If your houseplants look a little sickly, don't fret. They likely just have the season change blahs. Their unsightly appearance probably stems from a number of different conditions all working together over the change in season.
Houseplants are tropical plants.
They prefer a growing environment of high humidity and warm, non-fluctuating temperatures. They also prefer even soil moisture. Their leaf tips can turn brown, they can develop leaf spots and sometimes their leaves turn yellow. Here are some conditions that might lead to an unhealthy appearing houseplant along with some suggestions for good plant care. If plants are located near heating vents, they can develop leaf spots and brown tips.