Most outdoor plants are ready for a long winters nap. Some have lost their leaves and are awaiting the warmer and longer days of spring before they bud out again. Others keep their leaves but slow growth. This self-induced dormancy helps plants to survive our winter. A few plants prefer cold weather (pansies, kale, cabbage and several lawn weeds), but they will also grow more slowly when temperatures drop.
House plants get to enjoy the warmth inside with us. They will not generally go dormant; however, this does not mean that houseplants are immune to winter. They also realize that temperatures have dropped and the day length is shorter. Houseplants will also go into a slower growth phase, awaiting the return of spring. Here are a few ways to help houseplants handle winter well.
Know the temperature and light requirements of your houseplants, and try to provide the best possible growing conditions. Most house plants are tropical plants. They actually prefer warm weather year-round. For best winter survival, try to keep temperatures above 55 to 60 degrees. Many house plants are damaged by lower temperatures, but there are some exceptions.
While few houseplants can stand temperatures below 40 degrees, some actually prefer winter temperatures in the 40s. These include Sansevieria (snake plant), grape ivy, English ivy, Hoya (wax plant), strawberry begonia and most of the ferns. Christmas cactus and cyclamen are two hardy blooming plants.
Other houseplants prefer warmer weather but can stand temperatures in the 40s. These include wandering Jew, Pepperomia, dumb cane (Diffenbachia), Chinese evergreen, asparagus fern, spider plant, cast iron plant (Aspidistra) and Schefflera.
House plants that can stand very little cold include African violet, Persian violet, philodendron, prayer plant, weeping fig (Benjamin fig) and most palms. If you do not see your plants listed here, look up their temperature and light requirements online.
Know how much light your plant needs and supply it. Light levels are lower during the winter, so place plants where they will get plenty of light. South- and west-facing windows will usually be the sunniest in the winter.
Plant lights help to add more light if you cannot get enough sunlight, but they are often not bright enough to supply all the light needs of plants. If you use a plant light, buy a light that is designed for plants -- often called grow lights. If you do not have one of these, use a fluorescent light. Place grow lights as close to plants as possible to get the most benefit.
Reduce fertilization by half during the winter. Growth is slower when temperatures are cooler and less fertilizer is needed.
Water the plant well when the soil dries to a depth of 1 inch or more. Stick your finger into the soil slightly to see if water is needed. Plants will usually need less water in winter. Add water until it runs out of the bottom of the pot.
Humidity is lower during the winter. Houseplants dry out more rapidly, causing problems such as brown leaf tips and leaf edge. Low humidity is a serious problem. Think about how dry our skin gets in the winter. Many problems of house plants in the winter are due to low humidity.
Spraying the plant with water only increases the humidity for a while. To increase humidity in an area, group plants together. You can also place a shallow pan of water near plants. The water will evaporate and increase humidity in the area. You can even place plants in a shallow tray filled with gravel with a little water in it. The water evaporates and raises the humidity. Never let the water level be so high that the water touches the bottom of the pot. Humidifiers can also help. Plants that are susceptible to low humidity include Norfolk Island pine, most ferns and any plant that is receiving too much light.
Once plants make it through the winter, renovate them next spring. Repot them if necessary. Prune off the dead parts, drench the pots with water letting it run through the pot and then re-fertilize. This will prepare them for growth next year.
Willie Chance works with the University of Georgia Center for Urban Agriculture.