While the outside winter landscape lays dormant, we can enjoy the sense of “green” that our indoor houseplants provide. However, being inside for the winter months can create a stressful environment for these plants. Winter is probably the easiest time of year to kill a houseplant. If you do not want to be guilty of houseplant homicide, the indoor gardener needs to understand a few basic principles of care.
During the winter, our houseplants experience less than favorable growing conditions. Shorter day length results in lower light levels. Higher thermostat settings result in lower humidity and drier air growing environment. If you want your houseplants to survive and thrive during the winter, you will need to adjust your care practices to suit the winter indoor environment.
The number one problem for houseplants during the winter is incorrect watering. In fact, more houseplants die from overwatering than from any other cause. The water requirement of the plant is influenced by a number of factors, including the species of plant, the amount of light the plant receives, the humidity in the room, the type of potting soil, the room temperature, and even the type of pot the plant is in. Clay pots lose moisture quicker than a plant in a glazed or a plastic pot. Therefore, sticking to a rigid schedule of watering during the winter is not a good idea. Reducing the frequency of watering is the best way to limit the amount of water a plant receives. Your houseplant may only need watering once a week during the winter months.
Most houseplants benefit when the soil can dry slightly between waterings. One way to check the moisture level of the soil in the pot is by sticking your finger an inch deep into the soil ball along the inside wall of the pot. If the top one inch of soil feels dry or the plant begins to wilt slightly, most plants will be ready for another watering. Overwatering will suffocate the root system and create a favorable environment for root rot fungi.
There are exceptions to the “let the plant go a little dry” rule. Potted ferns require consistently moist soil. If in doubt about the watering requirements, do some research regarding the specific plant and its moisture needs. It is essential that you do not allow plants to sit overnight in water that collects in the drainage saucer. When you do water, thoroughly water the entire soil ball in the pot.
The drier winter air can be a problem for the plants — houseplants like 40-50 percent. If you humidify winter rooms, plants won’t need water as often. The use of a room humidifier and grouping plants together can increase humidity. Setting pots above (not in) a tray of water filled with rocks or glass marbles will also increase the surrounding humidity. Plants requiring high humidity are best placed in bathrooms or kitchens, rooms normally more humid than the majority of the house.
Go easy on the fertilizer during the winter. Houseplants do not need a lot of nutrients because many are now under lower light conditions. Maintain the proper indoor temperature for the plant. Houseplants — the exception is cacti — do best in the temperature range between 65° F and 75° F during the day and about 10 degrees cooler at night. Do not place the plants near drafty locations where cold air comes in when doors are opened. Also, avoid hot, dry areas such as near heat vents and keep the plants several inches away from exterior windows. The air around the window can be colder than the room air temperature.
Lower light levels during the winter will limit plant growth. We have fewer hours of sunlight and more cloudy days in winter. To overcome the light reduction, you may want to move your houseplants closer to a bright, southern or western exposure window. Be sure to wash the dust-off plants so leaves can make maximum use of available light. Happy Gardening!