BRINGING HOUSEPLANTS INDOORS FOR THE WINTER
By Dr. Leonard Perry, Extension Professor
University of Vermont
If you let your houseplants "vacation" on the back deck or front porch this summer, then by early September, it's time to start getting them ready to move back inside for the winter.
Because conditions differ widely between the inside and outside your home, a gradual reintroduction to the indoors is best. Sudden changes in temperature, light, and humidity can be traumatic to plants, resulting in yellowed leaves, dieback, wilting, and even death.
First, get ready for the move indoors. Clean the windows--both inside and out--to ensure that plants will get adequate light this winter. If some of your plants will need repotting, make sure you have sterilized potting soil, containers, and the supplies you need on hand.
This is also the time to add ceiling hooks for hanging plants or build that wide shelf in front of the window that you've always wanted. If you have a lot of plants that require high humidity, you might want to make the shelf wide enough to accommodate trays to group these plants together. Line the trays with waterproof material, fill with gravel, and place the pots on top. Keep the gravel moist.
You will need to bring your plants indoors before nighttime temperatures dip below 45 degrees F. Most tropical plants will suffer damage at temperatures below 40 degrees F, a few at 50 degrees F.
Inspect plants for insects and diseases, and treat as appropriate before bringing plants back inside. Check the outside of the pot for signs of soil or unwanted inhabitants. Soaking the pot in a tub of lukewarm water for about 15 minutes will force insects out of the soil. If snails, earthworms, or other insects burrowed in the soil, you might want to repot the plants, placing a piece of wire screening over the drainage hole to keep them out next year.
If necessary, repot plants in larger containers. If plants have gotten leggy during their outdoor stay, remove from the container, and prune the top and roots in equal proportions. Scrub the pot, add fresh potting soil, and replant.
This is also a good time to take cuttings of annual flowers, such as impatiens, begonias, geraniums, and coleus. They root easily in water or sand and make attractive houseplants. This is also a good way to overwinter them for planting in the garden next year.
Take cuttings about three to four inches long. Remove the bottom leaves, and place the cut end into a mix of peat moss and perlite. Dipping the end in root transplant hormone encourages faster rooting. Keep the rooting medium moist but not wet. When the cuttings have rooted, transplant into small pots. As the plants grow, repot as soon as the plant has outgrown its current pot.
To prevent shock when you bring houseplants back indoors, expose plants gradually to reduced lighting. Usually, if they've been in bright light and you move them into much lower light, expect some leaves to fall off. However, new ones should form as the plants readapts to the lower light. Itís best if they've been outside in high light to put them in similar light indoors like a south window or under plant lights on a timer for 16 hours a day.
Don't overwater! Although our dry summer meant you probably had to water your container plants every day, indoors they won't require as much water. Let the soil surface get dry to the touch before watering again. Water succulents less often, when the soil is dry for several days. Donít water if quite cloudy or rainy weather as plants wonít get sufficient light indoors to dry out.
Finally, give your plants a boost of fertilizer, according to the directions on the product label. Plants that have been repotted with soil containing fertilizer will not need to be fed again for two to three months.