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Over the Garden Fence

Houseplants should be heading back inside

Late summer triggers a column on our houseplants that are going to be brought back into our homes for the winter. For many, we take them outside to let Mother Nature nurture them back to a better state of health, or to kind of take a vacation from having to care for them as carefully as we had been during the winter. You may have set them out on the ground under shrubs or evergreens, put them on the edge of the patio, or maybe you have plant stands you use under your trees in the yard.

No matter where they “summered,” there is a process to bringing them back inside. Since houseplants are not cold-tolerant, the best practice is to get them acclimated to being indoors long before we have cool and frosty temperatures, and long before the home furnace is running. Recent evenings in the 60s, and even the 50s, is a good clue to get that project started. Aim to be done by end of September.

Houseplants should be looked at carefully to see if you really want to bring them all back inside the home. Some have grown too big over the summer for the spot you have. Others may not have bounced back as you hoped. Once you know which ones are headed back indoors, cleaning them up is in order and that includes removal of any dead foliage, picking the outdoor litter out that accumulates during the summer, and probably a little trimming to make them more uniform.

The next step is very important; carefully inspect them for insects. They have been outside, so they have been host to a variety of outdoor insects, sow bugs, spiders, and earwigs to name a few. A strong stream of water to both the top and lower leaf surfaces will take care of the bigger ones. Flushing the pot with lots of water will drive the soil insects out. If you find spider mites or scale on any of the plants, a treatment with insecticidal soap or synthetic insecticide is needed with two or three repeated treatments to be sure the life cycle is broken. This is much easier to do while outdoors in the open than dealing with mites or scale insects in the home later. Consider heavily infested houseplants as a candidate for the compost bin. Same goes for any that did not make the list to return inside.

Houseplants in the full sun should be moved now to a shady spot to start the acclimation process to lower light levels along with extended watering intervals. The goal should be to bring in the plants before the furnace kicks on. Bring them in on the dry side and begin to water them carefully as the need for water will be less as they adjust to the lower light levels. Do not be surprised to see some leaves yellow and fall too as the change occurs. Learn more about houseplant care in an upcoming webinar.

About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.