House plants that basked in the summer sunlight and fresh air, and the occasional soaking rain, are now housebound. They've come in from the cold - like the rest of us.

At the first sniff of cooler weather, most of us dragged plants indoors for the night and then spent a few weeks shuttling them in and out on nice days. Finally, it became a hassle and the plants were moved to their winter home, probably a spare bedroom.

The contrast is like leaving the tropical rain forest and moving to Death Valley. Plants may experience some transplant shock and look bedraggled. It's also natural for many plants to take a long winter's nap, slowing or stopping their growth. Leaves may drop, too, but usually it's no cause for alarm. Plants need their rest, too.

When plants aren't growing, fertilizing and watering can be reduced. And face it, that's a good thing because (raise your hand) you may forget to water from time to time. In March or April, when plants show signs of emerging growth, start fertilizing again.

The biggest bugaboo is lack of humidity. Indoor air can be drying, particularly with heat pumping out of vents. Just as lack of humidity can rob our skin of moisture and make us feel dry and itchy, plants can get dehydrated, too. Lucky for us, we can slather ourselves with lotion. House plants prefer daytime temperatures from 65 to 75 F and night temps at 60 to 65 F.

A humidifier, obviously, can increase indoor humidity. Remember to follow manufacturer's directions on frequency of cleaning. Another technique is to group plants closer together to increase humidity. Transpiration of foliage and evaporation of moisture from the soil adds humidity to the air. Fill saucers with pebbles or aquarium gravel, then cover with water and set them amongst the plants. Or place a layer of pebbles in a waterproof tray, cover pebbles with water and place pots on top of pebbles. Just remember to keep the pebbles covered with water.

Use the index finger approach to watering plants. Poke your finger about an inch down into the potting soil. Feels dry? Then water. Or pick up the plant and if the pot feels light, it probably needs water. Smaller pots can be set in a sink or tub with a few inches of water. They'll soak up water through their drainage holes. Empty the sink or tub and let the plants drain. Otherwise, water at the roots; try not to wet the foliage.

Root rot and wilting are signs of overwatering. Lift plant from pot and check the roots. Healthy roots are firm and white. Underwatering puts plants under stress.

Empty water saucers to prevent plants standing in water. Spritzing plants with a mister may make you feel better, but you'd have to spritz all the live-long day to increase indoor humidity levels. On the positive side, spritzing can discourage spider mites. Ferns need moist (not wet) soil to thrive and may need more frequent drinks. Succulents are at the other extreme, preferring desert-like conditions before watering.

I often bring in potted plants like caladiums at the end of summer to extend my enjoyment. Eventually the plants go dormant. Reduce watering and stop fertilizing. When the plant has dropped its leaves and died back, remove the spent foliage, dig up the tubers and let them dry out for a week. Then store them in a brown paper bag or chopped-off leg from a pair of panty hose, in a cool, dry location. You can replant in the spring.

Plants also require a good source of indirect lighting, so make sure your windows are clean. In winter months, light intensity changes and you may need to make some adjustments. Most plants will adapt, but flicking on the light switch every now and again can't hurt.

Keep foliage dusted. Clean foliage absorbs humidity better and dusting is a good way to check for insect or disease problems. Mealy bugs, spider mites, aphids and whiteflies can decimate a house plant collection. Always quarantine a new plant for time to make sure you haven't brought home any stowaways. Look for telltale signs of insects: mealy bugs, aphids and scale leave a sticky or glistening "honeydew" on foliage, as well as on the area near the plant. Lightly swab foliage with a cotton ball dipped in alcohol.

Spider mites cause leaves to curl, and mites leave behind "dirt" or excrement and exoskeletons on the underside of leaves; foliage may have a webbed appearance on top. Discard heavily infested plants.