Keep only healthy plants. If something has been struggling all summer under the best of conditions, it is not going to improve indoors.
Never bring in a plant with pests or disease. Problems spread more quickly among indoor plants than in the garden. To be safe, in late summer before frost, the plants can be pruned back, given a soapy bath (to remove bugs, dust, mites and spiders) and brought indoors for the winter.
If the plant would look good as a house plant, bring it in and use it as one. Many people have the light to successfully winter geraniums and begonias in full bloom.
Some tender perennials like a period of dormancy in winter. You can winter over potted lavender and rosemary in your garage. If the temperature doesn’t go below 20 degrees F. or above 40 degrees F. they won’t freeze, but will stay dormant. Just don’t let the pots dry out.
If you have the room, consider bringing in some small pepper or tomato plants. These are actually tropical perennials and given enough light, will continue to produce fruits all winter. Tomatoes need a large pot. You’ll have more success growing a compact, patio variety. Cherry tomatoes and small-fruited peppers like chilies or cherry varieties will fruit easiest and give you a higher yield.
Be realistic about space and available light. You can always start cuttings. Cuttings take up much less space.
Give your outdoor plants time to acclimate to being house plants. Bring them indoors while the windows are still open. They’ll adjust to the change in temperature and humidity more easily if the change is gradual, rather than waiting until a frost is expected and then bringing the plants into a dry, heated home.
Outdoor plants thrive during the heat of the summer in the sun and some afternoon shade. Container plants must be watered frequently, and this leaches away the nutrients in the potting soil. Thus, it is important to use either a long-lasting fertilizer or apply a water-soluble product every two weeks for vigorous flowering. Most people trash the plants in the fall. However, they can be cut back into a dense form and used as an indoor foliage plant. Do not fertilize the plants until late March.
*This article was originally published on September 22, 2010