Wednesday, December 2, 2020
Dec. 2, 2020

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Gardening with Allen: Artificial lights can help keep house plants green in winter

The Columbian

Most of my indoor plants do not thrive during the winter. Their color is lighter and duller and they lose a lot of leaves. Are there some things I can do now to keep them healthy and attractive during the next few months?

The main reason your plants do not grow as well during winter is the reduced natural light. Day length is much shorter and the angle of the sun is much lower. The combination reduces the amount of sunlight energy by at least 70 to 80 percent. In addition, many homeowners keep window coverings closed to reduce heating cost. Plants compensate for this lower light condition by growing more slowly and shedding older, less efficient leaves. Plants also produce fewer new leaves.

Two ways to increase the amount of light plants receive is to move them closer to windows (with curtains open) and give them additional artificial light. Even low-light tolerant plants can be placed right next to windows during winter months. Another approach is to replace high-light requiring plants with low-light ones.

A simple way to increase artificial light is to place plants near lamps and other light fixtures and leave them on during hours of darkness. Higher wattage bulbs can be used to increase the amount of light.

Special plant lighting fixtures can also be purchased with reflectors to direct the light down. Special bulbs are also available that increase the amount of light. For more information search online for “indoor plant lights.”

Indoor plants continue to need fertilizer during the winter. If you are using a liquid fertilizer every time you water, keep using it at the same rate. Your reduced frequency of watering will reduce fertilizer the right amount. I like to use slow-release coated fertilizer such as Osmocote for container plants. The amount of fertilizer released is directly proportional to the watering frequency. If you are using slow release fertilizer and have not applied any for awhile, make another application. The iron and nitrogen in the fertilizer will help keep plants a darker green.

The following low-light tolerant plants should be the bulk of the plants used in most homes without artificial plant lights: pothos or devil’s ivy (Scindapsus), snake plant (Sanseveria), dracaena, cast iron plant (Aspidistra), peace lily (Spathiphyllum), Chinese evergreen (Aglaonema), Rochford holly fern (Cyrtomium), dieffenbachia, parlor palm (Chamaedorea) and Kentia palm (Howea).

Allen Wilson is a Vancouver gardening specialist.