Spider mites are tiny arachnids, often yellowish-green or reddish, that live on the undersides of leaves, and the first signs are fine white stippling, a dull or faded look, and, later, fine webbing. Confirm them by tapping a leaf over a sheet of white paper and looking for specks that move. Then isolate the plant, rinse it thoroughly, and repeat. If washing is not enough, insecticidal soap or horticultural oil used exactly as the label directs is the next step, and extension guidance says to expect several weekly treatments, not one.
This guide explains how to be sure it is spider mites, what to do first, when soap or oil is worth using, and how to keep them from coming back.
What Spider Mites Look Like
Spider mites are arachnids, not insects, and they are very small. University of Minnesota Extension puts them at about 1/50 inch long, usually oval and yellowish or greenish, and says magnification is typically needed to see them. Clemson Extension describes them as looking like "little dots running around" to the naked eye, and notes that the common twospotted spider mite has two dark spots on its back.
The damage tells the story
- White stippling on the leaves: tiny pale dots where the mites have pierced and fed. Clemson names white stippling as the primary indicator.
- A faded, yellowish or greyish cast: the leaf loses its normal color as feeding continues.
- Yellow-green mottling that turns tan: Iowa State University Extension says damage progresses this way and can end in leaf drop.
- Fine webbing: Clemson notes that webbing appears when populations are high, and that heavily infested plants can be covered by a thin layer of it.
Confirm It First
Several things can stipple or fade a leaf, including sun scorch, dry air, and other pests, so check before you treat.
- Do the paper test. Clemson suggests tapping a leaf several times over a sheet of white paper, then looking at the paper for specks that crawl.
- Look at the undersides. Iowa State notes the mites live primarily on the undersides of leaves.
- Use magnification. Clemson recommends a 10X hand lens, and says even high-magnification reading glasses can help.
If the leaf tips are browning rather than stippling, you may be looking at a watering or humidity problem instead. Our guide to brown leaf tips goes through those.
Why They Show Up
Spider mites favor dry conditions. Iowa State says they prefer dry conditions, and Clemson notes that they do best in dry environments and that drought stress speeds up infestations. Heated, dry indoor air in fall and winter, plants parked near vents, and plants allowed to dry out repeatedly are the usual setups. They also arrive on new plants, so inspect anything new before it joins your collection.
What to Do, in Order
- Isolate the plant. Iowa State advises isolating infested plants so the pests do not spread to other houseplants.
- Rinse it thoroughly. Iowa State suggests rinsing the foliage well in a shower or outdoors. Clemson's houseplant guidance adds spraying sturdy plants forcefully with water, including the undersides of the leaves. Do not skip the undersides.
- Remove what is badly infested. Iowa State recommends removing leaves or branches that are heavily infested.
- Raise humidity a little. Clemson and Iowa State both note that higher humidity can reduce or slow spider mite populations. Our guide to increasing humidity for tropical houseplants compares the options.
- Rinse again, and keep checking. Iowa State advises scouting often and catching them early. One rinse rarely ends an infestation.
- If needed, use soap or horticultural oil exactly as labeled. Clemson suggests starting with insecticidal soap or horticultural oil, and notes that some plants are sensitive to soap. Its list includes ornamental ivy, maidenhair fern, dieffenbachia, schefflera, jade plant, and begonia. Clemson also says not to apply soap to plants under drought stress or in direct sunlight, and to check that the label allows the use you intend indoors. For temperature, Clemson says to avoid applying soaps and oils at 90°F or higher.
- Repeat. Iowa State says multiple applications every week for four to six weeks may be needed.
A Simple Weekly Routine While You Treat
It helps to turn the steps above into a routine so nothing gets skipped. On day one, isolate the plant, rinse it well, and remove badly affected leaves. Once a week, rinse again, including the undersides, and do the paper test to see whether anything is still moving. Apply soap or oil only if the label allows it and only as often as the label directs. When the paper test stays clean for several weeks and no new stippling appears, the plant can go back with the others, though it is worth continuing to check the undersides.
Common Mistakes
- Treating once and stopping. New mites keep hatching, so the cycle has to be interrupted repeatedly.
- Spraying only the tops of the leaves. The mites are on the undersides.
- Misting for humidity. Misting wets the leaf surface briefly but does not reliably change room humidity.
- Leaving the plant among others. Move it away before you start.
- Using a product the label does not allow. Clemson specifically warns to make sure the label covers indoor use.
What About Neem Oil and Home Remedies?
You will find many home remedies recommended online. The extension pages we reviewed for spider mites describe washing, humidity, insecticidal soap, and horticultural oil, and do not recommend home mixtures. We cannot vouch for them, so we have not built them into the steps above. If you try one, test it on a single leaf first and wait a few days to watch for damage before treating the whole plant.
Keeping Them Away
- Inspect new plants and keep them apart from your others for a couple of weeks. Our guide to what to do when your plant arrives in the mail walks through the first-week routine.
- If your plants spent the summer outside, rinse and inspect them before they come in. See our guide to when to bring houseplants inside.
- Keep plants away from heating vents, and do not let them dry out repeatedly.
- Check leaf undersides when you water.
From the Greenhouse Bench
Looking closely is most of the job. The white paper tap and a hand lens are standard scouting tools, and they cost almost nothing. Pests are easier to deal with in the first week than the fourth. If you also see small flying insects near the soil, that is a different problem: our guide to fungus gnats explains it.
Frequently Asked Questions
Are spider mites insects?
No. Iowa State describes them as arachnids, in the same group as spiders and ticks. They are not insects, though they are often treated as houseplant pests.
How do I know it is not just dust or dry leaves?
Do the paper test and check the undersides with magnification. Dust does not move, and stippling that is concentrated on the undersides of leaves and spreads over time points to mites.
Can spider mites spread to my other plants?
Yes. Iowa State advises isolating infested plants so the pests do not spread.
How long does it take to get rid of them?
Plan on weeks, not days. Iowa State notes that multiple applications every week for four to six weeks may be needed when using soap or oil.
Will humidity alone fix them?
It helps, but it is not enough on its own. Clemson and Iowa State say higher humidity can reduce or slow populations, which is why it is a supporting step alongside washing.
The Short Version
Confirm with a paper test, isolate, rinse hard and often, raise humidity, and use soap or oil only as the label directs. Repeat for weeks, then keep checking the undersides.
Sources: Clemson Cooperative Extension: Integrated Pest Management for Spider Mites, Clemson Cooperative Extension: Common Houseplant Insects and Related Pests, Iowa State University Extension: Diagnosing Houseplant Problems Caused by Insect Pests, and University of Minnesota Extension: Managing Insects on Indoor Plants. Always follow the label on any pesticide product.