11 Ways To Increase Humidity For Plants, And 2 Ways That Are A Waste Of Time

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If you're anything like us, then tropical plant collecting is a fun, if not slightly addictive, hobby. But creating a tropical environment in your home that helps your houseplant's thrive is easier said than done, especially when it comes to humidity. Many of our favorite houseplants come from tropical areas like humid-heavy rainforests and need that extra moisture in the air to help keep them happy. But with central A/C and heat, our indoor spaces are more like dry deserts than lush rainforests, so many plants end up with the tell-tale signs of low humidity: yellow leaves, drooping, and crispy edges.

But there are ways we can make our homes more accommodating to our leafy friends that boost the humidity in their living spaces without damaging your house. Here are 11 of our all-time favorite ways to add more humidity around your houseplants to help them thrive. Plus, we'll also talk about two methods that are often touted as sound advice, but in the end are just a waste of time, despite your best intentions. 

If your plant budget is a little tight, the cheapest option is for boosting humidity is to just group your plants together to create a microclimate. Microclimates work by circulating the small amount of moisture that evaporates from the soil or transpires from the leaves. When plants are clustered together, they trap this moisture and raise the relative humidity in their immediate vicinity. It's essentially your plants working together to keep each other happy.

First, make sure your plants are ones that need humidity, as not all houseplants are tropical and may thrive in low-humidity homes. Once you've established your plants are the right kind, try to arrange them so that you can get as many into the space as possible, because the microclimate's effectiveness may depend on how much water vapor it can trap relative to the size of the room. Three plants together in an open floor plan may not be enough, while those same three plants may be just enough in a small bathroom. But — and this is a big one — try to keep some space between the plants to encourage airflow, reducing the chance of pests or diseases infecting the whole group. 

Having an aquarium nearby is a great way to increase humidity and gives you a fantastic reason to grow aquatic plants, too. The water that evaporates from an open air aquarium is a natural part of the tank's lifecycle that you can use to your advantage, because it helps passively increase the humidity in the air surrounding the tank. The larger the tank, the more water that will evaporate, and the more humidity there will be. 

Like grouping plants together, you'll need to put your houseplants relatively close to the tank to get the maximum humidity benefits from evaporation. But this ends up having even more benefits, because your aquarium's lighting can also give your plants the bright, indirect light they love so much. There are lots of aquarium lights out there, but we recommend using a full spectrum one, like the Hygger 18W Aquarium LED Light, so that your aquatic and terrestrial plants get the wavelengths they need for optimal photosynthesis. Plus, some terrestrial tropical plants can even live in your tank! Monsteras, philodendrons, and syngoniums are great at aquarium living — just pop a cutting into the tank and have the leaves stick out of the top. The plants will help regulate ammonia and nitrate levels in your tank, making the occasional missed cleaning less of a disaster — plus, they make for a cool-looking aquascape. 

Sometimes, it's best to just keep it simple and get the right tool for the job: a humidifier. Humidifiers work great for tropical plants, because they can raise the relatively humidity of the air in a more controlled way than other options. While a whole-house humidifier is certainly a way to raise humidity in your home, most plant parents opt for the cheaper solution and get a small room humidifier, placing it close to the plants. These room humidifiers come in clutch during the winter when central heating can make the air extremely dry, or when central air conditioning does the same in summer.

The room humidifier you should get mostly depends on your budget, but go for one that uses cool air and hits the range most tropical houseplants need, which is usually around 40% to 60%. This Coolfiqu 6L Humidifier is small enough to go nearly anywhere and seems to be well rated and budget-friendly. Next, you'll need to find the perfect place for your humidifier that's close enough to your plants to deliver water vapor, without leaves overlapping its airspace, which would essentially prevent the vapor from spreading. Remember to clean it out occasionally to prevent mold growth and don't add essential oils — your plants don't need them and they'll just clog the airflow over time. 

Adding a bowl, vase, or tray of water near your plants is a simple way to mimic the benefits of a room humidifier without the cost. As water evaporates from the vase or bowl, it releases moisture into the air, raising the relative humidity — similar to the aquarium method. It's a natural, old-school passive method for humidifying the air around houseplants and is especially helpful in the winter when the dry air from furnaces can drop your home's humidity as low as 20%. Plus, you can get creative and add flowers, food coloring, or glass stones to create some ambiance.

