Originally Published In The Deseret News -- Wednesday, January 13, 1993
The bright side of winter is that it diverts our attention from the outside garden to the interior garden. Indoor gardening is a fascinating and popular hob-by, and attracts more devotees each year. Soothing, decorative and fun aspects of indoor gardening help diminish the dreariness outdoors.
There are those who become totally frustrated with indoor gardening. One acquaintance of mine is totally convinced that life and garden abilities were never fair. She claims that although she did everything her neighbor did, plants just didn't like her and went to great lengths to avoid growing in her home. Her claim is that her thumb was so "black" that plants chose death rather than spend time in her care.
Leaving on a vacation, she left several of her houseplants that were in a declining state of health with a green-thumb neighbor. Her story, which she claims is true, is that upon her return home, she went to her neighbor's house and found the sickly, drab specimens she had left were flourishing under the neighbor's watchful eye. When she said, "These plants look so wonderful, I think I'll take them home right now," two of them jumped off the shelf, committing suicide rather than go back under her care.
Hopefully you haven't put any of your plants in such high-risk situations. Houseplants grow and flourish because they have the right growing conditions, and they decline and die if they don't have certain basic needs provided.
Lighting for plants is always a mystery to some. All plants that have chlorophyll and manufacture their own food require a certain amount of light to maintain themselves. To grow or do well, plants require even more light. Dull winter days when the sun rises late and sets early cut the amount of light tremendously. Plants that flourished during the summer now show lackluster performance because the amount of light is greatly diminished. As humans, our eyes adjust for changing light levels, so we do not notice the difference as the plant does. If there is insufficient light, plants simply do not grow.
If plants are not growing, that reduces the need for the two most commonly added growth factors. Water is essential for all plants. The water needs of a plant vary greatly, but under periods of low light intensity, water needs are greatly diminished. The best moisture meter you have is the end of your finger. For most indoor plants, stick your finger an inch or two into the soil. If the soil feels moist, leave the water can in the closet. If it is dry, add enough water to soak the soil and allow a slight amount to run out of the bottom. Any more keeps oxygen from getting to the roots and causes decay of the small feeder roots that are so vital for absorbing water and nutrients.
Fertilizer is another misunderstood growth factor. Cartoons often show bottles of fertilizer dumped on plants and the resulting instantaneous supergrowth. Fertilizers are nothing more than nutrients that plants utilize to manufacture their food. In and of themselves they are not plant food and cannot substitute for the plant manufacturing its own. Once again, in periods of low light intensity, the need for fertilizers is greatly reduced.
Applying fertilizers when the rest of the plant systems are functioning in an arrested state is a sure way to create problems. Use fertilizer sparingly, if at all, during the winter season on most plants. As plants start to grow and develop new leaves in the spring, add fertilizers, because the plants will then be able to use the nutrients. Fertilizers added when they are not needed contribute to salt build up in the soil, and if overused can cause the demise of the plant.
Environmental problems with light, temperature, water or nutrient extremes are the major causes of failures of plants. Occasionally pests do cause problems. Insects and mites attack many species of plants. Prevention helps alleviate serious problems. Give smaller plants a shower every few weeks to wash away unwanted pests. Turn the plants upside down and run tepid (90 degrees Fahrenheit) water on the underside of the leaf. Clean plants are less likely to develop problems, and washing helps get rid of insects and eggs that are potential pest problems. Other than root diseases, most indoor plants are seldom troubled by diseases because lack of humidity in the home prevents them from developing.
Careful attention to all aspects of growing plants, including their personal needs, makes them welcome friends in your home. Contrary to what some would have you believe, no person is born with a black thumb and plants are happy to respond if they are given the right growing conditions. Give them light, adequate water and fertilizers, and control the pests, and they won't be in high-risk situations in your home.
Larry A. Sagers is a horticulturist with the Utah State University Extension Service.
© 1998 Deseret News Publishing Co.