As the UK braces for another heatwave with temperatures soaring to 34C, Gardeners' World presenter Monty Don has issued a crucial lawn care warning to gardeners across the country. With forecasts predicting highs of 34C or above, many households are preparing for barbecues and gatherings, but Don advises against mowing lawns during this period.
Heatwave Alert and Lawn Care Advice
Amber heat health alerts have been issued for the East, South East, and South West of England, as well as London, running from Thursday at 12pm through Tuesday at 8pm. While gardens have benefited from recent rainfall, the upcoming scorching temperatures pose a risk to lawns. Monty Don strongly recommends refraining from mowing until at least 21 June, the summer solstice, to protect grass and wildlife.
The primary advantage of allowing grass to grow longer is a healthier garden next spring. Don explains: "By June a million gardens are regularly humming with the sound of motor-mowers. But at Longmeadow we restrict this to paths and let as much grass as possible grow long, planted with spring bulbs and wildflowers. This looks beautiful and is better for insects and wildlife than a neatly mown lawn."
Timing the First Cut
Don emphasizes that nothing should be cut until after the longest day on June 21st. This allows bulb foliage to die back and feed next year's growth. The grass can then be cut if it has been hot and dry, though Don sometimes leaves it until mid-August. He advises collecting all clippings for the compost heap to prevent adding nutrition that encourages coarser grasses.
Jonathan Davis, a grass specialist at Lawnsmith, echoes this view: "Importantly, no one should be cutting their grass this weekend. While it might seem like a good idea, the best thing you can do is leave your lawn alone during heatwave conditions. Cutting it during hot weather can stress the blades and lead to long-term damage."
If You Must Mow
Davis advises that if mowing is unavoidable, it should be done before 10 am when temperatures are cooler. Mower blades should be raised to the highest setting, keeping grass around three to four inches long. "Longer grass blades create a shadow that helps keep moisture in your soil," he adds.
Temperature Forecast
Areas across the south and South East are expected to reach heatwave criteria over the weekend, with a 40% probability of surpassing the record June temperature of 35.6C set in 1957 and 1976. East Anglia could see 32C on Friday, followed by a brief dip to 28C on Saturday. However, temperatures will climb again, hitting 32C on Sunday and potentially 34C or higher on Monday.
Met Office meteorologist Alex Deakin describes these temperatures as "pretty unusual even for the middle part of June." There is also a slight chance of thunderstorms in the South East and East Anglia on Sunday. Deputy chief forecaster Gregory Wolverson warns that cloud cover and high humidity could make conditions feel "rather oppressive at times."
Health Warnings
The UK Health Security Agency's amber health warning indicates an increased demand on health and social care services, potentially leading to a rise in deaths. Those aged 65 and over and individuals with pre-existing health conditions are most at risk, though younger age groups may also be affected. Less severe yellow alerts have been issued for the East and West Midlands.
The Met Office defines a heatwave as three consecutive days where daily maximum temperatures meet or exceed a location-specific threshold.
