If you haven’t already done so, you are probably making plans to move potted plants from outside to inside for the winter. Those plants have been enjoying the summer on your deck or porch and you probably haven’t paid a whole lot of attention to them. Now is the time to do a pest check on any plants that are going to make the seasonal transition.

Potted plants can be harboring pests either on the leaves and stems (aphids, spider mites, whiteflies, scale, mealybugs), or in the soil (fungus gnats, earthworms, slugs, earwigs, ants, sowbugs). The amount of pests or pest evidence that you find will determine how you treat that plant.

Houseplant Triage Procedure

• Check each plant and pot for signs of pests or pest damage like chewed leaves, sticky leaves, webbing, eggs, and stippling of leaves. Make sure you check the undersides of the leaves especially (see Pests on Your House Plants).

• Some larger foliage pests such as spiders, crickets, caterpillars, sowbugs, even aphids, can be picked off or sprayed off with water.

• A good way to check for soil pests is to soak the pot in lukewarm water for 15 minutes. This will force soil-dwelling insects to the surface. If you have a lot of pests in the pot or you find that the pot is harboring an entire ant colony, you may need to repot the plant with fresh soil.

• If the foliage of the plant is infested, plan to spray the plant with an insecticide a few days before you bring it inside. Check for products that are labeled specifically for use on indoor houseplants. Insecticidal soaps are usually a good choice.

• If you have the space, quarantine the plants that you bring in from outside. Until you know that the pots are pest-free (about 6 weeks), isolate them in a separate room, or at least a separate area, from other indoor plants.

• If the plant is too heavily infested with pests, toss it. Don’t risk bringing it indoors to infest your other plants. The transition to warmer, dryer indoor air is stressful for a plant so chances are a sick plant wouldn’t make it anyway.