Question: My houseplants often have weak stems, with their leaves too far apart on the stems. They just look ugly and lanky. Is that caused by the wrong kind of plant food, or too much water, or what?

Answer: Both of those could contribute. Using too much nitrogen could cause stretched growth, as could excessive water. By far the most common cause, however, is inadequate light. Plants’ cells elongate when they’re exposed to darkness. That’s why plants will stretch out of shadows toward a light source. When they’re in generally dark conditions, all of the cells will elongate that way, resulting in weak, spindly growth.