You lovingly water your plants on an appropriate basis, you have them in the perfect lighting and there’s not a bug anywhere to be seen. So why do your plants still develop crispy, brown leaf edges or look a little shriveled and droopy? Low humidity is likely to blame.
There are many ways to go about raising your home’s humidity to plant-friendly levels:
- Use a humidifier
- Make a pebble tray
- Move your plants to naturally humid rooms
- Frequent misting
- Create a plant grouping
- A terrarium or plant cabinet
- Wiping down the leaves with a damp cloth
Not all humidity strategies are appropriate for all plants, so you have to use the one(s) that are appropriate for your plant’s specific needs.
In this article, you’ll learn more about how to increase humidity for plants using the methods listed above. You’ll also discover why houseplants need extra humidity in the first place and the answers to some common questions.
Let’s dive in and get your plants some much-needed moisture!
Why Do Plants Need Humidity?
For optimal growth, plants need to maintain a delicate balance of taking in water/nutrients and releasing oxygen/excess moisture. This process is called transpiration, and it occurs in microscopic openings in the leaves called stomata. Think of stomata as the plant’s pores- they allow gases and moisture to get in and out, and they can also open and close, like human pores.
Plants absorb most of their water through their roots, but according to Purdue University, they can absorb water to a limited degree through the stomata. In low humidity conditions, plants close their stomata to decrease the amount of moisture lost through transpiration. This then slows down moisture/nutrient absorption and photosynthesis.
In higher humidity, the stomata are open, allowing for optimal nutrient uptake and sugar production.
Most popular houseplants are tropical, meaning that they naturally grow in warm, humid areas of the earth. These plants have adapted their transpiration and photosynthesis (food production) processes to work best in high humidity.
Relative humidity in the tropics can easily be 60% to 80%, and many homes are somewhere in the 30% to 40% range. When the air is dry, your plants can lose too much moisture through their leaves, leading to dehydrated, limp leaves.
The good news: You don’t have to raise your home’s humidity levels to 80%! In most cases, the ideal humidity for plants is typically between 40% to 60%.
Signs Your Plant Needs More Humidity
In low humidity conditions, plant cells can get dried out and lose their normally-rigid cell wall structure.
If you spot any of these problems with your plants, it’s a good sign that they need more humidity:
- Crispy or brown leaf edges
- Leaf tips and edge curling downward
- Slow growth
- Wilting leaves or stems
- Wrinkly, shriveled leaves
- Leaves that partially unfurl but then seem to get “stuck”
- Flowering plants may drop their blooms during the bud stage
- Misshapen leaves
How to Create Humidity for Plants
So now you’ve seen why humidity is pretty important for the health and appearance of your plants. Fortunately, there are plenty of ways to give your houseplants the moisture boost they need.
Some of these methods produce more humidity than others, so which ones will work best for you depends on your specific plants. Let’s get down to the details:
1. Use a Humidifier
Running a humidifier is the most effective and reliable way to get your plants the water vapor they crave. Since it produces a continuous, fine mist, it most closely resembles the natural humidity in tropical regions.
If you have several humidity-loving plants grouped together in one room, a humidifier is perfect for supplying everyone’s needs at once.
And it’s easy- just fill it up, turn it on and you’re good to go for many hours. Plus, your own skin and hair can benefit from the extra air moisture!
There are three main types of humidifiers on the market:
- Ultrasonic (by far the most common)
- Warm mist
- Evaporative (available, but few and far between)
Any of these humidifier types work equally well for plants. Use clean, preferably filtered water in your humidifier to prevent mineral build-up. This is particularly important for ultrasonic models- they tend to generate mineral dust, and you don’t want to be breathing that in.
2. Make a Pebble Tray
With a pebble tray, your plant sits atop water and small stones, and the humidification process is simple:
- The water is underneath your plant, and as it evaporates it rises, humidifying the air around your plant.
- The tops of the pebbles are higher than the water line, protecting your plant from soil saturation and root disease.
Choose a shallow dish that’s about the same size or a little larger than your plant’s leaf canopy, and fill it with pebbles or small river stones. Make the surface of the pebbles as smooth as possible.
Fill the tray with enough water to come just below the pebbles’ top. Set your plant on the pebbles, making sure it’s stable and won’t tip over too easily.
Refill the water when it starts to get low, and do a total water change about every 7 days. If you let the water stagnate, it may start to smell bad or attract insects.
3. Move Your Plant to a Naturally Humid Room
Rooms that frequently have running water are already higher in humidity than other areas of your home. The most common examples are:
- Laundry room
The lighting in these rooms has the greatest influence on which plants will happily grow there. If you have a lot of natural light coming in, almost any plant should do fine. But if your natural lighting is on the lower side, these green friends should still do well:
- English ivy
4. Frequent Misting
Misting your plants helps temporarily raise the humidity in the immediate area, but this is a divisive topic among plant lovers.
