Gardening With Allen: Help indoor plants see the light

Now that I’m inside more and paying more attention to my indoor plants, I’m noticing that older leaves on some plants are turning yellow and falling off as fast as new ones are produced. Their general color seems to be dull. What can I do to perk them up?

Plants use light energy to create new growth. We are going into the lowest light conditions of the year. Days are getting shorter and light intensity is diminishing as well. As long as plants are producing new leaves, there is not a lot to worry about. A few things help, however.

Make sure plants get the best light available. Plants that are away from windows can be moved closer. South-facing windows get the most light. Make sure curtains and shades are completely open during daylight hours. Table and reading lamps make good supplemental light when the light source is close to plant leaves. Lights near plants can be left on even when there is no one in the room.

Plants accumulate dust on their leaves that filters out light. Shiny leaf plants can be washed with water or leaf shine. Fuzzy leaf plants do not like water on their leaves, so a feather duster or similar tool should be used.

Avoid overwatering and overfertilization. Our tendency is to water plants on a regular schedule, such as once a week. Slower plant growth means less water and fertilizer are used by the roots. When soil stays too wet, oxygen is more limited for the roots, which limits root growth. Check to make sure the soil is dry on top before watering.

It does sound like the plants with older leaves turning yellow and falling off may need additional fertilizer. When plants do not have adequate nitrogen to support new growth, they transfer it from older leaves to new growth.

If you use soluble or liquid fertilizer, apply it at half the recommended rate. I like timed-release fertilizers like Osmocote. Their release is directly related to the water that is applied. The granules are covered with a porous material that allows water to seep in and dissolve a little fertilizer and then seep out. So the plants receive a little fertilizer every time they are watered.

You may want to consider adding or replacing some of your plants with those that need less light. Go online and search for “low light indoor plants.” Some of my favorites are cast-iron plant (Aspidistra), peace lily (Spathiphyllum), Chinese evergreen (Aglaonema) and snake plant (Sanseveria). Dracaena, dieffenbachia, parlor palm (Chamaedorea elegans) and devil’s ivy (pothos) are also tolerant of low light.

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