To do this, we recommend looking for a vessel that's wider than it is tall, so that there's more surface area for the water to evaporate from. You can place the water dish near your plants, just be careful that they don't accidentally fall in or that it's not somewhere that makes it prone to getting kicked or stepped on. Some people opt for plopping it on top of their heating grates or radiators to increase the rate of evaporation, but make sure you're using a heat-safe bowl or tray to avoid a broken glass or melted plastic mess. 

Cloches make fantastic humidity domes that create microclimates around humidity-loving plants. A cloche is a small, bell-shaped cover that sometimes has a base, or may just be open on the bottom. Once a plant is placed under a cloche, the water that transpires from its leaves has nowhere to go, so it simply gets recycled into the air, raising the humidity. It's essentially an individual greenhouse for your plant and is really helpful for species that need high humidity, like orchids. 

We will say that glass cloches can get expensive, so you may want to scout your thrift stores first before buying new, or start with plastic bottles cut in half. If you have a really large plant that you can't find an appropriate cloche for, we've had success using these CLEARWARE Large Storage Bags as makeshift cloches. In our experience, calatheas and orchids work perfectly in these. Now, you may be wondering if the plant ever runs into trouble "breathing" when living in an airtight cloche or bag, but we've found that "airing it out," so to speak, once a week was more than enough to switch out the stale air for fresh. Remember that the goal is to trap humidity, so the more you expose the plant to the dry air outside of its cloche, the more work you have to do to get a higher humidity level back. 

Pebble trays are a common, but somewhat controversial, option for boosting the humidity around houseplants. The idea works similarly to the bowl of water: As water in the tray evaporates, it increases the relative humidity in the immediate airspace. What makes them so controversial, though, is two-fold. First, the evaporation doesn't work like a missile shooting straight up to your plant's leaves; it disperses throughout the air, diluting the amount of water vapor that hits your plant. Second, and probably the biggest problem, is that many people use them as a catch-all solution, expecting epic results, only to discover that said results are minimal at best. In truth, a single pebble tray won't raise humidity from, let's say, 30% to 70%, but using it the right way could give your plants a little boost. 

To use a pebble tray correctly, you'll first need a tray or saucer that is larger than the diameter of the widest part of your pot. Many pots have a tapered shape, so you've got to account for the wide top potentially blocking or pushing the rising vapor away. Fill the tray with a layer of small pebbles or river rocks and add water, making sure the water level does not reach the bottom of the pot. The pebbles will keep the pot out of the water, preventing it from seeping into the bottom soil and potentially leading to root rot. Make sure to refill the water regularly and consider using a tray for each plant, instead of one tray to produce enough evaporation to make multiple plants happy. 

If you're growing plants in a sealed grow tent and find the humidity level dropping quickly, try hanging a damp towel or cloth inside. This method works similarly to a water tray; as the water evaporates from the towels, it releases moisture into the air of the tent. However, it's probably not a great long-term solution, since it may get moldy if there's not much airflow in the tent, so you may want to consider this as an emergency option for a quick boost. We're also not sure that this method would work in a larger space, like a greenhouse or hot house, as they tend to be a little more leaky with air than a grow tent, but you can always give it a shot and see what happens.

All this method involves is moistening a few towels or cloths so that they're damp, but not dripping wet. Hang them so that they don't touch the walls, floor, or ceiling, and make sure they're not near anything electrical. Keep an eye on the towel and consider replacing it once it either becomes dry or you start to smell a musty scent coming from the tent. 

You may think a hot, humid environment is the best for your plants, but research shows that hot air can actually lower the humidity, so you may want to just drop your thermostat down a couple of degrees instead. While it's true that warm air does hold more water vapor than cold air, that's more on a macro scale than micro. For relative humidity, which is the one you need to focus on for your plants, it turns out that cooler air is key. Plus, plants that like temps a little cool, like the cast iron plant, will absolutely flourish with a little thermostat adjusting.

The trick is to not go so cold that you or your plants are uncomfortable; many plants don't do well in temperatures below 50 degrees Fahrenheit so this is supposed to be more of a subtle adjustment than a drastic change. (Plus, you wouldn't want it that cold inside your home anyway.) Generally speaking, the more popular tropical houseplants prefer a temperature range between 65 to 75 degrees Fahrenheit during the day, and around 10 to 15 degrees Fahrenheit cooler at night. So, start with just a few degrees difference from your original room temperature, staying within the safe zone. 

