The Master Gardener Articles

---

What Are The Steps In Caring For Interior Foliage Plants
During The Winter?

Winter can be a tough time for interior foliage plants. From approximately October to April, most plants are in a non-growing state unless they are exposed to artificial light. Because they are not actively growing due to shorter day length, lower light levels, and cooler temperatures, care practices must be adjusted. Reduce watering, unless the home is very warm and humidity low; do not fertilize or repot plants; and increase light levels and humidity, if possible.

The ideal temperature range for most interior foliage plants is between 60 degrees F and 80 degrees F, while chilling injury can occur below 50 degrees F. Light exposure may affect temperature; typically, southern and western exposures are warm because of sunlight, while eastern and northern exposures are cool. Avoid locating plants on cold window sills, or where there are cold or warm drafts from opening doors and heating vents. Symptoms of cold damage to plants include leaf spots or blotches, downward curled foliage, slowed growth, and root rots. Excessively high temperatures cause yellowish-green foliage which may have brown, dry edges or tips, and spindly growth.

Tropical foliage plants thrive in their native environments where relative humidity is often 80% or greater, while humidity can drop as low as 20% in heated homes. Low humidity may cause brown or scorched leaf tips. Attempt to raise the humidity by grouping plants together, using a room or furnace humidifier, watering properly, and avoiding drafts and high temperatures. A pebble tray may also work - layer pebbles in a tray and fill with water just to the top of the pebbles. Set pots on the pebbles, just above water level. Misting foliage has not proven useful in raising humidity as water droplets evaporate rapidly.

Unless watering is adjusted in the winter months, plants can succumb to overwatering. Most plants are not actively growing and are using less water than they did during the growing season. Roots that are surrounded by water soon rot, eventually killing the plant. Unfortunately, the symptoms of overwatering and under watering are similar. Both lead to chronically poor root health, decline, and eventually death.

The best way to determine when a plant needs water is to feel the soil mix with a finger tip. If cool and barely moist to the touch, the plant is considered "moderately moist." If the soil mix is slightly moist, or questionable, it is best to wait another day or two and retest before watering. When watering, pour enough into the pot so that it drains out through the drainage hole. This method is also beneficial in leaching out excess fertilizer salts in the soil, which build up over time. It also exchanges the air in the soil mix. Do not allow drainage water to seep back into the soil mix; empty the saucer of excess water as soon as the container drains completely.

When watering, use water that is between 62 - 72 degrees F. Do not water plants with softened water which adds sodium and chloride to the soil mix and could cause plant damage.

The Master Gardener Offers horticulture advice and tips, focusing on current issues by volunteers who are with The Ohio State University Extension, Union County Master Gardener Program. For answers to gardening questions, call 937.644.8117 or e-mail gmcvey@ag.osu.edu. Hourse are 8 a.m. to 4:30 p.m. Monday through Friday