Most orchid species grow in rainforests around the world, and rainforests are humid. So how humid should the air be in your home if you keep orchids?
How much humidity do orchids need? They thrive between 60-80% humidity, which isn’t much higher than humidity in the average home (30-60%). This relatively high humidity is necessary because orchids enjoy high humidity in the wild. It stops them from losing too much water. Misting orchids is a good way of providing humidity, as is an orchid humidity tray, a humidifier, or a humidity tent. You should also consider opening a window and/or door in your orchids’ room or turning on a fan to encourage air circulation, which in turn encourages evaporation and higher humidity.
The guide below answers all sorts of questions. Obviously it looks at why orchids need such a high level of humidity, but we’ll also address things like how do you keep an orchid humid, growing orchids in a dry climate and more.
Is Humidity Good for Orchids?
Humidity is beneficial to orchids, but not unlimited and permanent humidity. Orchids enjoy conditions that are similar to those they find in the wild, and the kind of orchids you keep as houseplants all like humid conditions. But in the wild, the humidity will vary, breezes will blow, the temperature will dip and rise, and so on. As such you can’t blindly mist your orchid every few hours and keep it damp 24/7.
How Does Humidity Affect My Orchid?
One way in which humidity affects an orchid is to reduce the rate at which it loses water. Just as heat naturally moves from somewhere hot to somewhere cool, so too does moisture naturally move from somewhere damp to somewhere dry. But if the air itself is wet, this will stop much of the water from evaporating.
This can be both a good and a bad thing. On the one hand, it can keep the potting mix for longer. This ensures that your orchid gets enough water. But at the same time, if the mix stays wet for too long, then root rot can develop. High humidity also makes crown rot more likely, because any water that gets into your orchid’s crown won’t evaporate so well.
You therefore have to be aware of the humidity and able to adjust it.
Do Orchids Like Heat AND Humidity?
Humidity and cool temperatures are a bad mix.
The problem is that humidity has the effect of making cool temperatures feel cooler, and warm temperatures feel warmer. Orchids don’t like cool weather, and when that’s mixed with humidity too, they feel even cooler. As such, you should offer a combination of the right humidity at roughly room temperature.
How Much Humidity Do Orchids Need?
Orchids do best in slightly higher than normal humidity. Somewhere between 60 and 80% humidity is optimal. This isn’t far from the average humidity in a home, which is somewhere between 30-60%. How humid your home is depends on the weather your area experiences, whether you use an air conditioner, whether lots of people live in your home, and all sorts of other factors. This means that keeping your orchids at what seems like a high humidity shouldn’t be too uncomfortable for you, and that in fact, one of the rooms in your home may already be this humid.
This may seem like a wide range (60-80%). It’s even wider when you consider that orchids will survive and grow well outside this humidity range, but perhaps not thrive and become quite as large, or have blooms that last quite as long. This is another way in which orchids are more forgiving than people give them credit for; they’ve long had a reputation for dying easily and being difficult to grow, but they really aren’t.
Measuring Humidity with an Orchid Moisture Meter
It’s essential if you plan on getting your orchids’ care right to have a hygrometer.
A hygrometer is like a thermometer, but which measures humidity rather than temperature. It measures how much moisture is in the air on a range of 0% to 100%, with 100% being the maximum amount of water that the air can hold. Hygrometers can be purchased as stand-alone tools, but you can also buy two-for-one gauges that tell you both the temperature and the humidity. These are typically digital. Which you get doesn’t matter, so long as you can measure the humidity.
Again, you may find that the humidity you keep your orchids at is already suitable. But if you have an air conditioner, or you live somewhere that’s already quite dry, you may notice that the humidity is far too low to be optimal for your plants. Or, it may be too humid. But now that you know what the actual humidity is, you can adjust as necessary.
How to Provide Humidity for Orchids
There are several ways to provide your orchid with the humidity it needs. Some of these are better than others, in that they’re more consistent or more likely to provide the precise right level of humidity. And some require more effort on your part than others, too. Which you pick depends on how much time you have, and how accurately you can gauge the humidity level in your orchid’s room.
1) Do Orchids Like Being Misted?
One way of providing an orchid with humidity is to mist it. Misting is where you take a spray bottle and spray water into the air around your orchid. The water will settle on the leaves and roots of your orchid, providing slow-release evaporative moisture to keep the humidity level high over time. Plus, some of the spray will disperse into the air immediately as it’s sprayed, instantly boosting the humidity around your orchids.
Misting isn’t the best way of providing humidity, but it will do if you have no other method available to you. The problem with misting is that if you aren’t careful, too much water can settle on your orchid’s leaves. From there, it can drip down into the orchid’s crown, which is the center-spot between the two topmost leaves. Once caught in here, the water will struggle to escape or evaporate unless you manually dab it away. And if you leave it there, it can go on to cause crown rot, a condition that kills orchids. As such, if you must mist your orchids, be careful not to cause this by accident.
How Often Should Orchids Be Misted?
