When the weather turns cold in winter, many of us begin moving our potted plants to warmer locations which typically include inside the house. But adverse conditions inside a home can make caring for houseplants challenging, even without the freezing temperatures.
The most important factor for indoor plants is adequate light. Flowering plants, plants with highly colored leaves, and succulents will grow best in a window where they receive full sunlight. Foliage plants, such as ferns and philodendrons, will prefer a window receiving indirect light such as a north-facing window. Artificial lighting can also be used to supplement natural light as needed.
Most plants grow well indoors with temperatures between 65-75oF but sudden changes can injure plants. Avoid hot or cold spots, including near the TV, in the path of heater vents, and windows that are not energy efficient (letting a lot of cold air in at night).
Humidity is another factor to consider. Most plants grow best at 40-60% humidity with the average home being well below 40% during winter. Low humidity levels will cause your plant to lose water from the leaves faster than the roots can absorb water, causing brown leaf tips and flower buds to drop. Installing an inexpensive humidifier can help, as well as placing plants close together or on a bed of wet gravel. The gravel should be 2-3” deep but never allow the plant to sit in water. As the water evaporates, the humidity level will increase around the plant.
Over-watering is the number one cause of indoor plant death. Be sure to water only when the soil feels dry, when the soil shrinks away from the sides of the pot, or if the pot feels light when you pick it up. When needed, apply enough water until it runs out the bottom of the pot. You can also water from the bottom of the container but will need to water from the top at least once per month to wash out the excess salts that build up. Either way is fine but do not allow water to stand in a saucer too long.
More information: Houseplants