At Winding Pathways, we take joy in fall’s colorful leaves, cool days, and clear air, but we know insects are on the move.

Box Elder Bugs, Asian Beetles, other insects and spiders, and mice all sense that frigid air is on the way and seek shelter from the cold. Houses offer secure nooks and crannies to hide in and central heat to keep them toasty warm. Houses also imitate natural wintering places. Asian beetles, for example, naturally winter in the cracks of rock outcroppings. So, a house makes a perfect substitute.

Caulking Tool

Filling a Crack

Homeowners have options for reducing winter insect infestations. Many turn to insecticides when they spot beetles or bugs clustering on interior windows and walls.   We avoid poison and opt for nontoxic solutions.

At Winding Pathways, we simply make it hard for bugs and mice to enter.  We can’t keep all of them out but we greatly reduce their numbers.  Here’s what we do before the first frost:


  • Load a tube of exterior caulk into our caulking gun and inspect our house’s exterior. We squirt caulk into every crack and hole in the siding. Likely bug entry points are where wires, cables, and pipes enter the house and around door and window frames. Often old caulk has split or fallen out, so we replace it. We also inspect thresholds to make sure there is no space beneath doors for bugs to enter. Sometimes we need to replace weather stripping around doors and windows.
  • Keep most firewood outside. We used to bring several days’ worth of firewood inside to make feeding our woodstove convenient but insects, like mosquitoes, hitchhiked on the cordwood and then roamed around the house. We now keep the wood in the cold just outside the door and only bring in a few pieces at a time when we need to feed the fire.
  • There’s an added benefit to excluding insects and mice. The holes and cracks they use to squeeze into the house also invite in winter’s cold air. Sealing them up keeps the house warm and lets us use less fuel in our furnace and wood stove.
  • Cleanse houseplants. We move some houseplants outside for the summer and bring them back indoors before the first frost, but insects can ride the plants into our home.  To prevent this, we carefully clean and repot plants. Master Gardener, Tina Patterson, had an excellent column in The Gazette, Living Section, Sunday, October 1, 2017, that describes in detail ways to safely clean your plants and keep them healthy inside all winter. We have reprinted this with permission of the Gazette, Linn County Master Gardeners Program, and Tina Patterson.


Don’t bring in bugs with those summer plants, By Tina Patterson, Iowa State University Extension

Time to bring in those houseplants that have been soaking up the sun outside all summer. As temperatures drop, it is a good idea to make sure they make the trip alone. Bugs and spiders and even tree frogs have made their way into my house before I learned a couple of little tricks to keep them at bay. Trevor the tree frog hid in the soil of a lemon tree only to pop out one warm winter afternoon. Before you bring pots into your home, prep them for the trip. A large bucket of water with a mild soap without degreaser or detergent should do it. Trim off damaged leaves while inspecting for insect eggs on the undersides. Submerge the pot into the bucket and let it sit for 10 to 15 minutes. This should be long enough for any bugs lurking under the soil line to leave.

After removing, let it drain. Scrub the outside and bottom of the pot with a stiff brush to remove dirt and possible bugs. Rinse foliage that did not getsubmerged with a slow hose. Don’t be concerned about soil floating out of the pot. Just top it off with fresh soil once it has drained. Skim any leaves or soil that floats free. You can soak four to five pots in the same water before refreshing.

If you suspect insects deep in the soil or the plants are in need of a fresh pot, it might be a good idea to remove them from their pots, rinse the soil off the root system, let them soak for 10 to 15 minutes and repot in a fresh pot with fresh soil. Boston ferns are good candidates for this because their roots can benefit from a good long soak before coming indoors for the cold months.

Another method for dealing with potential insects is to give them a one-two punch by adding a systemic insecticide that may keep pests where they belong. Added to the soil and watered in, systemic pesticides are water soluble and are absorbed by the tissues of the plant to reach the leaves, flowers, fruit and roots. One fairly simple remedy is one part 3 percent hydrogen peroxide mixed with four parts water, which will drastically reduce gnats in your pots.

Physical traps can help to cut the insect population down to size. Yellow sticky traps or insect tapes are good for fungus gnats that live in the first inch of soil. Keep air moving on well-lit plant shelves. It will help keep mealy bugs and aphids away.

With a little prep work, your plants will be healthy and happy through the winter months – and relatively bug free.

For questions, call the Linn County Extension Master Gardener Hortline at (319) 447-0647.


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