A drop in temperatures means it’s time to prepare potted plants to head indoors for the winter, but your leaved lovelies will need more than a simple change of scenery to survive the cold season.
“If plants are brought in without any re-adaptation, the leaves will yellow and fall off just like they did when the plants were taken outside in the spring without proper hardening off,” says James Schuster, a plant pathology specialist at the University of Illinois Extension. “Proper preparation will take at least two weeks to minimize foliage defoliation.”
First, check your plants for insect damage, actual insects and insect eggs. Examine the undersides of the leaves as well as where the leaf petioles attach to the stem. Using a cotton swab and rubbing alcohol, remove any insects and eggs. In some cases, an insecticide or organic pesticide may be necessary.
“This insecticide must come in contact with the insect to kill it since there are no residual activities for prolonged control,” Schuster says. “Therefore many repeat applications may be necessary.”
Insects and their eggs are often in the soil. On very porous soils, more mealy bugs will feed on plant roots than on the upper part of the plant. For longer control, an inorganic insecticide may be more appropriate.
“Follow all label directions and precautions on both organic and inorganic insecticides,” Schuster says. “Instead of using an insecticide, you can remove old soil, rinse the roots, and repot the plant with fresh soil when it is finally brought into the house. However, both insecticide use and repotting can cause serious stress to the plant.”
Diseases are a little more difficult to control as there are no curative fungicides for most plant diseases. Therefore, diseases need to be prevented.
Powdery mildew can be a serious indoor disease on plants kept outside, often causing severe defoliation weeks after the plant is brought indoors. You may or may not see a white powdery growth on the foliage. Begin to use a fungicide several weeks before the plant is brought inside, but do not use it once plants are indoors.
Introduce Plants to Indoors
“Plants need to be slowly reconditioned to indoor growing conditions,” Schuster says. “Start by bringing the plant into the house for an hour or two and then putting it back outside. Each day add several more hours to its inside time.”
Keep your outdoor plants away from plants that have remained inside throughout the summer to prevent the spread of insects and disease.
“After two or three weeks, the plant should be ready to stay inside. Do not wait for frost to start preparing your plants for indoor life,” Shuster says.