Some people feel that misting introduces too much moisture and isn’t effective since it only generates humidity for a short time. Others believe regular misting helps their plants look their best and produces adequate humidity.
I tend to be in the latter group. I’ve never run into a problem with my plants, but I’ve also been careful to follow a few guidelines:
- If you can at all help it, don’t mist your plants in the late afternoon or evening. The nighttime darkness and cooler temperatures slow down evaporation and absorption, leading to pooled water and the potential for mildew/fungus.
- Instead, aim to do your misting in the morning or early afternoon hours, when the sunlight can help keep the humidity-creating process moving along.
- Your goal here is to increase air humidity, not give your plants a shower. Use a bottle that produces a fine mist rather than large droplets, and make sure each leaf gets just a light spray.
This strategy is both easy and quick, but it’s not appropriate for every plant. Plants with textured leaves trap moisture droplets on the leaf surface rather than losing them to evaporation or absorbing the moisture through their stomata. Because of this, these plant varieties are very prone to developing leaf spots or mildew.
These are some plants you should not mist:
- African violets
- Philodendron micans
- Philodendron gloriosum
- Anthurium clarinervium
- Alocasia Black Velvet
- Fiddle leaf fig
In these cases, skip the misting altogether and use another method for increasing humidity.
5. Create a Plant Grouping
Besides absorbing moisture, plants also release moisture through transpiration. When you move plants close to each other, you can make a tiny pocket of humidity for all the plants to share.
The most effective way to harness this natural process is to place smaller plants near larger ones. The larger plants transpire a greater amount of moisture that the smaller plants can then readily absorb.
But even if they’re roughly the same size, plants can still benefit from moisture-sharing with their friends.
6. Consider a Terrarium or Plant Cabinet
Since it’s a partially or totally closed environment, terrariums and plant cabinets naturally trap moisture and create a humid microclimate. They’re basically indoor miniature greenhouses!
Terrariums work best for small plants. These are some popular choices:
- Miniature ivy
- Polka dot plant
- Nerve plant
This video from Garden Answer does a great job of outlining how to build an adorable open terrarium:
For larger plants, a plant cabinet can be a great option. This glass cabinet from Picket Fence allows you to display your plants while giving them the humidity they need at the same time.
A cabinet will naturally become humid as plants transpire moisture. But for an even greater moisture boost, you can add a dish of water to evaporate.
7. Wipe Down Leaves With a Damp Cloth
Dampen a lint-free cloth with clean water, and gently wipe off each of your plant’s leaves. Cotton t-shirt material works perfectly for this purpose, so if you’ve got an old t-shirt that you don’t wear anymore lying around, cut it up and use it for your houseplants!
Wiping your plant’s leaves down regularly also removes the dust that so quickly accumulates on houseplants. So not only will your plants look better and cleaner, but they’ll also be able to photosynthesize food more easily without that layer of dust in the way.
Bonus: Consider Growing Your Plants in Water
Some plants can thrive in nothing but a bottle or vase of water or in a water-based growing medium like LECA or pebbles. When you grow your plants in water, you automatically meet all their moisture/humidity needs and greatly reduce the chances of plant disease (like root rot) and pests.
While it’s not appropriate for every plant, water growing works well for plants that have high humidity needs. Here are some examples of plants that grow happily in water:
- English ivy
- Tradescantia zebrina (also called inch plant, Wandering Dude, spiderwort)
- Trailing philodendron (Micans, Brasil, heartleaf)
- African violet
- Chinese money plant
Moving an established plant from soil into water can have a high failure rate, so your best bet is to take some cuttings off your plant and root those in water.
Plants That Do Not Require Extra Humidity
All plants need moisture, but not all of them are capable of absorbing it through their leaves.
Plants that are native to dry, desert climates have fewer and smaller stomata that typically only open at night. These plants use their stomata primarily for absorbing carbon dioxide, but they also use them to “exhale” oxygen and water.
These plants include:
- Aloe vera
Since they don’t absorb moisture through their leaves, water droplets just collect and stagnate. This can lead to mildew or fungal growth, affecting both the look and health of your plant.
So make sure your desert plants are away from the humidifier or other humidity source. Instead, keep them in a drier room with good airflow.
Frequently Asked Questions about How to Increase Humidity for Plants
Most houseplants will at least greatly appreciate you adding extra moisture to the air, and some absolutely require it. A humidifier is the most effective method, but if you want to avoid using electricity, there are plenty of other passive humidifying methods that work, too.
Do you have any more questions about how to increase humidity for plants? Are there any other effective methods that you’d add to the list? We can all learn from each other’s thoughts and experiences, so please share in the comments!