If you’re a plant lover, you know that maintaining a healthy and thriving environment for your house plants can be a challenge. One of the key factors is maintaining optimal humidity levels. If the humidity level is too low in the short term your plants might develop brown tips and edges on its leaves. Whereas dry air in the long term will cause its health to suffer. But did you know that you can create your own DIY plant humidifier? From simple water trays to more elaborate setups, there are plenty of options to choose from. Which ones actually work? Read on to find out.
What humidity level do your indoor plants need?
In summer air contains more moisture, and in winter it has less moisture. If you don’t live in the tropics, a normal indoor humidity level is between 30-50% and might get up to 70% during humid weather. Any increase higher than that will only be temporary. If you consistently have humidity above 50% you are at risk of mold, mildew and fungal diseases.
Low humidity is a common problem during the winter months or in homes with central heating or air conditioning. Fortunately, there are many ways to increase indoor humidity levels. In fact, some of the easiest ways to create higher humidity involve items you may already have around the house. Unfortunately, most of these methods only boost humidity by 5-10%.
It’s not all bad news though. The quoted humidity level for tropical plants is usually the optimum level. It is intended for commercial growers in greenhouses or controlled environments. Your plants can survive at a lower humidity level than what it says on the label. They’ll even be happy and put on new growth, they just won’t be setting any growth records. In my office I have a calathea, peperomia, monstera, spider plant, string of pearls and epipremnum. The relative humidity is usually between 40-50% and they do just fine. Sure, they’d be really happy at 60% but I don’t like the idea of all my books and soft furnishings getting mildew.
So, how do you know what humidity level is right for your plants? The best thing you can do for your indoor plants is to purchase a hygrometer, which is a device that measures humidity. They are only a few dollars and a great investment to help you to monitor your plants’ living environment and learn what they like best.

DIY plant humidifier hacks that don’t work

Misting with a spray bottle
Misting your plants with a spray bottle is a popular DIY humidifier hack, but it isn’t an effective method. While misting is an easy way to provide a quick burst of moisture, it doesn’t necessarily increase the overall humidity in the air. In fact, misting too frequently can lead to overwatering and potentially harm your plants. Automatic misters can increase humidity but are best used outdoors or in greenhouses as they will wet everything around them.

Bowl of water
One of the simplest DIY plant humidifier hacks is using a tray of water. Simply fill a shallow dish with water and place it near your plants. As the water evaporates, it will increase the humidity in the air around your plants. This method will get you a small increase in humidity (up to 5%) but this is only in a very small area around the bowl. This method is not effective for larger plants or larger spaces. If you are going to use it you need to clean and refill the bowl regularly or it will turn into a slimy insect graveyard.

Pebble tray
Humidity trays are a minimally effective way to add moisture to the air around your indoor plants. To make a humidity tray, fill a shallow tray or dish with clean pebbles and add water until the water level is just below the top of the pebbles. Place your potted plant on top of the pebbles, making sure the bottom of the pot is not touching the water.
As the water evaporates, it will increase the humidity of the immediate area. It has an advantage over the bowl of water method because you can position the plant in that small increased humidity zone. Adding the pebbles creates an increased surface area for water to evaporate. This means it can get a slightly higher increase for your plants of up to 8% relative humidity. Clean and refill regularly or you know what will happen. Yep, slimy insect graveyard again.
DIY plant humidifier hacks that DO work
Clustering plants
The success of this strategy depends on a lot of different factors, most importantly the number of plants you cluster, and the combined surface area of the leaves of the plants. As the leaves transpire water evaporates from their surface, raising humidity in the immediate area. Transpiration is a fairly constant process which means that this increased humidity is maintained over time.
When all of the different factors are optimal it can get you a 10% increase in relative humidity in the immediate area. This isn’t a lot, but it really doesn’t take any effort to maintain and is a minimal risk to the health of your plants and other household members. If you have a lot of plants, this is one of the best ways to create a slightly more humid environment for them, so it’s worth trying it.

Humidity dome
If you only need to temporarily create a high humidity environment, such as when propagating plants or trying to revive a sick plant, this is ideal. There are lots of ways to create a humidity dome but all you really need is an airtight vessel that lets light in. This can be a clear plastic bag, glass bowl or plastic storage container. Water the plant then cover it with whatever airtight option you are using. That’s it. If you want a little bit of airflow you can use a hole punch or scissors to create small openings in the bag. Alternatively, place a small object under the edge of the bowl or plastic container to prop one side up.
Watch how you can repurpose duvet cover packaging as a humidity dome below.
Indoor greenhouse or terrarium
If you are serious about your indoor plants and can’t bear the thought of parting with the most moisture-loving varieties consider buying them a reptile enclosure, fish tank or fish tank cabinet to live in. This will act as a terrarium and if you are lucky will also have lights fitted.
You can make something similar using clear perspex. A fish tank needs to be strong thick glass to hold all the water. If you are only using it to replicate tropical environments for your plants then thinner and lighter plastic sheets will do exactly the same thing but are much cheaper.
There’s even some Ikea hacks that show you how to transform a glass cabinet into an indoor greenhouse complete with grow lights.



