What do spider mites look like?

Almost invisible — under a tenth of a millimetre, appearing as moving dots on a leaf underside. The damage is more visible than the mite: a fine pale stippling across the leaf, as though it has been dusted with sand.

Does spraying water get rid of spider mites?

It helps considerably and does not finish the job. Mites hate humidity and a forceful spray dislodges many of them, but eggs survive it, so a single rinse buys a week rather than solving anything.

Fine Webbing and Speckled Leaves

By IdentifyThese Editorial · Reviewed October 2026 · 3 min read

Spider mites are not insects and do not respond to most insecticides, which is the first reason infestations run so long.

The early sign

Not webbing. Fine pale dots across the leaf, densest near the midrib, giving a stippled or dusty look.

Each dot is a cell the mite has emptied. From a distance the leaf looks faded or dirty rather than damaged, and it is routinely attributed to dust, hard water or age until the plant starts declining.

Hold a suspect leaf up to a window. The stippling reads clearly against the light, and it does not wipe off.

Confirming it

Tap a leaf firmly over a sheet of white paper. Mites fall off and walk, and moving specks on white paper are unmistakable even when they are too small to resolve properly.

Or use a phone camera at maximum zoom on the leaf underside. It is not a good microscope and it is enough to show legs.

Stage	What you see	How long
Early	Faint stippling, no webbing	Often weeks, missed
Established	Leaves greying, stippling dense	Days to a week
Advanced	Fine webbing on tips and undersides	Population very large
Terminal	Webbing over whole growing points	Plant usually lost

Webbing is a late sign. A plant showing it has been infested for some time and holds an enormous number of mites.

Conditions

Hot, dry and still. Indoor plants near a radiator in winter and greenhouse plants in a heatwave are the classic cases, and the same plant outdoors in humid weather rarely has a problem.

That is exploitable. Raising humidity and moving air across the plant slows reproduction substantially, and it is the one control measure that does not need repeating every week.

Treatment that works

Rinse first. A forceful spray, leaf undersides included, in a shower or with a hose. This removes most of the adults mechanically and costs nothing.

Then treat, repeatedly. Insecticidal soap or horticultural oil, every five days for three weeks. The interval matters: eggs hatch in about three days in warm conditions, and a weekly schedule lets a generation through.

Isolate. Mites move between touching plants and travel on hands and clothing.

Raise the humidity. Grouping plants, a tray of pebbles and water, or a humidifier all reduce the rate at which the population rebuilds.

What does not work

Household insecticides aimed at insects, since mites are arachnids and many products simply do not affect them.

A single treatment of anything. This is the failure mode that defines the pest: the plant looks clear, treatment stops, and the population is back within a fortnight.

Neem oil applied once and hopefully. It works as part of a repeated programme and does very little as a one-off.

When a plant is beyond it

Heavy webbing over the growing tips on a plant that has lost most of its leaves is usually the end. Mites will have spread to whatever is nearby, and treating the survivor while it acts as a reservoir helps nothing.

Removing that plant and treating the neighbours is frequently the better call, and it is worth making early — the same reasoning as when not to spray, where the question is what the intervention is actually going to achieve.

Checking new arrivals

Most infestations arrive on a new plant. A fortnight of isolation and a look at the leaf undersides before it joins the collection prevents the great majority of them, and costs nothing but shelf space.

Problems referenced

Spider MitesAct now

Check these two things first

Push a finger into the soil, two knuckles deep. Wet soil plus a wilting plant means too much water, not too little — and it is the commonest reason a plant is dying. Dry soil plus crisp leaves means the opposite. The leaves look nearly identical either way, so the soil is what tells you.
Turn a damaged leaf over. Half of all diagnoses live on the underside: fuzz means downy mildew, fine webbing means spider mites, clusters of insects mean aphids. Nothing on the top of a leaf is as informative.

Most garden problems are cosmetic and resolve without treatment. Reach for a spray last, not first.