As part of our feature series, Plant Parent Basics, in this article you will learn the optimal humidity that your house plants need, and how to provide it for them.
What is humidity and why is it important to plants?
You know how when it’s really hot outside and it’s also “sticky”? Like the air feels heavy? That’s 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.
Plants don’t sweat quite like we do, but they do perspire. You can learn more about the science of plant perspiration in our article devoted just to humidity. All you need to know for this article is that when plants have the right humidity, they live their best life.
What plants need more humidity and which plants need less?
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 or less (hint: keep reading to the next sections). 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.
Generally, house plants need less warm air and more moist air than you think. Typically, papery or thin leaves, like those of a fern or air plant, need more humidity than thick ones, like those of a fiddle-leaf fig. If you are wanting to grow more than succulents and cacti in your home, we suggest you try one the following methods to increase the humidity in your home to keep you plants happy and thriving.
What can I do to provide humidity for my plants that need it?
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. Do not mist your plants at night, as this can cause leaf spotting and damage.
Huddle your plants. Read more on Brooklyn Homestead.
How can I tell if my plant is getting too much humidity? Not enough humidity?
House plants are quite good at communicating their needs to you. Your plant may display one or more of the following signs if it is getting too much humidity:
Leaf tips become shriveled, brown and/or crusty
Leaf edges turn yellow; wilting may occur
Buds and flowers shrivel. and fall
Leaves fall if plant is very sensitive to dry air (for example, many ficus species, such as fiddle leaf fig and rubber tree); may begin to drop their leaves once you turn on the heat in the winter.
Your plant may display one or more of the following signs if it is not getting enough humidity:
Patches of gray mold on leaves
Patches of rot on leaves or stems, particularly common on cacti and succulents
Flowers covered in gray mold