The key to healthy plant life is hearty soil—and fortunately, the nourishing earth that sits underneath your plants is easier to maintain than the greenery itself. Here’s how to check if it needs replacing:
• If mold or a fungus grows on the soil’s surface (this happens when soil is always moist), repot the plant entirely. Same goes for soil that seconds as a cat’s litter box, as “the soil absorbs a lot of ammonia, which can kill a plant,” says Ellen Zachos, a New York Botanical Garden instructor.
• Has the plant outgrown its container? Replace the soil entirely. An easy way to tell when the pot is too small is “the roots grow out of the drainage hole,” says Zachos.
• Over time, repeated watering leaches nutrients out of the soil. If you don’t use fertilizer, do your houseplants a favor a change the soil every two years. If your plant has lived in its current pot for years and already reached its maximum size, you’ll only have to replace the top one or two inches.