In winter’s short daylight hours and cooler temperatures, houseplants require less watering and fertilizing. But they don’t want to be neglected. In winter and early spring, give plants as much light as possible. Even placing them near a lit lamp during evening hours will help considerably in keeping good health. Incandescent bulbs consume more energy, but because they emit red light waves that can be absorbed by the chlorophyll in the leaves, they are better for plants than LED or florescent bulbs.
Fertilize at least monthly at half concentration. Follow the watering rule when you apply liquid fertilizer, adding enough water so that some drains from the bottom of the container.
Poor watering is a problem I see often in troubled houseplants. Frequently, only the upper half of the root ball appears to have been watered. The lower half is as dry as the Sahara Desert. Often, there is a visible line of fertilizer salts accumulating between the wet and dry regions with concentrations sufficient to burn roots in the fertilizer zone.
Never apply slow-release fertilizers in fall or winter, as they are engineered to release their nutrients during active growth. Adding slow-release fertilizers now will likely cause fertilizer burn as they release nutrients faster because the soil is constantly at room temperature during this period of low light intensity and poor growing conditions.
Don’t put African violets near a window. African violets perform best in diffused light and near-constant temperatures. In windows, the plants are exposed to cooler temperatures in the evening and warmer temperatures during daylight hours. Unlike many plants that would benefit from such a temperature change, African violets will cease to flower and may even exhibit cold damage on the foliage. Place them in the middle of a well-lighted room for more constant temperatures.
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