Winter's lack of sunlight, colder temperatures, and shorter days can wreak havoc on indoor plants.
Many popular indoor plants naturally grow in locations that have an average of 14 hours of sunlight, an ambient temperature of 65 to 85 degrees Fahrenheit, and a relative humidity of around 100 percent. During winter months, even optimal conditions are around 8 hours of sunlight a day, temperatures average from 55 to 75 degrees Fahrenheit, and the humidity level is generally between 15 to 20 percent. Plants can adapt to these conditions. They slow down on water requirements, and limit new growth. For all practical purposes, the plants become dormant during winter months. They do not produce new growth, and no new shoots appear. This is a natural resting period. It helps the plant to build up food reserves, and it compensates for the change in environment.
Running the furnace in winter creates a dry environment for indoor plants, and can also weaken them if the plant is placed close to a register that emits hot air. This hot air can encourage growth that will be spindly and weak. Avoid cold drafts as well. Keep plants at least 6 inches from a window. Place them in areas away from exterior doors to protect them from the sudden shock of cold air.
Never fertilize plants during winter months. Doing so encourages growth, and as conditions in the home during the winter are less than ideal for house plants, fertilizing them will produce results that are less than satisfactory. A good rule of thumb is to not fertilize from October to April of the following year.
Plants need as much light as they can get during winter months. Not only is light intensity cut by at least 50 percent during the winter, but a typical double pane window reduces that light intensity by 80 percent. This is why leaves of house plants become yellow in winter. The best exposure is in a window facing south or west. If you have plants that do well during the spring and summer months in a north or east window, then move them to a better location. Supplemental light can help--place a plant under a light source. If using fluorescent light, have the top leaves of the plant 10 to 24 inches away. If using an incandescent bulb, have the top leaves 15 to 30 inches from the light source. Ignoring these distances can result in burned leaves.
Watering needs for indoor plants change during winter months. If you over-water during the winter, you will lose the plant. All but the most sensitive plants should be allowed to wilt slightly before you water them. Keep a close eye on your plants, however, for letting them wilt for too long a period will kill it. It is next to impossible to set up a regular schedule for watering indoor plants. They should be checked on a daily basis to determine watering needs.
TIP: Our expert gardening advisor, Susan Patterson adds, "Do not allow lemon, orange or other citrus trees to dry out over the winter. They require moist soil throughout the cold months."
The best thing you can do for indoor plants in the winter is increase the humidity level. Because heating the home brings the humidity level to 15 to 20 percent, invest in a humidifier. Group plants near the humidifier if at all possible. If this is not an option, consider placing plants in the bathroom or kitchen, where humidity levels are typically higher. You can also create a greenhouse effect by placing the plant in a shallow tray filled with pebbles and water. When the water evaporates, it nourishes the root base, and gives needed humidity.
TIP: susan suggests, "The best way to water plants in the winter is to sit them in a tray with some distilled water. Allow the plant some time to soak up the water and return it to its usual location."
Although caring for indoor plants during the winter means a little extra time spent, if you follow these guidelines you will be rewarded in the spring with a happy, healthy plant. Because indoor plants appear dull and lifeless during the winter, consider buying a few blooming plants to get you through the winter months. Christmas cactus, chrysanthemums, gloxinia and primrose are just a few of the indoor plants that will bring a splash of color into your living area. When choosing the plant, pick one that already is half in bloom. If the plant is merely budding and not blooming, the chance of the buds opening are not good. Remember, you are taking them from a greenhouse to a place where growing conditions are less than ideal. Look for good healthy plants that are green and perky.