Plant Doctor: How Plants Increase Humidity in Buildings

We’ve all heard about it, but have you ever wondered how plants increase humidity in buildings?

One of the many selling points for interior plants is their ability to increase humidity. Depending on the number of plants in a space, increased levels of humidity may be quite noticeable and very welcoming in the dead of winter! This is good news as air inside buildings is typically dry, even when warm.

What’s the problem with dry air? Dry air contributes to skin irritations and itchy eyes. Breathing dry air can cause respiratory ailments such as asthma, bronchitis, nose bleeds and overall dehydration.

Dry air can also lead to increased static electricity, leading to more mild shocks when touching metal. Finally, dry air can make the air feel cooler. For example, a temperature of 75 F with 20% humidity will feel similar in comfort to a temperature of 70 F and 80% humidity. With everyone wanting to reduce their heating bills and carbon footprint, higher humidity can have a profound impact in winter.

How does a plant increase humidity? Like humans, plants sweat a lot! Most of the water a plant absorbs through the roots travels up the plant and is eventually lost as water vapor through tiny holes in the leaves. This process is called transpiration. In fact, most plants lose 90% or more of their water through transpiration (a fully grown tree can easily lose several hundred gallons of water in a single day from transpiration). This evaporation is what helps pull water from the roots all the way to the leaf tips.

Think of plants as natural humidifiers this winter!

Green Side Up,

Senior Horticulturist, Matt Kostelnick

Do you have a question for our in-house horticulturist Matt? Click here to ask the Plant Doctor a question.