Garden Variety: How to transition your plants indoors for winter
This week’s frosty overnight temperatures have had gardeners and plant enthusiasts scrambling to move tropical plants and tender annuals indoors for the winter. Protection from the cold may seem like the most important thing for keeping sensitive plants alive for the winter, but you should also consider the species of plant, the light and space and the overall health of the plants.
The first thing to consider when moving plants indoors is the plant species. If they were indoors last winter and moved outdoors for the summer, they should be fine inside again, although they may undergo a little stress from the change of environment. Tropical plants, typically sold as houseplants, can also be kept indoors over the winter. Sometimes gardeners want to bring in annual herbs such as basil, or annual flowers such as impatiens and begonias that are grown in containers. These species are a little trickier.
Light and space
When deciding what to move inside, light and space are important factors. For example, if you have a sunroom or space in front of sunny south-facing windows, go ahead and bring in the basil or that big tropical hibiscus. If space or light is limited, rehoming the hibiscus and tossing the basil in the compost bin might be better options. You can always start fresh in the spring.
Most importantly, all plants need light. Put more emphasis on getting plants near a window than thinking that that palm tree looks good in the dark corner of the living room. South and west windows typically provide the most light and are appropriate for tropical plants with high light requirements. North and east windows provide less light and are more appropriate for tropical plants that tolerate medium- to low-light conditions.
Inspect for insects
Once you have decided which plants to keep indoors and where they will go, inspect plants closely for insects. There may be spider mites or aphids on the leaves, or you may find pillbugs burrowing in the potting mix.
To check for small insects on the leaves, hold a white piece of paper under the leaves and tap the leaves and stems to knock insects loose. You will be able to see them more easily crawling on the paper than on the plant. If insects or mites are found on the leaves, seek appropriate treatment targeted to the pest. Left unchecked, they cause stress to plants and could move to other nearby plants as their population grows.
To check for insects in the soil, set the pot and plant into a tub of lukewarm water. Most insects will come out for air once the soil is wet.
Some gardeners like to repot plants at this time, but repotting only creates more stress for plants that are already undergoing a big environmental change. Late winter or early spring is a better time to repot plants.
Plant health and care
Inspect for signs of plant disease. Leaf spots are generally not detrimental to plants, but infected leaves can be plucked and disposed of to reduce the diseased area and prevent further spreading. If stems are soft, have brown lesions or show other signs of disease and decline, disposal may be a better bet.
Healthy plants placed in appropriate light conditions for their species have the best chance of survival inside the home. Once you have determined what can be overwintered and where, the only winter care needed is occasional watering. Let the potting mix or soil dry out between waterings. How often this occurs depends on the soil type, plant, temperature and humidity to which the plant is exposed. Always check soil moisture rather than watering on a schedule. Many indoor plants do not need much water over the winter.
Wait to fertilize until plants are actively growing again in late winter or early spring.
— Jennifer Smith works in regulatory horticulture and has worked as a horticulturist for various government entities. She has experience in landscape design and maintenance and as an educator.