Volume 14, Issue 39 ~ September 28 - October 4, 2006

The Bay Gardener

By Dr. Frank Gouin

Make Room for Houseplants

Help your potted garden make a smooth transition indoors

If you’ve moved your houseplants outdoors during the summer months, the time’s ripe to carry them in.

July and August’s drought increased populations of white flies, aphids and spider mites. Outdoor houseplants most likely attracted some of those pests this summer. That means before plants make the move indoors, start controlling these insects now.

Group plants together and spray thoroughly with insecticidal soap, according to manufacturers directions. Insecticidal soaps only kill adult insects and do not suffocate the eggs. Repeat weekly for at least three weeks.

If you notice that your plants have small tiny webs stretched between leaves, leaves and stems or between petals of flowers, spider mites are most likely the culprits. Control a spider mite infestation by spraying them with horticultural oil (also known as summer oil). Horticultural oil will curb both adult spider mites and eggs with a single application. As a precaution, however, you should spray the spider mite-infested plants now, and again a day or two before they make the move to your living room. As an added bonus to controlling the spider mites, the horticultural oil will make house plants’ foliage glossy.

If houseplants enjoyed full sun outdoors, you’ll need to condition them for growing indoors, where the sunlight is much less intense. Moving a plant from full sun into partial shade or full shade will cause leaves to wither. To condition the foliage to a lower light intensity, move the plant from full sun into a light shade and allow the plant to acclimate for at least three weeks. After its first three weeks are up, move the plants into more intense shade for an additional three weeks before bringing the plant inside. Start now, and you can combine insect control with plant conditioning.

Check up on houseplants that have been growing in the same container for a year or more by removing the plant from its container and examining the roots. If the roots completely cover the outside of the root ball, the plant is root bound and should be repotted. Learn the proper way to repot houseplants in next week’s Bay Gardener.

Ask Dr. Gouin your questions at frgouin@erols.com. All questions will appear in Bay Weekly. Please include your name and address.

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