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Can You Use a Diffuser as a Humidifier for Plants

Can You Use a Diffuser as a Humidifier for Plants?

Plants of all types are a go-to addition to home decor. Plants add color and depth to a home’s scenery while being an outlet and hobby to care for. There are many different species of little green friends that can require vastly different levels of care, particularly in the humidity they need.

Some species look their best in humid environments, while others thrive in dry heat. Introducing supplemental humidity may be necessary. Some friends only have a diffuser at home. So, can you use a diffuser as a humidifier for plants? The short answer is yes!

Humidifier vs. Diffuser for plants

Humidifier vs. Diffuser for plants

Although they share many similarities, there are a few differences between a humidifier and a diffuser. Knowing the differences is vital to help you make the best decision to care for your plants. 


Simply put, a humidifier’s primary function is to put more moisture into the air. They accomplish this through steam, ultrasonic, and evaporation methods. Available in both cold and warm veils of mist, humidifiers are most commonly associated with preventing dryness in different parts of the body. 

Due to the designed therapeutic purpose of a humidifier, they generally will put out more humidity than a diffuser, hence the name. It will increase the humidity more quickly, which is great for plants that need high humidity.


Diffusers, found in many health and wellness stores, are most commonly associated with aromatherapy. They use ultrasonic technology to push essential oils and water into the air in the form of a fine mist. However, essential oils are not critical for the function of a diffuser as they can be run without them, utilizing only water. 

Unlike humidifiers, they are designed for essential oils, emitting a smaller amount of mist. This would not be the ideal choice to increase the overall humidity level or for the same therapeutic benefits of a humidifier. A diffuser will not drastically increase the general humidity level in an entire residence. 

Both products put moisture into the air; the difference lies in their designed purpose and the amount of moisture they emit. If you choose a diffuser, pay attention to the size of the area you are placing it, there will be more on this further down. 

Why Do Plants Need Humidity?

Not all plants require high humidity, but it is crucial to the overall health of some. Plants native to dry climates, such as cacti and succulents, do not require much moisture. If you want the least amount of care possible, these would be the winning choices. 

Tropical plants can require extremely high humidity levels, no surprise considering where they originate. For some species, humidity levels as high as 90% are the norm. But why is this so important?

An essential function of humidity in plants is photosynthesis, the process plant life uses to convert sunlight into usable chemical energy. Lack of water causes a plant’s stomata to close, prohibiting the absorption of CO2, a necessary element for photosynthesis. In essence, CO2 absorption is more important than high levels of light. 

Plants produce oxygen, and humidifier help maintain the process of photosynthesis. That’s why we say humidifiers can increase oxygen indirectly.

Optimal light levels are important, but keeping stomata open and ready to absorb CO2 is far more crucial. Open stomata allow photosynthesis to take place even in low-light conditions. Closed stomata and high light levels will not do the plant any good. 

Stomata closure does not only stop photosynthesis. Like humans sweat, plants use evaporation to cool themselves on a hot summer day. The closing of stomata prevents the plant from shedding heat, inevitably causing an increase in temperature, which can be harmful or fatal for the plant. 

An increase of moisture in the air surrounding a plant will reduce the amount of evaporation necessary for cooling. Think in terms of a lawn being watered in the morning before the high mid-day heat of summer. The water on the grass prevents mass-evaporation and assists in cooling the grass. 

First, research the optimal level of humidity for your chosen plant, then utilize a humidity device to ensure this level is maintained. This will keep the stomata open and allow your plant to feed and stay cool. 

Humidifier for Plants

humidifier for plants

If you have several tropical natured plants scattered throughout the house and seek an optimal humidity level for your overall wellness, a humidifier is a good choice. Optimal levels for personal health are said to be between 30%-50%. The use of a humidifier will ensure your home stays at this level.

However, many plant species require levels far above the 30%-50% range. Because the moisture produced by a humidifier is difficult to contain, it may not be the best choice for the directed saturation of one plant. After all, no one wants a moist couch!

Diffuser for Plants

diffuser for plants

Diffusers emit a much smaller amount of moisture than humidifiers, and they can only humidify the small space in which the unit is located. Generally, the mist put off by a diffuser is not warm, making it safe for more direct contact with plants. 

Many people enjoy the relaxation benefits of aromatherapy and thus have a diffuser readily available. So, can a diffuser be used as a humidifier? If you only have one plant that requires a higher humidity level, a diffuser is a great option to utilize in this space. 

An Added Benefit of a Diffuser

So do you lose the ability to diffuse essential oils when using the diffuser to maintain a healthy plant? No! In fact, there are added benefits to using essential oils near plants.

Many essential oils are derived from parts of plants. Tea tree oil, abundantly common in aromatherapy, helps fight off insects from invading and feeding on plants. Cinnamon oil has added antifungal benefits and can prevent the growth of harmful fungi that can be a danger to your plant pet. 

It is best to research the effects of any particular oil before exposing your plants to them. They should also be used in moderation as plants can counteract the oils. Plants work to filter the air and thus can filter your essential oils. 

How To Use a Diffuser for Plants

As discussed, diffusers have much smaller output than a humidifier. Remember that location is key if you choose to use a diffuser to regulate plant humidity levels. 

It would be best to position the diffuser in a closed space, such as a plant corner, giving the moisture less space to escape. It is important to place the unit close to the plant while maximizing the amount of surface space of the plant covered by the mist. 

Other Ways to Increase Humidity for plants

If you do not want to use a diffuser or humidifier, several other options are available to you. Plants release moisture through a process called transpiration. Grouping plants together can create a more humid microclimate for them to thrive.

A simple and aesthetically pleasing way to increase humidity for plants is by using a pebble tray. Fill a tray with small pebbles and fill that tray up with water about halfway up the pebbles. Now set your plant pot on top of the stones. Use caution not to submerge the pot in water. Allowing plants to rest in water can promote root rot. 

To increase humidity with plants, grab a cheap spray bottle from the grocery store for an overly simple way. Fill the bottle with clean water, and then simply mist the leaves of your plants. The mist will mimic the effects of a humid environment, providing the same benefits. 

Final Thoughts

When appropriately used, a diffuser can help keep your plant healthy by optimizing humidity levels and providing the added benefits of essential oils exposure. In turn, ensuring your plant stays happy and healthy, even if it’s not native to your local area.

Additionally, a diffuser provides a more cost-effective method of humidity control than a humidifier if your plants don’t need too much moisture to add. So head down to your local health and wellness shop and pick up a diffuser. While you’re at it, grab a few essential oils that will benefit your plant.

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested more than 150 products in person, including humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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