with my house plants it has always been one of two things.... aside from figuring out a good watering/ fertilizing schedule (too much can do it) but too much DIRECT sunlight, especially afternoon sun... or not enough sun, depending on waht the plant calls for ie. peace lillies like shade, mine turned brown because the sunlight that did hit it burned the leaves and made it wilt aloe likes the hot afternoon sun, before it turned brown when it didnt get enough in my experiance plants that say "like bright light" if you have an open area that gets bright in the daytime they will do great... direct sun is not always key:) also the morning sun is much less HOT so i have some ivy that thrives in the front windows... so if i blabbed on... just typing as i was thinking :)