Flies can be a nuisance in gardens and patios during summer, but an expert suggests a simple trick using coffee grounds and bicarbonate of soda instead of vinegar.
How Coffee Grounds and Bicarbonate of Soda Work
Mosh Latifi, co-owner of EcoCare Pest Management, told Ideal Homes that coffee grounds produce a powerful, bitter aroma that insects find unpleasant and masks attractants like food and carbon dioxide. Bicarbonate of soda, when mixed with an acid, produces carbon dioxide that confuses mosquitoes' tracking systems.
How to Use the Method
For best results, sprinkle bicarbonate of soda in and around rubbish bins or areas with lingering food odours. Place dry coffee grounds in a heatproof container and light them to smoulder. Position the container near seating areas, away from flammable items. The bicarbonate absorbs odours while coffee grounds smoulder, but flies may return once the smoke fades.
This method works best if the garden is cleaned, including emptying bins, cleaning spills, and removing fallen fruit. Latifi described it as a reasonable first line of defence for casual outdoor use, cheap and natural, but not a replacement for citronella candles or pheromone traps for serious mosquito pressure.
He particularly recommends burning coffee grounds for evening use when mosquito activity peaks.
Alternative Methods
Some suggest hanging bags of water from porches to reflect light and disrupt flies' sight, but this has limited effect. Fly traps using sugar and water can attract flies, but dead flies may attract more. Blue-light insect traps, based on a University of Florida study for the U.S. Department of Defence, attract flies; position them away from areas you want to keep pest-free.
