Cold Weather Houseplant Care

        

As the weather turns cooler, we begin to pay more attention to horticultural chores in the great indoors. Houseplants need a bit of TLC right now, as they adjust to the change of seasons. Houseplants tend to slow down their growth cycles now, so their food and water requirements are less.

        Many houseplant aficionados won't even feed their houseplants now, and won't resume a monthly fertilization until next spring. And because houseplants use less water now, change your irrigation habits. 

     Poke your finger or a moisture meter into the soil of a houseplant to make sure that the top few inches have dried before you add water. Another way to determine if your houseplant is in need of water: lift the pot. If it is as heavy as it was when you last watered, wait. When the soil has dried, that pot will be a lot lighter, a good sign that it's time to pour it on.

        During fall and winter, the sun is lower in the horizon. Help your houseplants cope with this lower level of light by moving them a bit closer to a sunnier window.

        There are some indoor plant pests that may be moving into your house this time of year. Aphids, spider mites, whiteflies, fungus gnats and scale are among the pests that are taking up residence with you, especially if your houseplants have spent any time recently outdoors or are new purchases. A couple of good books about houseplants, including lots of pictures of plants and pests, are "The Complete Houseplant Survival Manual" by Barbara Pleasant and "Successful Houseplants" by Ortho Books.

        And one reader is wondering about how to control another common houseplant pest. From the garden e-mail bag, Cynthia writes: "I have an indoor coleus plant in my bathroom, which gets indirect sunlight. All was well until yesterday when I discovered little oblong or rectangular-shaped, white, fluffy somethings on the plant. What are they and how do I eradicate them?"
        

     Those "fluffy somethings" might be mealybugs. These soft-bodied sucking insects are about one-eighth of an inch long, and are covered with a whitish, cottony wax. They especially like to congregate on the backsides of the leaves of houseplants, where the leaves meet the stems.

        There are several steps you can take to control mealybug populations on your houseplants. Step One: wash off the plant, especially the underside of the leaves, in the sink with a forceful stream of lukewarm water. Doing this once or twice a week for a few weeks may take care of the problem. Step Two: Dip a cotton swab in rubbing alcohol and remove the mealybugs by hand. Tweezers can help dislodge the ones you can't reach  with a cotton swab. If those two techniques don't do the job, apply insecticidal soap or a narrow-range horticultural oil to the infested plant area. But be careful: make sure your plant won't be damaged by the soap or the oil by testing it on a small, out-of-the-way part of the plant first. According to Lori Ann Asmus of Emerald City Interior Landscape Services in Sacramento, scrape away and replace the top inch of soil in the potted plant. That can help eliminate future mealybug populations.