Released Oct. 23, 2007

UNIVERSITY PARK, Pa. - - The frigid face of winter is just around the corner, which means only one thing for your houseplants: The beach party is over. Unlike humans, houseplants can't survive the colder autumn nights in flip-flops and mini-skirts. Instead, they need to be prepped and brought inside to escape injury, says an expert in Penn State's College of Agricultural Sciences.

"We put the plants outdoors in the summertime because there is better light," says Jay Holcomb, professor of floriculture. "They get some wind and some rain; it is a much better environment to grow in. What we have to worry about is the first frost. Some tropical plants may even receive chilling injuries at around 40 degrees. Now that fall is here, think about moving your plants inside."

Holcomb says it will be necessary to prepare the plants for the move indoors. "The change from a high-light environment outdoors, to a low-light environment indoors will cause some of the older leaves to turn yellow and fall off," he explains. "In the fall, a little bit of trimming will help the plant adjust to low-level light environments, and by thinning out the center, your plant will be better off."

Holcomb recommends that you remove any dead foliage that has fallen inside the pot. "There could be more than dirt lurking under that dead foliage," he says. "You don't want to bring any unwanted pests into your home. It only takes one or two insects to start an infestation of your home," says Holcomb. "This is why houseplants brought in for the winter need to be checked for insects and other pests beforehand."

Some of the most common pests to look for include spider mites, mealybugs, aphids, white flies and scale. If your plant has yellow-speckled leaves and is covered with tent-like webs, it may mean your plant has spider mites. Though miniscule in size, these bugs can be very destructive. "Mites are similar in appearance to grains of cayenne pepper," says Holcomb. "Hold a piece of white paper under the plant and shake the leaves, and you will see the mites drop onto the paper."

If there are white, cotton-like masses where the leaves and branches attach to the stalks, then you have mealybugs. These tiny bugs nestle and lay eggs in these spots, stunting and killing plants by depleting their fluids.

Aphids are similar to mealybugs in size and also live in thick colonies along the soft parts of stems. The sweet liquid they excrete from their bodies, called honeydew, often attracts other unwanted guests into the home, such as ants. "Aphids are quite destructive," says Holcomb. "They cause distorted and curled leaves, malformed flowers and hardened buds."

If you shake the plant and notice small, white flies coming from the leaves, then your problem is white flies. The ability to take flight is what separates these insects from aphids and mealybugs. "You'll never find just one white fly on a plant," says Holcomb. "They come in quantities and can spread to all the plants in your house."

Scale appears as blister-like areas on stems and the undersides of leaves. These areas can be circular, oyster-shell-shaped or rectangular and are colored white, brown, gray or black. Scale also produces honeydew, which may drip from the leaves. Scale seriously stunts growth, says Holcomb; If not treated, it can kill the plant and spread to others.

If your plant shows signs of infestation by any of these pests, don't fear. You may not have to throw that plant away just yet. "If the infestation is small enough, then you may be able to wipe the pests off with a Q-Tip dipped in alcohol," says Holcomb. "Rinsing the plant under a gentle stream of water for a few minutes can wash away insects and eggs. Keep checking the plant for a recurring infestation during the next couple of weeks."

Another important step you can take is to dig around the roots and look for pests in the soil where insects such as sow bugs, millipedes and slugs reside. If there aren't many then they can be removed by hand. If there are too many, then you might want to try repotting the plant.

However, if your plant is not infested with pests, you can put off repotting the plant until the spring. "Don't repot in the fall unless it's necessary," says Holcomb. "In the spring, we are putting the plants into a good light environment, where they will get good root growth."

You also might want to start cutting down on plant fertilization during the fall. "Generally you fertilize in the summer so that it will not be necessary to do that when the plants are moved into the house in the fall," says Holcomb.

And if you think that having a plant outdoors is going to be too much of a hassle, then think again. "The advantages to having your plants outdoors are great," says Holcomb. "Sunlight, rain and warm weather produce a flush of healthy growth, and the pests are usually easy to get rid of. Overall, it's worth it."

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http://aginfo.psu.edu/News/07Oct/Houseplants.htm

Contact: Vincent Rome, (814) 863-0938