Temperatures For House Plants

The growing temperature will be determined by the comfort of the humans living in the house. Fortunately most house plants and people are comfortable at the same temperatures. However, houses are not at a uniform temperature throughout. Some rooms are cooler or warmer. Even within a room, some areas are cooler or warmer than the rest of the room.
Temperature affects plants in several ways. Some plants require a drop in night temperature to bloom. If a plant is given all the factors needed for maximum growth, but the temperature is too cool, the plant will grow more slowly than it could.

Most plants will not adapt to rapid temperature fluctuations as can occur near a doorway in the winter. Each time the door is opened, nearby plants get a blast of cold air. The same is true of a plant growing near a furnace vent or a heat generating appliance. Drafts which are too warm or too cold can cause drop of leaves, flowers or flower buds.

In winter, cold temperature injury can occur on window sills. Behind closed drapes, the temperature of the air around the plant drops rapidly. When the outside temperature is very low, and its windy, the window sill temperature can get low enough to cause chilling injury. Chilling injury can occur when the temperature is as high as 45 degrees. Plants susceptible chilling injury will not recover if long exposure to low temperatures. When the temperature of the glass is below freezing, plant parts actually in contact with the glass, will be frosted.

High temperatures are also a problem. The most common symptom is wilting. If the temperature is high enough, plants growing in moist soil will wilt. This may lead inexperienced gardeners to overwater a plant wilted due to high temperatures.

The leaves exposed to sunlight may be several degrees warmer than the surrounding air. In this instance the high temperature problem is internal to the plant. Plants growing in sunny windows are most affected.

When plants are moved during the winter it may mean a trip outside. Always cover the plant with a plastic or paper bag and warm up the car before putting the plant in it.