Overwatering Isn’t Just Bad For Your Plants, It’s Bad for Your Health, Too

updated Jun 14, 2021
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If your houseplant looks brown or droopy, it’s only natural to assume it needs more of something: more attention, more sunlight, more water. But, just like caring for an animal or human, caring for plants is about finding the right balance. More water, for example, might be exactly the opposite of what your houseplants need — excessive moisture can essentially suffocate a plant, even leading to its death. 

But overwatering your plants isn’t only harmful to the plants themselves; too-moist plants can actually negatively impact the plant parent’s health, too. According to Robert Eitches, an allergist and immunologist with Tower Allergy in Los Angeles, over-watering indoor plants increases the humidity in your home, which can potentially cause some unwanted effects in your body. 

Read more: Stop Trying to Make Air-Purifying Plants Happen

For one thing, too much moist heat in your space can create a breeding ground for dustmites. Here’s why you don’t want dust mites in your living space: “They eat human skin, they grow, they poop, and then the poop becomes airborne and can cause allergies and asthma,” says Eitches. 

Too much humidity in your plants themselves can also lead to mold growth in the soil and, eventually, in your home’s air. Breathing in mold particles can create nasal symptoms, stuffiness, itchy nose and eyes, or rarely, even severe chest symptoms. “Aspergillus, a type of mold, harbors itself in the lungs, and once it’s inside, it’s really hard to get out,” Eitches says. 

Credit: Joe Lingeman/Apartment Therapy

These over-watering risks bring up an important question: How do you know if you’re watering a plant too much? First, always follow watering instructions specific to the plants you’re caring for — most common indoor plants only require watering once a week or so, or even less. For example, you’ll want to water your fiddle leaf fig about once a week or every 10 days; but ZZ plants only need water about once every two weeks. As a rule of thumb for any plant, Eitches suggests aiming for mostly dry-to-the-touch soil. If the soil feels wet long after you’ve watered it, scale back — conditions are likely too moist.

It’s worth noting that running humidifiers in your home during the winter can have the same effect as over-watering your plants. Of course, if you’re sick in bed, it’s OK to run a humidifier, but in general Eitches recommends against them; instead, he suggests HEPA air filters. And if you have any control of humidity in your home, Eitches says right around 45 to 50 percent is a good level to aim for. Your respiratory tract will thank you!