Gardening With Allen: Light is critical for indoor plants in winter

Most of my indoor plants are in the dumps. Leaf color is fading and leaves are dropping at an alarming rate. Is there anything I can do to perk them up?

The main problem with indoor plant deterioration this time of year is lack of light. Not only are the days short, but the sun’s rays come at a very low angle, which reduces light intensity to a fraction of summer time. We also have a lot of cloudy weather this time of year, which further reduces light energy.

Plants respond by reducing their growth rate and dropping older leaves that use more energy than they produce. Older leaves turn yellow because their nitrogen is transferred to new leaves. You can partially reduce old leaf drop by regular fertilization. Most liquid indoor plant fertilizers recommend application with every irrigation. If you used a timed-release fertilizer some time ago, it may have already been used up.

Over-watering can also cause plant deterioration. Make sure soil is dry on top before watering. When soil remains saturated with water, there is less room for air. Air contains the vital oxygen needed for root growth. If roots deteriorate due to lack of oxygen, they cannot support as many leaves.

The most important thing you can do is increase the amount of light that indoor plants receive. Move as many plants as possible close to windows. South-facing windows receive the most direct light. I place plants in a seldom-used room with a south-facing window. Make sure that curtains are open during daylight hours.

Artificial light can add to a plant’s needs, especially if the plant is close to the light source, such as under a table lamp. Sometimes a spotlight can be redirected to shine directly on plants. Lights placed for plant lighting can be left on at night so they receive additional hours of light energy.

Dust on plant leaves also reduces the amount of light that they receive. Leaves can be wiped with a cloth dipped in dish wash solution. Leaf shine products are available that clean leaves as well as adding shine. Fuzzy leaf plants such as African violet do not like to be wet. Test unfamiliar leaf cleaning and shining products on a few leaves before treating an entire plant.

Some indoor plants can survive at lower light levels. As you replace your indoor plants, select those that tolerate lower light conditions. Some of the best plants for low-light tolerance include: Spathiphyllum or Peace Lily, Aglaonema or Chinese Evergreen, Aspidistra or Cast Iron Plant, Epipremnum or Devil’s Ivy, Sanseveria or Snake Plant, and Dracaena. You can find additional choices in indoor-plant books or searce the internet for “low-light indoor plants.”

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