If you kept your indoor plants outside so they could enjoy our tropical summer or just keep them inside year-round, most of them are going to need some serious attention by now.
These tips can help you keep indoor tropical plants like snake plant, peace lily, spider plant, philodendron, schefflera and anthurium healthy and happy. They also apply to palms, ferns and flowering tropicals that you overwintered indoors, including tropical hibiscus, bougainvillea, mandevilla, pelargonium (commonly called geranium) and even gerbera daisy. You can follow a similar regimen with cacti and succulents, modifying as necessary to account for their special needs.
Tropical plants that are primarily grown for foliage should already be in windows that provide the appropriate light for the plant. You need to meet your plants' light needs. Snake plants, for example, do not do well in the bright morning or afternoon sun. Neither do peace lilies or philodendrons. Make sure you provide adequate water for these plants as well.
Some flowering tropicals that are being overwintered indoors lose their leaves when brought inside. These include tropical hibiscus and bougainvillea. Others, like mandevilla and pelargonium, keep their leaves. Plants that have lost their leaves should have already been stashed in a cool, dark room. In contrast, I have had good luck keeping my still-green plants like mandevilla, pelargoniums and gerbera daisies in a cool room with an LCD ceiling light on. I don't use a plant light or even a full-spectrum bulb.
Both leafless and still-leafy flowering tropicals should be watered intermittently and sparingly. The goal with these plants is to keep them alive but allow them to go dormant. While the plants are dormant, too much water will simply result in rotting roots. If leaves start drooping, you'll know the plant needs water. Once freezing weather is no longer in the forecast, you can start moving these plants outside to a sheltered and shaded location at first. Begin watering more copiously and frequently as the temperature warms up and the plants leaf out. Tropicals that have lost their leaves over the winter may be slow to wake up, but should eventually thrive.
There's still time - if you haven't yet done so - to clean your plants up. Debris like dead leaves can be picked out of the pot and off the plant. If you can tell which branches are dead, these can be pruned off. Search for bug infestations and note dusty leaves. You don't necessarily need pesticides for the bugs. Pull double duty by washing off the bugs and the dusty leaves in the shower or by using the sprayer in your kitchen sink (unless the leaves are the fuzzy sort). Wipe the leaves dry with a soft cloth. If the plant won't fit in your shower, you can wipe the leaves with a clean, damp cloth. Note that some bugs, like sow bugs, are harmless and eat dead vegetation. You don't have to get rid of every creepy-crawly. However, it's best to do some research, since a number of other bugs like aphids, mealybugs and whiteflies multiply quickly and are harmful to the plants.
Do some research to see whether your plants should be repotted. Some plants, like snake plant and bougainvillea, like to be pot-bound and grow happily in crowded pots. Other plants may be more likely to respond well to repotting. The best rule of thumb if you are repotting is to choose a pot the next size up from the current one. Use good-quality potting soil to assure proper drainage. You don't need to fertilize separately - just make sure your potting soil has slow-release fertilizer in it. The latest newsflash is you don't need to put stones or pieces of broken pots over the hole in the bottom of a pot to help with drainage. Just make sure there is drainage out of the pot, and don't let the pot stand in water. Overwatering kills more plants than under-watering. Repotting is best at the time the plant is going to put forth growth, so do some research on that as well.
The Missouri Botanical Garden in St. Louis has a great website for identifying plants and learning about their care. Go to www.mobot.org and follow the links to the plant files. The Missouri Botanical Garden also has a horticulture line you can call for advice, similar to the Central Missouri Master Gardener info-line that is staffed during the summer in Jefferson City.