Humidity Matters: Why Your Houseplants Crave Moist Air
By Justin Hancock for Costa Farms
When it comes to houseplant care, light and water get all the attention—but relative humidity is just as crucial. Most tropical plants evolved in lush, humid environments, and the dry air inside our homes (especially during winter or in air-conditioned spaces) can leave them struggling.
Why Relative Humidity Matters
Relative humidity (RH) is the amount of moisture in the air compared to how much it could hold at a given temperature. For most tropical houseplants, ideal RH levels are over about 50 percent. When humidity drops too low, plants lose moisture faster than they can absorb it, leading to crispy leaf edges, browning tips, and stalled growth.
How to Measure It
You don’t need fancy gear to monitor humidity—just grab a digital hygrometer. These inexpensive tools give you a quick read on your room’s RH levels and help you track changes throughout the day. Place it near your plants (not next to a vent or window) for the most accurate reading.
How to Improve Humidity
If your RH is consistently low, here are two effective ways to boost it:
Humidifiers: These are the gold standard. A cool-mist humidifier placed near your plants can dramatically improve air moisture. Look for models with adjustable settings and easy-to-clean tanks.
Cloche or Plant Cases: These mini greenhouses trap humidity around your plants. They’re especially useful for small tropicals or humidity-loving species like ferns and calatheas. Just make sure there’s some airflow to prevent mold.
Skip the Misting
Misting might feel like a quick fix, but it’s mostly a myth. The humidity bump from misting lasts only minutes, and frequent misting can encourage fungal issues. If you enjoy misting for the ritual, go for it—but don’t rely on it as your primary humidity strategy.
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Even the most attentive plant parents can find themselves with a houseplant dropping leaves and wondering what went wrong. With a few thoughtful tweaks, you can nurse them back to good health. Click here to read an interesting, helpful article.
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