If your DIY skills don’t quite stretch this far you don’t need to worry. There are terrariums of all sizes and for all budgets readily available.
Cool mist humidifier vs warm mist humidifier
Another great way to increase indoor humidity is by using a humidifier. A cool mist humidifier is the most effective way to add extra humidity to the air, and they are relatively inexpensive and easy to use. You can also use a warm mist humidifier, which adds extra moisture to the air by releasing steam. However, it’s important to note that warm mist humidifiers should only be used in areas where there are no children or pets.
Cool mist humidifiers work by blowing air over a wet wick or filter, which then evaporates and creates a fine mist of water vapor. This mist is released into the air, increasing the overall humidity level. Cool mist humidifiers tend to use less electricity than warm mist humidifiers and can be more affordable to operate. One disadvantage of cool mist humidifiers is that they can be noisy when the fan is running, which can be distracting in some environments.
A cool mist humidifier DIY hack is to direct a fan over a wet sponge sitting in a bowl of water, or a hand towel suspended over a tray or bowl of water. The hand towel or sponge will continue to draw up water from the bowl as the fan evaporates it. You’ll just need to keep topping up the water.
Warm mist humidifiers work by heating water until it becomes steam and releases it into the air. Generally, they are quieter than cool mist humidifiers because they don’t require a fan to operate. Warm mist humidifiers can also be beneficial during winter. This is because they help to warm the air and add moisture at the same time. One of the disadvantages of warm mist humidifiers is that they can be expensive to operate, as they require more energy to heat the water.
THE ULTIMATE DIY PLANT HUMIDIFIER HACK
Wish you had an easy plant humidifier solution that can recognize when your plants need more humidity and instantly start adding more moisture to the air for them? That’s exactly what this hack does.
You need a humidity sensor that acts as an electrical switch, and your choice of cool mist or warm mist humidifier. To be on the safer side, we recommend a cool mist humidifier, and you’ll want to get the one with the largest water reservoir you can find. A 6.5L cool mist humidifier will last a couple of days before needing a refill. Or you can try a monster 20L cool mist humidifier that can last up to a week before refilling.
All you need to do is plug the humidifier into correct socket on the switch and plug the switch into the wall outlet. Set the lower humidity level for when you want the humidifier to turn on (e.g. 40%) and then the upper humidity level for when you want it to switch off (e.g. 55%). Then fill your humidifier reservoir and turn it on. The sensor switch will automatically turn it on and off to maintain the desired level of humid air in your space.
Yes, it takes a little investment, but this is the easiest way to ensure the health of your humidity-loving houseplants. The humidifier can add as much moisture to the air as needed to reach the desired humidity level so that you can grow happy healthy plants.
In a nutshell
Indoor plants are a great way to liven up your home, but they can be susceptible to low humidity. Winter months, when your heating system is in full swing, is when humidity is lowest. By using some of the tips mentioned above, you can easily increase the relative humidity in your home and create a more tropical environment for your humidity-loving plants. Don’t waste time and energy on ineffective humidifier hacks. Get yourself a hygrometer and test our recommendations out to find the best ones for your plants!

Still have questions?
Are there concerns that were not addressed here? We’re here to help.
References
- Dole, J.M. and Wilkins, H.F. (2005). Humidity and Indoor Plants. Journal of Environmental Horticulture, 23(4), 208-211.
- Fonteno, W.C., Bilderback, T.E., Carlson, W.H., and Eaker, T.A. (1993). Humidity Management for Interior Plants. Journal of the American Society for Horticultural Science, 118(1), 1-6.
- Lohr, V.I. and Pearson-Mims, C.H. (1996). Particulate Matter Accumulation on Horizontal Surfaces in Interiors: Influence of Foliage Plants. Atmospheric Environment, 30(14), 2565-2568.
- Mattson, N.S., Sinclair, T.R., and Garton, G. (1989). Effects of Container Media and Cover on Water Loss and Carbon Dioxide Exchange of Potted Poinsettia. Journal of Environmental Horticulture, 7(1), 19-22.
- Beattie, D.J., Turnbull, C.G.N., and Hough, R.L. (2000). The Use of Foliar Sprays to Increase Leaf Relative Humidity and Reduce Water Loss from Cut Roses. Journal of the American Society for Horticultural Science, 125(4), 461-466.
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