Gardeners Are Being Urged Not To Use This Common Kitchen Liquid on Their Lawns: 'I Won't...'
Gardening enthusiast Danny from Deep South Homestead (@DeepSouthHomestead) waited through the 2018 fall to watch the roasted pepper and bell pepper plants thrive in his greenhouse. Aware that peppers could easily get infested by aphids, he scoured the internet for advice on how to protect the plants. Following a tip shared by tons of people, he invested in a bottle of soapy dishwashing liquid and sprayed it on his peppers. But instead of warding off the party of insects, the liquid ended up killing his plants. In January 2019, he shared a video showing how his lively peppers were on the verge of death. “I won’t use soapy water again,” disappointed and angry, Danny told the viewers.
Danny’s story is just one example of how even the best intentions of a plant-lover don’t work out well if they’re watering their plants with soap-filled liquid. This is not to vilify the usefulness of dishwashing liquids, for they're good in their own way, but to note that a dish soap might not be the most appropriate recipe to protect or hydrate the plants, as horticulturist Sophie Willoughby, a garden expert, told The Mirror. “Washing-up water often contains surfactants and phosphate, chemicals that are great at lifting grease off plates, but terrible for your lawn,” she explained.
Willoughby explicated that the foamy soap liquid can strip away healthy ingredients and organisms from the soil while also making it less responsive to water. Over time, this can cause the plant to become thirsty and dehydrated. “Any soap will contain salts, which will absorb water and dry out the plants. Most plants like peas, tomatoes, and fruits will show effects of the above very quickly, hardy plants might be difficult to kill,” a Reddit user, u/Mayank_j, explained in a post. This also goes true with Danny’s case. The dishwashing liquid didn’t attack his yellow Marconi’s, the hardy plant, but only the sensitive pepper plants.
One reason could be the harsh chemicals locked in the dish soap that might be acting as growth disruptors for plants, as master gardener Mary Jane Duford explained to The Spruce. The dish soap, Duford said, breaks down the outer membranes of soft-bodied insects, but the synthetic chemicals it releases in the process can prove to be harmful to the plants. It might be tempting to think that this cheap soapy solution can be used as a homemade pesticide, but ultimately, it does more harm than good.
“Dish soap often contains synthetic surfactants and solvents that strip oil. This is great when washing dishes, but it also strips the natural oils from plant leaves, leading to leaf burn, drying, and other damage,” said Duford. Particularly those soaps that contain thick oils, they can form an oily veneer on the soil’s surface and block the pores to an extent that they won’t be able to absorb sunlight anymore.
This, however, doesn’t mean that gardeners can never use dishwashing soaps to kill the bugs invading their plants. The trick is to use them sparingly and to not leave them on the plants for too long. Take a few little droplets of the liquid and spray them on the plants. Once they have squooshed away the invaders, once again rinse the plants by splashing and blasting lots of water so the chemicals, together with the bugs, are washed away. A soapy solution is typically good for evading soft-bodied buggy visitors like spider mites, aphids, whiteflies, mealybugs, boxelder bugs, and Japanese beetles.
Although Duford includes aphids in the list, it is inexplicable why Danny’s pepper plants started dying after he sprayed this soapy solution. Timing could be a possible reason. Another reason could be, pepper comes under the category of a food crop. In that case, the expert recommended sticking “with EPA-approved insecticides labelled for use on edible crops.” Alternatively, Duford suggested using an “insecticidal soap.”