You don't need a greenhouse or equipment. All you need are windows. I save most of my plants on a large, glassed-in, north-facing porch. Others are scattered about on a smaller, south-facing back porch and almost every window in the house. Some even spend the winter under florescent lights in my basement.
I bring plants inside that would be expensive to replace. These include large specimens of palms, bananas, dracaenas, mandevilla, flowering maples, hibiscus, cactus, succulents, angel trumpets and other tropical plants. Cannas and dahlias can also be saved, but since they go dormant in winter, they can be allowed to frost and be stored later in the basement. They're not my priority right now.
True annuals that complete their life cycles in a single season aren't worth saving. These include petunias, flowering tobacco, zinnias and marigolds. What's confusing is that many plants that we grow as annuals are actually perennial in frost-free climates. So it may be well worth your time to save such things as geraniums, blood leaf, lantana, oxalis, begonias or coleus. You may wish to save the whole plant or to take cuttings from it. It may come down to a matter of available space. You can always take the "mother" plant inside now and take cuttings later.
You'll be surprised how many plants you can squeeze together in a sunny window. They may not look quite as lush and colorful as they did on the sunny patio, but the main point is for them to survive. In addition, all those plants in your home will help improve the air quality by filtering out carbon dioxide and other impurities and releasing oxygen. And for the gardener in winter, it's great to have an indoor jungle to fuss over until spring arrives.
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