Your plant cabinet or grow tent is a fantastic tool for keeping a humid microclimate around your plants, but it's only as good as its seals. Leaks or gaps between doors or around zippers allow that precious moisture to escape, lowering humidity and making it harder for your plants to thrive. So, break out the weatherstripping or the double-sided tape, because a properly-sealed enclosure helps maintain a consistent environment that keeps plants happy and healthy.

An easy way to check for leaks is to hold a small fan and move it around the inside of the cabinet, using your other hand on the outside to feel for wind. For fabric tents or cabinets, duct tape or specialized repair tape, like TIANLDD's Nylon Repair Tape, can help trap humidity inside the tent, but check carefully to ensure you get every hole, as even the smallest opening will allow vapor to escape. For solid cabinets, thin weatherstripping on cabinet door frames work wonders. We like the Frost King Sponge Rubber Foam Tape, but it can be pretty thick, so get whatever works for your cabinet. Make sure your doors are still able to open and close fully, so that the weatherstripping doesn't accidentally create new gaps you'll need to deal with. Also, consider adding a fan to your cabinet to keep airflow moving, so that mold doesn't grow in that moist environment. 

You're working hard to get that humidity level just right, we know. But don't forget the simplest trick of all: closing the door to the room with plants. A closed door creates a contained space that prevents moisture from escaping and dispersing into the rest of your home. Plus, the door acts like a barrier that reduces the amount of dry air coming in from other rooms, which is especially important during the times when your furnace or central air are running, since they tend to lower humidity levels. 

Obviously, the trick to doing this is pretty straightforward — close the door — but, there are some things to consider. First, check the weatherstripping around the door; most interior doors won't have this and even a thin layer around the frame could help lock in even more moisture — just make sure the weatherstripping isn't thick enough to prevent the door from closing all the way. Also, remember that air circulation is still important as you don't want mold growth, so consider opening a window for a few minutes here and there or use a small fan; either one of these will help prevent the humidity from getting too high.

Placing your plants in a naturally humid room, like the bathroom or kitchen, is a simple way to use what you've already got. Kitchen and bathrooms typically have higher humidity levels than the rest of your home due to the everyday activities happening there, like showering and cooking. By adding plants into these rooms, you get to utilize that extra water vapor to your advantage.

However, there is some controversy around this and the efficacy depends on how much traffic the room gets. A bathroom that is only used once a day for a quick shower, for example, may not maintain enough consistent humidity for plants to thrive, as opposed to one that's used by multiple people daily. You may want to do a little detective work ahead of time by putting a hygrometer, like this Inkbird ITH-10 Digital Thermometer and Hygrometer, in the room and checking its levels throughout the day. If you're able to maintain at least a 40% humidity level, your plants should be okay. But if it dips below 40% for extended periods, it's most likely not maintaining the crucial levels your tropical plants need. 

Misting is a common tip given to new plant parents, but it's not a method we can wholeheartedly recommend. On the surface, it sounds reasonable enough: Spraying a mist of water onto the plant's leaves should create more transpiration, and more transpiration means more water vapor. But the truth it, the rise in humidity from a quick spritz only lasts until that water evaporates, which can happen in a few minutes. As a result, even daily misting won't do enough to move the needle, and you may end up with moistened plant parts that are now looking real nice to fungal diseases that love moisture.

But let's say you've got a misting bottle and are determined to make it happen. If you're able to mist your plant every few minutes during the day and leave it alone at night, we guess that could work. But you might want to try a misting fan instead, this COZII Portable Misting Fan has a remote, so that might make life easier. While we can't vouch for its overall effectiveness, in theory the fan can circulate the moisture from a fine mist, which might be better than nothing — at least for a brief period.

You've heard that moisture evaporates from the soil, so maybe adding more water to the soil means more humidity, right? Sadly, that's wrong. Overwatering, especially to compensate for dry air, is a fast track to root rot, which is a death sentence for plants. A plant's roots need oxygen to survive and constantly saturated soil essentially drowns them. In truth, you might be able to increase the humidity levels temporarily, but the cost of dead houseplants hardly makes it worth the effort. Plus, waterlogged soil tends to grow mold, which is never a good thing to have in your home.

Instead, just opt for a humidifier or divert that watering can to a pebble tray or wide bowl near a cluster of plants. These will do way more to benefit your plants and save your roots from mold and rot. And always remember to check the soil's moisture before you water, humidity levels notwithstanding.