Thrips are a common but often misunderstood pest that can cause significant damage to houseplants and indoor cultivation. They are small, fast-moving and easy to miss at the early stages of an infestation. With the right knowledge, however, they can be detected in time and controlled effectively.
What do thrips look like?
Thrips are very small insects, usually only one to two millimetres long. They have a narrow, elongated body and can be light yellow, brown or almost black depending on species and age. Adult individuals have narrow wings that lie close to the body, while the larvae lack wings and are even lighter in colour.
Because thrips prefer to hide on the undersides of leaves, in leaf folds or inside buds, they can be difficult to see with the naked eye. A common sign is instead the damage they leave behind. Affected leaves often develop silvery or greyish patches, small dots or a dull and dry appearance. Sometimes small black dots can also be seen, which are the droppings of the thrips.
Why thrips are a problem indoors
Thrips suck sap from the leaves and damage the plant’s cells. This leads to reduced growth, unsightly leaves and, in the worst case, the plant losing leaves or flowers. Indoors, thrips thrive particularly well because the environment is often warm and dry, especially during the winter months. They reproduce quickly and a small infestation can become extensive in a short time.
How to control thrips indoors
The first step is to isolate affected plants as soon as you suspect thrips. This reduces the risk of the pest spreading to other plants.
Start by thoroughly showering the plant with lukewarm water. This washes away many adult thrips and larvae. Be especially careful with the undersides of the leaves and new shoots. Repeat the showering regularly.
The next step is treatment. Insect soap or soapy water is a common and gentle option that works well for lighter infestations. Spray the entire plant and repeat the treatment several times at intervals of a few days, as new larvae hatch continuously.
In cases of more severe infestations, beneficial insects can be an effective and natural choice. Predatory mites and other biological enemies are often used in indoor cultivation and greenhouses to keep thrips populations under control.
Increasing humidity can also help, as thrips prefer dry air. At the same time, it is important to continue checking the plants regularly, even after the infestation appears to be gone.
Author: Emma Vogiatzi – Gardener
Fact-checked by: Erik Hoekstra
Last updated: 2026-02-05