Many houseplants are tropical plants. When considering how to best care for these plants, you should consider their original. Plants in tropical climates often grow beneath a canopy of trees, which filters sunlight so the plants receive diffused light, and tropical climates tend to be humid. Although your home environment might not exactly match this, you can make adjustments to provide a more suitable climate.
Place your tropical plant pots in trays filled with gravel. By pouring water in with the gravel, the humidity around the plant will remain more suitably humid for these plants, as suggested by the Texas Agriculture extension service. They also advise grouping plants together, if you have more than one, so the humidity levels stay stable. Another thing you can do it mist tropical plants occasionally (at least once a week) with a spray bottle.
Keep your tropical plants in areas where they will receive light, but not too close to windows. Sunlight through windows can scorch leaves; many tropical plants need light, but not direct sunlight (this can vary--always check the instructions that may come with the plant when you buy it).
Fertilize tropical plants during the usual growing season, which is from early spring until early fall. There is usually no need to fertilize houseplants during the winter months. You can use general, balanced plant formulas in liquid or granular form; or, more easily, you can use a fertilizer stake that you simply stick into the soil. These release nutrients each time you water, and last about three months.
Water tropical plants at least once a week until water comes out the bottom holes of each pot. Watering needs for different plants vary. In general, keep them moist but not constantly wet and do water them deeply. Shallow watering will not reach the roots and your plants will suffer. Empty the saucer beneath the pot each time to remove contaminants (salts) so they are not reabsorbed by the plant.
Keep your house warm enough for your tropical plants. According to the Caringforhouseplants website, you should keep it between 60 to 80 degrees Fahrenheit.