

Since these fertilisers produce much more nitrogen than our grass or other plants can use, soil microorganisms convert excess nitrogen into nitrous oxide, N2O. This gas has 300 times more heattrapping ability than CO2.

By not using fertilisers and herbicides, you also eliminate packaging and transport costs.

So how do you maintain a healthy lawn? Start by recognising that a uniformly bright green sward is unnatural and frankly boring. A diverse lawn, containing dozens of different species and, dare I say it, a few weeds, is much more resilient and doesn’t need cosseting.

Let the lawn feed itself. During a dry spell, take a high cut and let the clippings rot back into the soil. Alternatively and preferably, you could use a mulching mower, so the grass is instantly restored to the soil. This second method eliminates the small amount of carbon released by clippings.

A real lawn needs no pampering, so there’s no watering even during a dry spell. Like prairie grassland scorched by sun or fire, the lawn will recover. By not squandering good quality drinking water on a bit of ego-boosting grass, you

cut back on the energy used in its preparation.

If you find grass cutting a chore, as well as reducing feeding and watering, cut it less often. Not only do you reduce CO2 emissions, but you greatly increase garden biodiversity which cheers and absorbs us during these dark Covid-19 days.

The charity Plantlife is running a Citizen Science project. Gardeners are asked to see what happens when they don’t cut at least part of their grass in May, letting it grow to 8-10cm. They should select their trial spot by throwing a ball in the air and marking a metre square quadrat where it lands.

During the week of May 23, participants are asked to count the number and variety of flowering plants and enter their results online. They will then be provided with a ‘nectar count’, a rough assessment of the value to pollinating insects. See www. plantlife.org.uk

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