University of Illinois Extension

Bringing Plants Inside

Plants that were taken outside this past spring need to be prepared for coming back inside.

James Schuster

"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," explained Schuster. "Proper preparation should take at least two weeks to minimize foliage defoliation. Plants should first be checked for any insect damage and actual insects including their eggs."

Check closely the undersides of the leaves as well as where the leaf petioles attach to the stem. Using a Q-tip and alcohol, remove any insects and eggs. In some cases, an insecticide may be necessary. An organic pesticide such as insecticidal soap may help.

"This insecticide must come in contact with the insect to kill it since there is no residual activities for prolonged control," he said. "Therefore many repeat applications may be necessary. But be careful - this product may injure some plants especially succulents and cacti when used as a soil drench for mealy bugs."

Many times insects or their eggs are 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 and to meet the need to treat less often an inorganic insecticide may be more appropriate.

"No matter whether the product is an organic or inorganic insecticide - always follow all label directions and precautions," said Schuster. "You can consider removing the old soil, rinsing the roots and repotting with fresh soil when the plant is finally brought into the house. This can be done instead of using an insecticide. Insecticide use and repotting can cause serious stress to the plant. Which method is best depends on the plant and your "green thumb" ability. "

Diseases are a little more difficult to control. There are no curative fungicides for most diseases. The diseases need to be prevented. Powdery mildew can be a serious indoor disease when brought in on the plants you had outside. Often it shows up as severe defoliation weeks after the plant was brought in. You may or may not see a white powdery growth on the foliage. Use a fungicide starting several weeks before the plant is brought in. No fungicide should be used indoors on plants.

"Plants need to be slowly reconditioned to indoor growing conditions," he said. "Start by bringing into the house for an hour or two and then putting it back outside. Each day add several more hours to the inside time.

"While doing this keep the plants away from plants that have been inside all summer just in case your insect and disease controls fail. By the time two to three weeks have passed, the plant should be able to stay inside. Do not wait for frost to start preparing your plants for indoor life."