Those “little white flies flying around” are most likely whiteflies or a similar tiny sap‑sucking insect that swarms when plants are disturbed.

What they probably are

  • Whiteflies are tiny, moth‑like insects (about 1–2 mm long) with white, powdery wings that fly up in a little cloud when you brush past infested plants.
  • They are closely related to aphids and mealybugs and live on the undersides of leaves , especially on houseplants, greenhouse plants, or outdoor ornamentals and vegetables in warm weather.
  • In some online forum posts, people describing “tiny white flies that look like ash” in the UK were also told they were likely glasshouse/greenhouse whiteflies.

If your “white flies” are mostly around plants, especially when you touch them, whiteflies are a strong candidate.

Why they’re there

  • Whiteflies feed by sucking sap from leaves, which can weaken plants and cause yellowing, stunting, and leaf drop.
  • They reproduce fast in warm conditions (indoors, greenhouses, or warm outdoor spells), so a small problem can turn into a visible swarm quickly.
  • They excrete a sticky substance called honeydew , which can lead to black sooty mold on leaves; this mold looks ugly but mainly grows on the honeydew, not in the leaf tissue itself.

Should you worry?

  • For people, they are generally more of a nuisance than a health threat ; the main risk is to your plants.
  • Heavy infestations can seriously weaken or even kill plants over time if not managed.

What you can do next

If this matches what you’re seeing, some common steps people use (and that gardening guides recommend) include:

  • Checking the undersides of leaves for clusters of tiny white insects and sticky residue.
  • Gently washing leaves with water or mild soapy water to knock numbers down (test a small leaf first).
  • Using yellow sticky traps near affected plants to catch adults.
  • Reducing overwatering and improving plant airflow, which can make conditions less favorable.

If your “white flies” are not near plants at all (for example, swarming indoors far from greenery or coming from drains), they could be a different insect, and sharing a photo with a local gardening group or pest‑ID forum is the quickest way to get a precise ID.