How to Check Plants for Pests Before Bringing Them Indoors
Hose, inspect leaf undersides, and quarantine outdoor plants before they join houseplants. Catch aphids, mites, and whiteflies at the door.
Published by ThriveThyme
pests houseplants overwinter indoors quarantine
How to Check Plants for Pests Before Bringing Them Indoors
Outdoor plants often carry aphids, spider mites, whiteflies, or fungus gnats. Bring those indoors and they can spread to clean houseplants fast. Hose the plant, inspect it in good light, and quarantine it for about a week before it joins your indoor collection.
This step belongs on the Overwinter Indoors checklist alongside pot-up and windowsill care.
What to Look For
| Pest | Where to look | Clues |
|---|---|---|
| Aphids | Soft new growth, stems, leaf undersides | Clusters of soft insects, sticky honeydew |
| Spider mites | Leaf undersides, especially in dry heat | Fine webbing, stippled pale leaves |
| Whiteflies | Leaf undersides | Tiny white moths when you disturb the plant |
| Fungus gnats | Soil surface and when you water | Small flying insects rising from wet mix |
| Scale | Woody stems | Brown bumps that scrape off |
Extension indoor-plant pest sheets stress inspection of leaf undersides and isolation of new plants. Do not rely on a quick glance at the top of the canopy.
Cleaning Steps
- Work outdoors or in a garage you can rinse. Lay a tarp if you need to catch soil.
- Spray leaves and stems with a strong stream of water. Support soft tips with your hand so you do not break them.
- Wipe large leaves with a damp cloth. Check leaf axils and the crown.
- Scrape or lift the top half inch of potting mix if you see algae, crust, or many gnats. Replace with fresh mix.
- For light aphid pressure, a mild insecticidal soap labeled for the plant can help. Follow the label. Do not mix random household cleaners.
- Discard plants that are heavily infested. One bad plant is not worth a houseplant outbreak.
Quarantine
- Keep the new plant away from other indoor plants for about seven days.
- Check it daily. Catch mites and aphids early while numbers are still low.
- Water carefully. Overwet mix favors fungus gnats.
- Only then move it next to rosemary, basil, or other overwintered herbs.
After Quarantine
Place the plant in the brightest suitable window and follow crop-specific care. Herbs differ: see windowsill care for herbs you brought indoors. Use the Houseplants light and water tool for check ranges, and how often to water houseplants for the finger test.
Next Steps
- Run the full bring-in list on Overwinter Indoors.
- Time the move with first frost date.
- For rosemary and basil specifics, open how to bring rosemary indoors for winter and when to bring basil and tender herbs indoors.