Houseplant hacks: does washing-up liquid get rid of pests?

It can work wonders on aphids but won’t conquer tough infestations such as mealybugs – and be careful not to scorch the leaves

The problem
Few things test a plant-lover’s patience like a pest infestation. The internet is full of DIY advice, and one of the most popular tips is to mix washing-up liquid with water and use it as a pest spray. It’s cheap, easy and always within reach. But it’s not without risk.

The hack
A diluted detergent solution is said to break down the waxy coating of soft-bodied pests, dehydrating them on contact. It can work wonders on aphids, spider mites and thrips, killing them quickly without the need for harsh chemicals. But household detergents weren’t made for plants. The wrong formula or a heavy hand can cause serious leaf burn, leaving behind residue that stresses your plant more than the pests did.