During the winter months, maintaining indoor plants can be as rewarding as outdoor gardening. The following are some rules to observe to help keep your houseplants healthy.
Reduce fertilization. During the cooler temperatures and shorter days of the winter months, the growth rate of most houseplants slows. Resume regular fertilizing in late April or May when new growth begins.
Do not overwater, which encourages root rot. Most plants should not be watered until the soil feels dry. Clay pots are more porous than plastic pots so need to be watered more often. Use room temperature or tepid water (never cold). Mist daily and periodically clean larger leaves with a damp cloth. This helps to eliminate dust and dirt from the leaves, which can clog pores and reduce the amount of light to the leaves. It adds moisture and prevents pest infestations.
Hot, rising air dries soil in a hanging pot. Areas near windows are cooler in winter. Bathrooms and kitchens are high in humidity. Areas near heat vents are hot and dry.
The optimum temperature for most indoor plants is between 16C to 26C, dropping around 5C at night. Placing a newspaper between the plant and the window at night will help prevent damage from the cold.
Provide proper light conditions. Plants that do not get sufficient light become leggy and weak. South and east facing windows provide the most light. Because of the low light levels of winter, some plants should be relocated. Houseplants on the north side of the house should be moved to east windows, and the east side plants should be moved to the south windows. Periodically check plants on south facing windows as low winter sun angles may cause scorching.
Ensure good air circulation, which will help prevent disease and pest problems. Turn on a fan during the winter months and occasionally open a window for a short while.
Use a soil-less mix or pasteurized soil to prevent disease and insect problems. Both are devoid of harmful organisms. Plants grown in a soil-less mix, which is sterile and has no nutrients, will need more fertilizer than those grown in an organic soil. Choose a light enough soil to ensure good drainage and air circulation around the roots.
Check all house plants closely for pest infestations. Isolate new plants for two to three weeks to determine that they aren’t carrying any pests. If any are found, spray insecticidal soap every few days. Make sure to apply on undersides of leaves where many pests accumulate. Mealy bugs can be killed by touching them with a cotton swab dipped in alcohol. If a plant is heavily infested, dispose of it to avoid the pests from spreading to other plants in the house.
Repot houseplants that have grown too large for their containers. (Some plants, such as African violets and Christmas cactus, bloom better if slightly root bound.) Cut back leggy plants to encourage compact growth. Turn and prune houseplants regularly. Pinch back new growth to encourage bushy plants.