Root rot, on the other hand, is one problem that isn’t as easy to recover from—which makes early detection essential. Here are some pro tips on spotting, treating, and preventing this leading cause of houseplant death. The roots are like the engine of a plant: They keep things running and fuel all the foliage you see above the surface. So when they die off, the rest of the plant tends to do the same. “Plants need oxygen to photosynthesize and to convert food into energy,” Debbie Neese, a horticulture expert at Lively Root, explains to mbg. “If oxygen isn’t present around the root system, the root cells aren’t able to produce a key molecule for saving and transporting energy in cells. The roots start to die and disable nutrient uptake, which then leads to plant death.” If small fungus gnats have settled around your plant, it’s another bad sign. “That indicates that the soil is too moist and could show some further root issues if steps aren’t taken immediately,” Neese says. The last clue to look out for—or rather, to smell for—is a sour, rotting eggy odor emanating from your plant. If you notice any of these signs, it’s time to take your plant out of its pot and analyze its roots up close. “If the roots are brown or black and soft or mushy instead of a healthy, creamy white, it indicates root rot,” says Neese. Once you diagnose root rot, it’s time to do some damage control. Here’s Neese’s procedure for saving plants that have root rot: If you’re prone to overwatering, Neese says that using a moisture meter might help you break the habit. These small, inexpensive gadgets are the plant world’s version of a meat thermometer: You stick them in soil to gauge whether or not it’s ready to be watered. Making sure that your plant has proper drainage is also key. If you have a decorative pot that doesn’t have a hole in it, drill one yourself, or place your plant in a smaller plastic pot that does have a hole, and nestle that pot into the larger decorative one. Emma received her B.A. in Environmental Science & Policy with a specialty in environmental communications from Duke University. In addition to penning over 1,000 mbg articles on topics from the water crisis in California to the rise of urban beekeeping, her work has appeared on Grist, Bloomberg News, Bustle, and Forbes. She’s spoken about the intersection of self-care and sustainability on podcasts and live events alongside environmental thought leaders like Marci Zaroff, Gay Browne, and Summer Rayne Oakes.