Quick identification: the four usual suspects
| What you see | Likely culprit | Harmful? |
|---|---|---|
| White/grey specks that jump or hop when you water | Springtails | No — decomposers |
| Slow, round, dust-like white dots crawling on the soil surface | Soil mites | No — decomposers |
| Slightly fuzzy, oval white insects that also appear on stems and leaf joints | Mealybug crawlers | Yes — sap feeders |
| Translucent white worms with black heads in the top few cm of soil | Fungus gnat larvae | Yes — root feeders |
Springtails: the jumpers (harmless)
Springtails are tiny (1–2 mm) wingless arthropods that live in consistently moist potting mix and eat decaying organic matter, fungi and algae. Their signature move is the jump — disturb the soil or water the pot and they ping around like fleas. They do not feed on healthy plant tissue.
A big springtail population is really a moisture signal: your soil is staying wet longer than it should. Let the top few centimetres dry between waterings and numbers drop on their own. Chronically wet soil is also the fast lane to root rot, so this is worth fixing regardless of the bugs.
Soil mites: the slow crawlers (harmless)
Soil mites look like slow-moving specks of white or tan dust, usually less than 1 mm across. Like springtails, they’re decomposers — they break down dead roots, bark and compost, and they’re actually a sign of biologically active soil. No treatment needed. If they bother you, scrape off and replace the top 2–3 cm of potting mix and water less often.
Don’t confuse them with spider mites, which live on leaves (not soil), cause yellow stippling and spin fine webbing — that’s a real pest with its own playbook: spider mites on houseplants.
Mealybug crawlers: treat these
Mealybugs are sap-sucking insects. Adults are cottony white ovals, and the juvenile "crawlers" are smaller, mobile versions that can wander across the soil surface on their way to stems and leaf joints. Some species (root mealybugs) live entirely in the soil, coating roots in a white, waxy fuzz.
Fix: Dab visible mealybugs with a cotton swab dipped in 70% isopropyl alcohol, then spray the whole plant with insecticidal soap or neem oil, repeating weekly for 3–4 weeks to catch new crawlers. For root mealybugs, unpot the plant, rinse the roots clean, discard the old soil and repot in fresh mix. Isolate the plant from its neighbours until it’s clean.
Fungus gnat larvae: treat these too
If you also see small dark flies drifting around your plants, the white "bugs" in the soil are probably fungus gnat larvae — translucent, legless worms up to 6 mm long with shiny black heads, living in the top layer of moist soil. Larvae feed on fungi and fine root hairs, and heavy infestations stunt seedlings and stressed plants.
Fix: Let the top 3–5 cm of soil dry out (larvae need moisture), trap adults with yellow sticky cards, and drench the soil with a BTI product (Bacillus thuringiensis israelensis, sold as Mosquito Bits or similar) to kill larvae. Full walkthrough here: how to get rid of fungus gnats.
Can’t tell which bug you’ve got?
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Coming soon to Google Play →Prevention: keep the soil boring
- Water only when the top few centimetres of soil are dry — moisture is the invitation.
- Use pots with drainage and empty saucers after watering.
- Skip the "top layer of compost" habit indoors; decaying matter feeds decomposers and gnats.
- Quarantine new plants for two weeks and inspect the soil surface before mixing them in.
- Set watering reminders so pots never sit soggy between erratic waterings.
