Consider some of the following tips for overwintering your favorite plants indoors
Gardeners in Minnesota know all too well that summer warmth and sunshine will eventually give way to winter chill and hazy skies. While some plants are perfectly able to die back and return on their own the next spring, others rely on your hospitality to make it to the next year. When frosty nights are on the horizon, consider some of the following tips for overwintering plants indoors.
When should I bring my plants in?
For most plant species, overnight temperatures below 50 degrees Fahrenheit entail a risk of plant damage or death. However, you don’t want to wait until your thermometer finally hits that ominous 50 degree reading and then abruptly cart all your plants inside. Such a sudden environmental change risks shocking your plants, and that shock may cause plant damage or death of its own. It’s important to give your plants time to adjust to their new overwinter environment.
How should I prepare my plants for moving indoors?
If the plants you’re moving are in a container light enough to lift, simply wipe any dirt from the container and be sure to check for pests as mentioned below before taking the container indoors.
If your plants are rooted in the ground or in a heavy container that can’t be brought indoors, you’ll need to decide whether to transfer the plant to an indoor container or simply take cuttings, seeds, or bulbs to start fresh next year.
If you decide to repot the plant, dig it up from its current home while making sure to get as much of the root ball as possible, then move the plant to its new pot. Fill in around the plant with fresh soil, then give it a good watering to help it adjust to its new container. Keep this repotted plant outdoors for at least a few days before trying to move it indoors – one stressor at a time!
Check for any browning and/or wilting leaves or flowers and gently remove them. This helps the plant to focus its energy on supporting healthy tissue. Continue this light pruning throughout the winter, saving larger pruning efforts for spring.
Some plants, such as geraniums, can be overwintered as bare-root plants. Check out Overwintering Geraniums | UMN Extension for more information on this unique approach. Similarly, bulbs are adapted to a winter “dormancy” period and require some unique care. Articles such as Growing bulbs indoors | UMN Extension can help you learn more about techniques for preserving such plants for next year.
What about pests?
A critical step for overwintering is to ensure that your plants are as pest-free as possible before bringing them into your home. The last thing you want is to bring in an opportunistic pest that infects your healthy houseplants!
For many plants, simply investigating for signs of pests and giving the plant a gentle wash or wipe with a damp cloth may be enough. It’s also a good idea to put any plants that you’re hoping to bring indoors in a brief “quarantine” period. A three-season porch or windowed attic can be a great place to give your outdoor plants time to acclimate to an indoor space, as well as to give you time to watch for any unwanted hitchhikers.
The University of Minnesota promotes an Integrated Pest Management approach. This simply means choosing the least drastic method for controlling pests first, and only moving to more aggressive means of pest control when necessary. See Preventing pests in your yard and garden | UMN Extension for more information.
Once they’re indoors, how should I care for my plants over the winter?
Many plants will want to escape the winter freeze but will also prefer to avoid steamy summer temperatures over the winter. If your plants have been thriving in 60-70-degree, semi-dry outdoor weather, try to find them a similar environment in your home. You might start by keeping the plants in a three-season porch or windowed attic, where the climate will be similar to that of late fall. Gradually you may bring the plants into your general living space, however, do this over time and watch for signs of stress.
Once your plant is in the container where it will spend the winter (and after giving it that first good soak if it was repotted), decrease your watering to help your plant adjust to the drier conditions of colder months. For most plants, you can wait until the soil is almost dry before adding water. Place your finger in the first inch or two of soil – if the soil is still damp to the touch, wait another day and check again. As always, be sure to read up on the needs of your specific plants. Succulents and cacti, for example, will want very little water over the winter months, and may die if overwatered.
What about light?
Your plants will likely have become accustomed to an abundance of light while living outdoors. Before bringing them indoors, try moving them to a shadier spot in your yard for a few days to encourage them to adjust to reduced light. When you first bring them inside, you will likely want to keep them near a window that gets plenty of sun. For the most part, the more light you can give your plants during winter the better – and some plants may even thank you for picking up an LED light to supplement their winter solar demand.
Winter doesn’t have to mean the end of your gardening fun! Help your plants dodge the winter chill so that you can bring them back out into the sunshine come spring. By following the steps above and learning about the unique needs of your favorite plants, you can keep many of them thriving year-round. If you’d like to take a deep dive on the subject of winter garden prep, consider signing up for the UMN Extension’s “Fall into Winter” course found at https://www.ramseymastergardeners.org/classes.
About the Author
Scott Lore is a first year volunteer with the University of Minnesota Extension Master Gardener Volunteer Program. He lives in Saint Paul with his wife Sam and their two cats, Yoshi and Toph. Scott is passionate about nature, photography, writing, music, and tabletop games. His enthusiasm for gardening stems from a long-term goal of being able to sustainably grow his own food, cultivate native species, and support pollinators to help our environment thrive.
Photo Credit: Nong on Unsplash