Gardeners hoping to revive yellowing houseplants by burying a penny in the soil may be wasting their time, according to a new test. The popular hack, which claims copper from old coins acts as a fertiliser and fungicide, has been debunked as an old wives’ tale.
The theory suggests that copper leaches into the compost, providing a nutrient boost and warding off fungi. However, modern pennies contain very little copper, and even pre-1992 coins corrode too slowly to be effective. A trial comparing penny-treated pots with those on standard feed showed no difference in plant health after several months.
“The penny pots looked exactly the same, except for a greenish coin,” the report noted. Any changes in the plants were attributed to light, water, and photosynthesis, not the copper. Experts recommend saving pennies for the piggy bank and using a balanced fertiliser instead.
While the hack is harmless, it offers no real benefit. For a healthier houseplant, proper feeding and care remain the only reliable solution.
