Wise to bring tropical plants indoors gradually
Q: How do I ensure I do not bring any unwanted guests into the house when it is time for our tropicals to come back inside?
A: Because most houseplants are actually tropical plants, many of us bring our tropicals outdoors in the summer months to enjoy the fresh air, sunshine and refreshing rains. But as the days grow shorter and the night temperatures start dipping into the 50s consistently, it is time to prepare our plants for their journey back inside for the winter. It is wise to do this in stages.
As you begin the process to acclimate your plants to the light and humidity changes from outside to indoors, you will also want to thoroughly inspect your plants for unwanted guests. Small insects such as mealy bugs, spider mites, scale, white fly and aphids can hitchhike a ride into your home for the winter and infest the rest of your indoor collection.
Start with a good cleaning and pruning. I like to do this following a nice rain. Hose off your plants top to bottom, paying special attention to the undersides of the leaves. You may wish to wrap a plastic sheet around the base of the plant to cover the pot and conserve the soil. Remove all damaged foliage and prune judiciously; many plants grow considerably larger during their summer sojourn. Determine whether you need to repot your tropical or prune it back. If you are pruning, limit yourself to reducing the plant by no more than a third of its size and remember to prune the roots as well. If repotting, be sure to use a container that is no more than 2 inches larger than its current container and use fresh potting mix intended for indoor plants.
Now move the plants to a protected area such as a covered porch or along a north wall and give them a few days to rest. During this time, keep an eye on your tropicals; look for trouble signs and take action on any insects you find.
Mealy bugs are indicated if you see cotton-like clumps on the stems and leaves. There may also be a sticky substance on the leaves called honeydew that could attract ants or lead to the growth of sooty mold. Isolate the plant and try dabbing each mealy bug, which look like flat oval soft spots or fuzz on the leaves, with a cotton swab dipped in rubbing alcohol. Then rinse with clean water.
Spider mites are hard to see given their diminutive size but they leave telltale webs at the leaf axils and you may notice small yellow or brown spots on the leaves. To confirm their presence, try holding a sheet of paper below the plants and gently shake it. If pepper-like specks appear on the paper, it is likely spider mites. A good shower including the undersides of the leaves is in order and may be needed weekly for a month or so to keep the mites at bay. I have found these little buggers are quite persistent and will keep returning all winter so it may be best to dispose of the plant.
Scale looks like little green or tan flat ovals usually lined up along the main vein on the underside of the leaves. You may notice yellowing leaves or the sticky honeydew, which in turn leads to the growth of sooty mold. Isolate the plant and try gently scraping the scale off with your fingernail or a soft toothbrush. Or dab with an alcohol-dipped cotton swab. Give it a good shower and keep a close eye on it. Repeat as needed or dispose of the plant.
Whiteflies reveal themselves as a cloud of white specks that arise whenever the plant is jostled. The nymphs may drop their honeydew, which in turn attracts ants or leads to the growth of sooty mold. These are best controlled with an insecticide labeled for the use in controlling white flies such as neem oil foliar spray, which is considered a safe, nontoxic insecticide that works as a systemic in many plants.
Aphids are small insects that cluster on the undersides of leaves and tender stems, resulting in yellowing, distorted leaves and leaving the unsightly black sooty mold forming on their honeydew. A good spray with the hose can take care of most aphid problems. Severe infestations may require an insecticide.
After this adjustment period in the sheltered outdoors, gradually bring your plants indoors in small groups. Keep them isolated for a few more days before allowing them to join your other indoor plants. I put my plants on the kitchen table by a sunny window for a few days so I can keep a close eye on them. With the kitchen sink close by, I can continue to spray them as needed for both increased humidity and pest control. This final quarantine period gives you one more chance to stop any unwelcome pests from entering in your home while gradually adjusting you tropicals to their dryer, indoor winter habitat.
- Stephanie Kenn
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