Good news, plant lovers: the end of the outdoor gardening season does not have to mean the end of your container plants. Although most will not survive the winter in cold climates, they can be brought indoors as houseplants to help them make it through the colder months. Once nighttime temperatures become cooler, it's time to think about bringing your more delicate or temperamental plants indoors (that includes any vacationing houseplants that you brought outdoors in the spring). With a bit of strategy and a little tender loving care, your outdoor beauties can make it through winter unscathed and ready to enjoy another season outdoors come spring.
Choose the Right Plants
Successfully overwintering plants indoors starts with choosing the right type of plants. Contrary to popular belief, not all plants can survive indoor growing conditions (or at the very least, not all plants can thrive indoors), especially if your home has limited light, warmth, or humidity. There's a good chance that there are fewer sunny spots inside your house than in your yard, so you'll have to make some tough choices about which plants are worth keeping for the season and if you can give them the care they require indoors.
Although it's tempting to move all outdoor plants to the indoors for the winter, it's also impractical. Before you make the decision about which plants to move indoors, run through the following checklist and move the plants that meet the following criteria:
- Keep only healthy plants. If a plant has been struggling all summer under the best of conditions, it's probably not going to improve indoors. It's time to face reality and send it to its final resting place in the plant graveyard (also known as the compost bin or trash).
- Never bring a plant indoors that is infected with pests or diseases. Problems spread more quickly among indoor plants than in the outdoor garden, and even if you take great care to quarantine the troubled plant until it's been coaxed back to health, there's no guarantee that you won't spread the issue to your other plants. Also, no natural insect predators occur in the house, making the conditions ideal for infestations to occur. Inspect all plants thoroughly for any signs of problems before you bring them indoors.
- Give priority to your favorite plants. When deciding which plants to bring indoors for the season (assuming you have limited space), give preference to any varietals that you've already invested a lot of time and energy into, like the ferns you've been coddling for years, anything you've trained into a standard, and sentimental favorites. Of course, expensive splurges are worth the effort too, if you have the room.
- If the plant would look good as a houseplant, bring it indoors. Many homes have enough light to successfully grow several flowering varietals like geraniums, fuchsia, begonias, and even passion flower, all of which can bloom beautifully indoors. Sure, they might not look as lush or vibrant as they would outdoors, but it's still nice to have something flowering in winter, and the plants will be ready to start blooming again outdoors in the spring.
- Consider giving priority to certain vegetables, like small pepper or tomato plants. They're actually tropical perennials and, when they receive enough sunlight, will continue to produce fruits all through winter. However, some vegetable varieties might need an especially large pot, so you'll have more success growing compact patio varieties—cherry tomatoes and small-fruited peppers like chilies that will fruit easiest and produce a higher yield. Keep in mind there are no insects or gentle breezes indoors to pollinate your plants, so you will have to pollinate them manually.
Alternatives to Bringing Plants Indoors
It's important not to overlook that some of your plants, like tender perennials, may actually benefit from a period of dormancy in the winter months. Plan to overwinter varietals like potted lavender and rosemary in your garage or basement; if the temperature doesn't dip below 20 degrees Fahrenheit or above 40 degrees Fahrenheit, they won't freeze but will stay dormant. Take care not to let the pots dry out or stay overly wet—water them only when the soil becomes dry a few inches below the surface and allow any excess to drain out.
When deciding on a winter plan of action for your outdoor plants, be realistic about your available space and winter light. Remember, even if you choose not to bring an entire plant indoors, you can always start cuttings from the mother plant. They'll take up far less space and can even do better than established plants throughout the winter because they won't suffer the shock of having to adapt to new growing conditions. The young plants will have time to develop their root systems during winter and will be ready to be moved out into the garden and start growing in the spring.
Once you've decided which plants to move indoors, give them time to acclimate to being houseplants. Bring them inside while the windows are still open and the temperature indoors is about the same as outdoors. That way, they'll be able to adjust to the change in temperature and humidity more easily rather than waiting until a frost is expected and then bringing them into a dry, heated home.