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For many years I have written about the care of various houseplants during the dormant season. In recent articles I have written about African Violets, tropical ferns, Norfolk Island Pines, Amaryllis and peace lilies. In each of those articles I mentioned my own failures with all of these plants. When I read an article by Carl Hoffman, Extension Horticulturist, on how to kill a houseplant in five easy steps, I felt somewhat better.

Hoffman states that the first way to kill a houseplant is to place the plant in insufficient light. Plants require light to convert carbon dioxide and water to sugar through the process of photosynthesis. The three most important characteristics are intensity, duration and quality.

Intensity refers to the brightness of light. This influences the plant's ability to manufacture food, promotes growth and flowering. Some plants tolerate a very low intensity of light while others require much higher intensity to grow and develop.

Duration is the second characteristic of light and can be defined as the length of time a plant is exposed to light. This time is referred to as day length and is important to flower bud initiation and proper shoot and leaf growth. The blooming times of poinsettias and Christmas cactus, for example, are determined by day length.

The third characteristic is the quality of light. In many cases, good plant health can be maintained by simply moving the plant to a site where there is adequate light. This could mean moving it closer or further away from a window, placing it in a different spot in the room, or moving it into a different room entirely.

According to many, including Hoffman, over watering a plant will kill it. In fact, it is the number one reason why indoor plants die. All the plants I wrote about recently need good drainage. Most plants need to be watered when they feel dry, watered thoroughly, and the excess water poured off.

The third reason why indoor plants die is because of improper fertilizing. The two biggest mistakes made in fertilizing are over fertilizing plants growing in low light and to fertilize plants when they are not actively growing. Plants growing in low light often show weak, spindly growth, which tempts us to attempt to correct it with fertilizer. In reality, the plant is suffering from low light, which limits its ability to change into food and utilize the nutrients that are already present. The addition of more fertilizer just adds to the stress.

A plant that is dormant during the naturally low light months of November through February will need fewer nutrients. Over fertilizing can result in burned leaves and roots and will result in the death of the plant. A good rule is to fertilize houseplants every two weeks from March through September with a water soluble fertilizer mixed at one-half the rate listed on the label.

Planting in an unsuitable potting medium is the fourth way to kill houseplants. A plant's soil has three major functions. They are to anchor the roots, provide the plant with minerals and nutrients, and allow air to reach the roots. The root cells of plants carry on aerobic respiration similar to human cells, and like human cells, if they receive insufficient oxygen they will die.

Outdoor garden soils are generally too compact for good growing conditions. It also must be pasteurized to destroy disease organisms, insects, and weed seeds. It should be amended with equal parts of organic matter and drainage material. Pasteurized compost or peat moss work well as organic matter while perlite or sharp builder's sand serves as good drainage material.

The fifth way to kill houseplants is to place them in an area with insufficient humidity. Brown leaf tips and edges are often the results of low humidity. Most of our houseplants are really forms of tropical or subtropical plants and their native habitat is very humid. Their native humidity is 80 percent or higher, while we must be realistic to have humidity of 30 percent. One can help the plants by having them all in the same area, with those that need the most humidity in the center. A room humidifier has the advantage of increasing the humidity in the entire room or home and thus allows one the freedom to place plants where we wish.

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VOICE MAIL: You can leave a question for a volunteer Master Gardener at our new phone number, 651-213-8904, any time of day or night. You can also get your question answered on the web at: www.extension.umn.edu/askmg.

The Chisago County Extension Office is now sharing office space with Veterans Administration in the Senior Center building at 38794 6th Avenue in North Branch.

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Plans are underway for our Gardening Bonanza Town and Country Expo to be held in North Branch March 8.

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Information on our spring events, including the plant sale will be mailed about Jan. 15 and posted on our website www.extension.umn. edu/county/chisago/mg.

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