By Darrell Blackwelder
For Farm Carolina
SALISBURY - Cooler temperatures and falling leaves are a sure signal for those with houseplants outdoors to strongly consider moving them indoors soon. Nighttime temperatures dipping down to the 40-degree range will damage some houseplants.
Houseplants such as rubber trees, philodendron, pathos and even Christmas cactus are actually tropical understory plants. The cell structures of these plants contain more oils and waxes than plants endogenous to the Piedmont. Waxes and oils within the cells solidify under waning night temperatures, rupturing cell walls. Cold damage is manifested by internal browning on the leaf margins of plants. Rubber tree plants are easily damaged at temperatures of 42 degrees.
The indoor environment is a difficult transition for most houseplants coming in from a long summer vacation. Moving plants indoors from bright sunlight of nearly 10,000 foot candles to 5-15 foot candles often initiates premature leaf drop. Ficus trees, or weeping fig trees, are very sensitive to deviations in light intensity. These trees and other plants experience premature leaf drop. New leaves adjust well to low light levels.
It is important to emulate an indoor environment similar to the outdoors. Move houseplants to an area indoors that has high natural light. Avoid placing plants near drafty doors or forced air heating vents.
Occasionally mist house plants or place groups of plants on pans of rock filled with water. Evaporating water increases the level of humidity around the plant. Implementing an electrostatic humidifier to the room is an excellent method of keeping the air moist.
Houseplants on outdoor vacation this past summer are also subjected to a number of insect pests. Check houseplant foliage and stems for aphids, scales or other insect pests carefully before bringing indoors.
Use recommended houseplant sprays to control insect pests outdoors a few days before bringing them indoors for their winter rest. Eggs and immature stages of spiders, ants and other insects may be lying dormant in the soil media of the house plant. People who have plants with insects may want to drench the soil media three days before moving indoors with an indoor insecticide. Drenches will control many, but not all insects hibernating in the soil. Always read and follow pesticide labels before applying any pesticide.
Fertilization is generally not recommended on houseplants during the winter months. High soluble salt build-up from winter fertilization often burns the roots, reducing vigor and eventually killing the houseplant.
Darrell Blackwelder is the County Extension Director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County. Call 704-216-8970.