If you’re a plant-mom or plant-dad in Minnesota, you’ve probably heard of the term “winterization”, especially in the context of your garden. For those plants that must stay outside, winterization means preparing them for snow, ice, and freezing temperatures. These hardy plants are native to cold climates, and will simply go dormant or partially dormant for the winter.
But some of your plants still won’t be able to stand up to the harsh Minnesota climate, and should be brought into the house to keep them alive. But which plants can be brought inside for the winter, and how do you care for them properly?
Identifying Plants That Can Winter Indoors
Any plant that isn’t resistant to freezing temperatures can be brought inside for winter. These include:
- Tender bulbs: Tender “bulbs” are plants which develop and grow from fleshy storage structures (bulbs, corms, rhizomes, tubers, and roots) which will not survive our cold winters outside. These include canna and calla lilies, dahlias, elephant ears, some types of begonias, caladiums, and others.
- Houseplants: Most houseplants are native to tropical climates and haven’t adapted to the cold, so you should bring them in well before the first frost hits. Watch the forecast for temperatures nearing 50 degrees fahrenheit and bring your plants indoors before the temperature drops any lower.
- Annuals: Plants that are sold as annuals in garden centers should also be brought indoors if you would like them to survive the winter.
Preparing Your Indoor Space
Your houseplants and annuals are going to be wanting two main things once they’ve moved inside: light and water. Your indoor space should be able to provide both.
Prepare a space next to your south facing windows for your plants to make sure they get the best exposure to light during the darker winter months. If your southern windows still don’t provide enough light, consider investing in a couple grow lights to help your plants along.
You’ll also want to clear the area of any debris, and if there are any outlets or devices nearby, consider covering them — you don’t want to do damage when misting your indoor plants.
Because your home will likely be running the heater frequently throughout the winter, you should consider investing in a humidifier. This will keep your plants from becoming damaged by the dry air.
As for your tender bulbs, you’ll want to prepare an area in your basement (or a similar area) for their storage. This is because the bulbs should be kept in a location with temperatures between 35 and 45 degrees Fahrenheit, and with a relative humidity of about 50%.
Repotting and Maintenance
Most tender bulbs should be dug after the foliage dries up or after the first frost. Dig carefully to prevent damage, loosen the roots gently by digging several inches back from the plant on all sides before lifting the clump. Shake off excess soil as you are digging the bulbs and cut off the stems and wash the remaining soil off. Discard any damaged bulbs. Let the bulbs cure (dry) before putting them into storage, usually for 1-3 days. Store the dried bulbs between layers of peat moss, sand, vermiculite, sawdust, or wood shavings.
Winter is a great time to repot houseplants. Most potted plants need to be repotted as they grow, and it’s optimal for them to be repotted before the next growing season. A good rule of thumb is to increase the size of the existing container by two inches.
To remove your houseplant from its current pot, you may have to slide a knife or trowel along the side to loosen it first. If the roots are coiled, pull them apart or prune them if they’re extremely root bound. Then, add soil to the bottom of the new pot, center the plant, and add potting soil around to fill the container. Water your houseplant thoroughly to moisten the roots and settle the soil.
(Note: Your houseplant may go into shock after repotting. To avoid this, try to keep the plant out of direct sunlight for a few weeks and keep the soil evenly moist while the plant recovers.)
To maintain your houseplants, place them in a huddle with each other – they will be able to maintain humidity this way. They also need to be placed at an appropriate light source and around (if you have one) a humidifier. Mist them as often as needed.
Annual plants that are being grown in containers can often be moved indoors as they are, but it’s also possible to transplant garden plants into pots and move them indoors. First, cut back the plant to reduce its energy consumption. Then, carefully dig up the plant’s roots and move it to its own pot filled with commercial potting mix.
Another way to overwinter annuals is to take cuttings from your existing plants. To do this, remove any leaves from the lower half of each cutting, and insert the bottom third of the stem into a container of moist potting soil. Place a plastic bag over the pot, supporting it with skewers, twigs, or stakes to keep the plastic up off of the plant. Set the pot in location with plenty of bright indirect light, but preferably not in direct sunlight.
Pest Prevention and Management
To prevent pests in your tender bulbs, inspect the bulbs for insects or diseases before placing them in storage. Consider dusting the bulbs with an insecticide-fungicide mixture labeled as a preventative.
You’ll want to inspect your houseplants and annuals for pests as well before bringing them inside. Make sure to turn over leaves to check the undersides and look closely along the stems. Spray any pests you see with insecticidal soap. Even if you don’t see any bugs, it’s a good idea to wash your plants with a strong spray of water from the hose.
Preparing for Spring Transition
Most bulbs can be stored for up to a year, but tend to perform best when planted within six months of being dug up. For tender bulbs, be sure to plant in the spring following the fall in which they were removed from the soil.
When spring conditions have melted the snow and warmed the air, your houseplants can be transplanted into the outdoor garden or simply moved outdoors. Before relocating them outdoors permanently, It’s a good idea to help your houseplants acclimate by giving them increasingly long outdoor visits over a period of a week or two to avoid shock. In general, most plants are safe to plant outdoors when nighttime temperatures remain reliably above 50 degrees Fahrenheit.
You’ll want to acclimate your annuals in the same way you acclimate your houseplants. Then, you can either keep your plants in their containers outside, or plant them in your garden.
Let The Professionals Prepare Your Landscape for Winter
Whether it’s a houseplant, tender bulb, or an entire garden, a proactive approach is key to ensuring your plants survive the Minnesota winters. Need help with winterizing your garden or landscape? Leave it to the seasoned professionals at McDonough Landscaping. At McDonough, our experts have a wealth of experience in working with Minnesota’s unique climate. Give us a call today at (651)755-7901 — we look forward to helping your plants thrive year-round.