How to Debug Plants Before Bringing Them Indoors for Winter

When warm weather comes around, it’s a great idea to bring your sun-loving houseplants outside to your yard, deck, or balcony to catch some extra rays. Once temperatures cool and days shorten, however, you’ll want to bring your plants inside.

But this process isn't as simple as simply carrying your plants back indoors. You’ll need to help them adjust to the lower-light indoor environment and make sure they’re not bringing any pests, diseases, dead growth, or unwanted dirt in with them. Here's how to get your plants bug-free and ready to come inside for the winter, including some tips from plant expert and lifestyle blogger Ren Lenhof.

• Working time: A few hours
• Total time: Several hours
• Skill level: Beginner

When to Debug Plants to Bring Indoors

If your region experiences temperatures below 50 degrees or so at night during winter, you’ll need to bring potted plants inside. Tropical plants can be damaged at temperatures as low as 45 or 50 degrees, and many succulents can’t survive below 40 degrees.

Before bringing plants back inside for the winter, clear space for them on window sills and counters. If necessary, purchase new plant stands, plant saucers, and maybe even a new floating shelf. If you have hanging baskets, add ceiling hooks or plant hangers as needed. It’s also a good idea to wash your windows inside and out so that you can maximize the light coming through during the winter months. 

It’s also best to start acclimating your plants to the lower-light conditions of your home before temperatures require you to bring them indoors. Two weeks before you estimate you’ll need to bring plants inside, begin moving them a little closer to your house each day, in spots with bright, indirect light rather than full sun. 

Tools and Supplies You Will Need

Before you begin, gather the following materials:

• Gardening gloves
• Fresh potting soil
• Pruning shears
• Rubbing alcohol
• Cotton swabs or balls
• Mild soap like Dr. Bronner's
• Large bucket or tub
• Scrub brush
• Small strainer with handle

Before Getting Started

When you’re finally ready to bring your plants inside, plan to spend an afternoon (or a day, depending on how many plants you have) getting them ready. Identify any plants that need to be repotted. Cut back up to a third of root growth before repotting them with fresh soil.

"I like 80 percent soil and 20 percent perlite for my plants," Lenhof suggests.

Use clean, sharp pruning shears to cut back any dead or damaged growth. You can also cut back up to a third of the plant if it has become overgrown during the summer.

"For your larger plants— such as palms or ficus, you can clip away any dead or dying branches and leaves, pull out any dead fallen leaves and branches from inside the planter," Lenhof says.

Step 1: Remove Insects From Soil

Before debugging the aerial portion of your plant, push out any insects that may have burrowed into the soil. Take note that this method only works with plant containers that have drainage holes.

Step 2: Soak Your Plants in Water

Fill a tub or bucket large enough to submerge your plant’s container with tepid water. Soak the container in the water for around 15 minutes to push any pests out of the soil. Skim the debris and any insects floating on the surface of the water with the strainer and discard. Remove the pot from the bucket and allow it to drain for an hour. 

Step 3: Inspect Each Plant

While the soil drains, inspect the leaves and stems of each plant for insects like scale, aphids, spider mites, or mealybugs. Aphids, which are tiny, light-green bugs, can be washed off with a mix of mild liquid soap and water; the soap will kill the aphids on contact. Use a cotton ball or swab dipped in rubbing alcohol to wipe away scale (brown, flat ovals on leaves and stems) and mealybugs. 

Step 4: Check for Spider Mites

Tiny spider mites often form webs on the undersides of leaves, but are so small they may be difficult to see. Look for light brown feeding spots on plants as a sign of spider mites. Spray leaves with a hose to remove spider mites, then treat the plant with insecticidal soap to remove any remaining mites. 

Step 5: Spray Plants With a DIY Solution (Optional)

For a more natural debugging option, "There are countless recipes online for homemade bug repellents and insecticides, but my favorite recipe is equal parts water and witch hazel, and around 20 to 30 drops of eucalyptus oil," Lenhof recommends. "Put the solution in a spray bottle and gently mist the leaves and soil of each infected plant. I like to spray my plants every other day until the bugs have been gone for around a week. If the number of bugs doesn’t seem to be going down, start spraying your plants once a day.

Step 6: Cut Away the Infested Part (Optional)

Keep in mind that it may be best to cut off a particularly infested portion of the plant—but avoid removing more than a third of its growth. If an infestation is extreme or you can’t remove all the insects from the plant with these methods, it’s best to throw the plant away and purchase a new one rather than risk bringing pests inside to infest your other houseplants.

Step 7: Clean Your Pots

After debugging your plants, give the outside of your pots a good scrubbing with a brush and soapy water. Rinse the containers off and let them dry outdoors, then bring them inside. To start, keep them in the sunniest window in your home before gradually moving them to their usual indoor spot over the next few weeks to help them acclimate to the lower light conditions indoors. 

Step 8: Continue Care As Usual

Care for your houseplants as usual, keeping in mind that with less light and cooler temperatures in winter, your plants may need to be watered a little less frequently. Keep an eye on soil moisture, and monitor the leaves and stems for signs of pests. If pests return, treat as described above to remove them.