Match houseplant needs to their environment

Last Updated: 
December 4, 2009

houseplant photo by Tiffany Woods

CORVALLIS, Ore. – As hours of daylight grow fewer and early mornings become frosty, gardeners can turn their focus indoors to house plants that are sometimes neglected, or at least overlooked, during Oregon's outdoor summer dance.

The most important factor in the care of houseplants is to match their needs to their environment, and the most common mistake is to overwater, according to Ross Penhallegon, horticulturist with the Oregon State University Extension Service in Lane County.

Avoid placing plants near direct sources of hot or cold drafts, he recommends. A sudden change of temperature from doors, windows, furnace ducts, candles, wood stoves or television sets can hurt a plant. Wilting foliage and brown-tipped leaves could suggest a temperature problem.

To keep foliage green during the winter, fertilize lightly every other month, compared to every-month summer applications during the active growing season. Use a water-soluble medium-strength fertilizer (10-5-5) all times of the year for indoor plants.

Over-watering is the most common problem with houseplants, Penhallegon said. Water each plant according to its needs, he advises, rather than by a regular schedule. Plants in containers with drainage holes can be thoroughly watered because the excess drains out. Be aware that if you add too much water, the catch basin will overflow. If there are no drainage holes, before adding more water, stick your finger two inches into the soil to detect dampness. Water the plant only if the soil feels dry.

"Pots without drain holes often will cause lower leaves to yellow, and the plant will gradually decline; too much water encourages root rot," Penhallegon said. "Move plants to better-drained pots if you suspect inadequate drainage."

Insect pests can move in unexpectedly. Check the undersides of leaves regularly, especially on plants brought in from outdoors. Wash the foliage regularly with a mild soapy solution, taking care to rinse soap off completely. A fine water spray or wiping the leaves with alcohol-soaked cotton will take care of most insects. Rinse off all the alcohol.

Light source, light intensity, temperature and total room environment are all crucial to houseplants. Each plant has its own individual cultural requirements but will tolerate a few changes. Once a houseplant is happy and adapts, try not to move it much.

All plants require natural light. Generally, flowering plants prefer stronger light; foliage plants will tolerate very low light conditions. On the whole, it is best to avoid hot direct sun rays for long periods of time. A bleached out area on leaves indicates too much light. Thin, leggy growth means not enough light. Place plants near a south- or west-facing window to get a good indirect light source.

Author: Judy Scott