Oh humidity. How our hair loathes you, but how our plants love you. Read on to find the happy medium in your home that will keep your plants and your hair content.
What is humidity?
Humidity is essentially the amount of water vapor in the air. There are three primary measurements of humidity: absolute, relative and specific. Typically, when we hear about humidity, say on the weather or in reference to our hair struggles, we are referencing relative humidity. Relative humidity is normally expressed as a percentage; a higher percentage means that the air-water mixture is more humid.
You know how when it’s really hot outside and it’s also “sticky”? Like the air feels heavy? That’s relative humidity. It feels sticky and heavy to us because the amount of water vapor in the air (more water vapor in the air = higher humidity) actually hinders the evaporation of sweat from our skin. That’s why it seems that we start sweating profusely by just walking out the door in high humidity.
Why is humidity important for plants?
Plants don’t sweat quite like we do, but they do perspire. You see, just like us, plants have pores, called stoma or stomata, in the epidermis of leaves, stems, and other organs, that facilitates gas exchange for important processes such as transpiration and photosynthesis.
Transpiration is the process of water movement through a plant and its eventual evaporation from leaves, stems and flowers. Plants also inhale carbon dioxide through the stoma in their leaves to use during photosynthesis. When the stoma open to take in carbon dioxide, some of the moisture in the leaf can escape.
When the air is dry, it causes plants to transpire moisture much more rapidly than when the air is humid. Water in the leaves evaporates quickly into air and this causes the plant to lose moisture at a rapid rate. In order not to lose more water to the air, the plant will almost completely close its stoma, which also reduces the intake of carbon dioxide. Without a constant supply of carbon dioxide, photo can’t synthesize and the plant cells begin to die. This results in the plant looking tired, floppy and sick.
When plants have the right humidity, they live their best life. They can open their stoma completely and breath (i.e. exchange gas) deeply without excessive water loss. When the air is humid, there is little water lost from the leaf during essential plant processes like photosynthesis and transpiration.
Is there a “right” humidity?
The humidity level in an average home is at or below 30 percent. Most plants, including cacti and succulents, prefer humidity levels of 40 percent or higher. Most tropical plants require 60 percent humidity or more. In our experience, a happy medium for plants and people in a home is a humidity of at or around 50 percent.
It is not necessary to measure your humidity exactly, your plants will likely tell you if they want more by looking limp and tired. However, if you are concerned about getting the humidity just right, there are a number of inexpensive, reliable hygrometers available online. Here’s the one we use.
How do I provide humidity for my plants?
Providing humidity for plants is actually quite simple and easy. There are a number of ways you can give your plants the humidity they need:
Keep plants in a humid room in your home, like the bathroom. Check out our recent article on the subject.
Make a humidity tray.
Use a humidifier. You can also place bowls of water over your HVAC vents if you don’t want to shell out for a humidifier, though it is slightly less effective.
Mist your plants. Be aware this will only raise the humidity around the plant temporarily.
Huddle your plants. Read more on Brooklyn Homestead.
What plants need humidity?
Most plants need humid air in order to thrive, with air plants and tropical being the thirstiest. As a general rule, the thinner the leaf, the greater its need for humidity. Thick, leathery, or waxy leaves, or those covered with hair, fuzz or spines, are usually easy to keep happy even with dry air.
What are some of your favorite plants that are hungry for humidity? Share with us in the comments below.