To get rid of spider mites on houseplants, you need to physically remove the existing population and then treat with an appropriate spray, repeated multiple times over two to three weeks to catch new hatchlings. Spider mites are very small and spread quickly between plants; catching an infestation early and treating it systematically is significantly easier than dealing with a heavily infested plant or a collection that has been exposed. A single treatment is almost never sufficient, as eggs are resistant to most contact treatments and will hatch within a few days of the initial spray.
How to Identify Spider Mites
Spider mites are too small to see individually without magnification, but their damage and webbing are visible. The first sign is pale stippling or silvery speckling on the upper leaf surface, each tiny spot is where a mite has pierced a leaf cell and extracted its contents. As the infestation progresses, you will see fine webbing on the undersides of leaves and in the gaps between leaves and stems. In a heavy infestation, the webbing can be extensive and the plant can look dusty or dirty. Moving a heavily infested leaf and looking closely reveals the mites as tiny moving dots.
Checking the undersides of leaves regularly, at least every two weeks, is the most reliable way to catch spider mites before they establish. Look for speckling on the upper surface and fine webbing on the underside, particularly along the central vein.
Immediate Steps When You Find Spider Mites
Isolate the affected plant immediately, away from your other plants. Spider mites spread by contact and by being carried on clothing or tools. Even a few days of contact with neighbouring plants can establish a new population.
Give the plant a thorough shower or wipe-down. Take it to the sink or shower, support the pot, and wash the entire plant thoroughly with a lukewarm water jet directed at the undersides of all leaves. This physically removes large numbers of mites and webbing before treatment and makes subsequent sprays significantly more effective. Wipe any stubborn webbing off with a damp cloth or cotton ball.
Treatment: What Works Against Spider Mites
The most widely available and effective treatments for spider mites on houseplants are neem oil, insecticidal soap, and, for more serious infestations, dedicated miticides. Each works by disrupting the mite's physiology on contact.
Neem oil: A natural plant-derived oil that disrupts spider mite feeding and reproduction. Mix to the directions (typically 5 ml neem oil, 2 to 3ml of dish soap as an emulsifier, per litre of water) and spray thoroughly on all surfaces including undersides of every leaf, stem junctions, and the growing tip. Apply in the evening to avoid any interaction with bright light. Neem oil has a residual effect of several days and acts on eggs as well as adults.
Insecticidal soap: Disrupts cell membrane function in mites on contact. Very effective when applied thoroughly and repeatedly. No residual effect, only kills mites it directly contacts, which is why repeated application is essential to catch hatchlings.
Apply either treatment every five to seven days for at least three to four cycles. Do not stop after one treatment, even if the plant looks clear, mite eggs hatch within a few days and a new population will re-establish quickly from unhatched eggs.
Environmental Prevention
Spider mites thrive in hot, dry conditions, exactly the environment created by central heating in UK homes in winter. Increasing humidity around plants is one of the most effective preventive measures. Group plants together, use a pebble tray with water (see our guide to houseplant humidity), or run a humidifier in the room. Mites struggle to establish on plants with moist leaf surfaces.
Regularly wiping down leaves with a damp cloth removes potential food sources and early-stage mite populations before they establish. This is particularly useful as a routine for susceptible species like Calathea and Alocasia.
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