Bringing plants indoors for winter

It is definitely time, for me at least, to call it quits for the outdoor gardening season, 2024. It was a vastly different gardening season from the last one. An abundance of rain in the spring and summer produced a lot of lush growth for trees, shrubs, perennials and annuals as well. Unfortunately, it also provided optimal conditions for weeds. On the days it was not raining and I could work outside I could not keep up with the weeding and deadheading, and so all my gardens are vastly overgrown. I have been scrambling, as you may well be, in the last few weeks to try to weed, cut back and trim so that I don’t have quite so much to do in the spring. But I am finally ready to concede and lay down my tools until next spring.  

  One of the last things I did was to bring in the few ‘houseplants’ I brought outside for the summer. Often we succumb to the lure of plants that are not hardy in Minnesota, very often tropical plants, when we see them in the garden centers. They may do very well outside in a hot and humid summer but they are unlikely to survive our cold winters. If you are satisfied with treating them as annuals, you can leave them outside for the winter and see what happens. But if you would like to give them a better chance to survive the winter you could pot them up and bring them indoors to overwinter. If you do this make sure to check them over for insects before you bring them in. Outdoors there may be natural predators for these pests but you are unlikely to find them in your house and they could infest other plants. (Speaking of natural predators I have noticed a lot of Asian Lady Beetles hovering around my doors trying to gain entry. You may want to watch out for them.) Also when you bring plants indoors they are unlikely to find the same kind of growing conditions that they thrive on outdoors.

 There are two challenges to growing plants indoors in Minnesota in the winter; light and humidity. Different plants have different light requirements, but when they are light-deprived they can show similar symptoms, they may grow spindly, shed older leaves, variegated leaves may turn solid or flowering plants may fail to produce buds. There are three factors to determine when evaluating light: intensity, which is the brightness; duration, which is the number of hours of sunlight in a 24-hour period; and quality, which is the wavelength or color of the light. Plants use red and blue light to produce food. In Minnesota winters the intensity and duration are limited, so it is imperative that you place plants so they receive the needed amount of light.

   Humidity is another challenge to growing houseplants in Minnesota. Heating our homes tends to leave them dry, especially if you have forced air heating. Plants that are losing moisture through their leaves (faster than they are taking it up through their roots) can be identified by browning leaf tips, yellow leaf margins, shriveling, and wilting or even bud drop. Plants with too much moisture can experience root rot, mold or mildew, therefore water only when necessary, not on a schedule. You can also use a room humidifier, which is good for you as well as your plants. Keep your plants away from drafts and radiators, both of which will dry them out. Use a good soil mix that will hold water longer and keep the temperatures a little lower in your home.

  Try placing your plants on a tray of pebbles covered with water, and group plants together so they can benefit from the humidity generated by each other. Place your plants in humid areas in your home such as in the bathroom, near the kitchen sink or over an aquarium; just be sure that they are receiving adequate light.

  One of the plants I am brining in from outdoors is a geranium – a gift from a late friend. She overwintered this plant and other geraniums for many years, and geraniums are a favorite overwintering plant for many. You can bring them in in their original pot or dig them up and repot them in a sterile container. They will most likely drop many of their leaves when you bring them indoors due to the change in their growing environment. Trim them back about one third in order to encourage new growth. If you wish to keep them actively growing be sure they receive adequate light and water. They like bright sunny light so place them in a southern window. Water them when the soil is dry to the touch.

  You can also keep geraniums over the winter in a dormant stage – which is what my friend did and I continue to do. Move the potted plant into dark storage before the first frost. A basement or heated garage where the temperature is 45°-50° will be best. Water about once a month. In the spring place the plant in a sunny window and water regularly. Clean the soil of plant debris and prune off dead leaves and stem. Fertilize once you see signs of new growth. Once the temperatures outside are consistently above 65° you can move the plant back outside for next summer.

  I will now take a rest from plant tending and then I will think about replenishing my supply of houseplants, which has dwindled over the years. We can talk more about that next time.

  Autumn is a second spring where every leaf is a flower – Albert Camus