If you do plan on misting your orchids to keep their humidity high, we recommend doing so once per day. You should do this in the morning, as this gives the water more chance to evaporate over the coming warm, sunny day. Even if it’s gray and overcast, more water will evaporate in the daytime than at night.
You should only mist every day if you do so correctly. Mist the air around your orchid with a spray bottle that has a very good cap, meaning one that diffuses the water well. You don’t want one that squirts out a stream of water like a water gun. The tighter the nozzle and the finer the spray, the more water is immediately diffused into the air, which is exactly what you want.
2) Orchid Humidity Tray
Humidity trays are a completely different way of providing humidity. They are, as the name suggests, small trays like the kinds you typically keep houseplants on. But if you want to turn your regular tray into a humidity tray, all you have to do is fill it with rocks and a little bit of water. The water will then gradually evaporate, releasing moisture into the air bit by bit.
This has a definite advantage over misting. That’s because the water doesn’t pool up in your orchid’s crown as it does if you mist it. But at the same time, this has a definite disadvantage, since misting provides instant humidity for orchids kept in dry conditions. If the humidity level is far too low, it will take a humidity tray a long time to get it to an acceptable level.
We recommend humidity trays if you have lots and lots of orchids. One orchid, with just one tray underneath it, won’t feel much of a difference in the humidity around it. But if you have a dozen orchids, each with its own tray, they will create their own small humid corner of the room. That’s because each of the trays will give off a small amount of moisture, which adds up to a big change. Plus, each orchid gives off its own water through respiration, and this adds up too. It’s like how rainforests are so humid because there are lots of plants there… You can achieve the same effect with trays!
How Do I Make an Orchid Humidity Tray?
Making an orchid humidity tray at home is easy. All you need is a tray, some gravel, and some water—any water.
There are a few things you can do to speed up the evaporation of air from your humidity tray, though, to make it more effective. One is to make sure that the surface level of the gravel and the surface level of the water meet. You don’t want the water to be below the surface of the gravel, nor high above it. You want the gravel to jag and just through the surface of the water, as this breaks the water’s surface tension, making it evaporate quicker.
Another thing you can do to achieve the same effect is to mix a small amount of dish soap into the water. Soap breaks surface tension too. Place a dash of soap in some water and mix it in before pouring it into the humidity tray for best effect. The soap will rise to the surface of the water, but that’s good, as there it will break the surface tension in the same way that gravel would.
You can then place the humidity tray underneath your orchid’s pot. If you do, don’t place a pot with holes in it onto the tray; if you do, your orchid may drink the water, which you don’t want. You want your orchid to dry out between waterings, and this would stop it from doing that. I tend to use a plastic inner pot with holes placed inside an outer ceramic pot, which works well for me.
You’ll have to make sure that you refill the water in your orchid’s humidity tray frequently. You want it to evaporate quickly, which is why you add in the gravel and dish soap. Depending on how well you circulate the air in your room, and the level of humidity that’s already present, it can evaporate surprisingly quickly. Check each night and refill it to the point where it was before, so that the water level meets the top of the gravel.
3) Orchid Humidifier
If you live in a very dry environment, then your best bet may be a humidifier. A humidifier is like the opposite of a dehumidifier. It releases moisture into the air to a predetermined level, and keeps it at that level consistently. The beauty of it is that you set the exact humidity level you want—say, between 50 and 60%—and the humidifier keeps it at that level for as long as it’s plugged in and has access to water.
Humidifiers work best in small, closed environments like tanks and greenhouses. If you have your orchids in your living room, for example, be prepared for the humidifier to make the entire room more humid.
Humidity And Air Movement
Maintenance of the correct humidity, and of your orchid’s health, is only possible if the humidity is combined with air movement.
Evaporation relies on the movement of air to work. In still environments, water can sit on a surface, but not be evaporated even if the temperature conditions are perfect. That’s because it’s air moving over the top of the water that picks it up (evaporates it). As such, you need a gentle and consistent level of air movement to keep your orchids in suitable conditions. There are a few ways to encourage the movement of air in a room:
- Open a window. In particular, you want to create a through draft by opening windows in several rooms. If these rooms are at opposite sides of the house, air will blow through consistently. Just be sure to close any window next to your orchids by night time.
- Open a door. Air moves within a house because of the movement of the people inside it (albeit not as much as if you open a window). Having a door open allows the air to move through the house.
- Have a fan in the room. This doesn’t have to be pointed directly at the orchids, and in fact, it’s better if it doesn’t. That’s because the fan can make the water evaporate too quickly, cooling the orchid down too much. But just having a fan in the same room can still encourage the movement of air.
- Turn on any ceiling fans in your home. Ceiling fans work like regular fans, increasing air flow.
- Check the vents in your walls. Depending on the kind of heating or cooling system your house has, you may have vents in each room. Open these and your air flow will be better.
- Open a vent in the attic, or a sky light if you have one. These are very good at encouraging air movement throughout a house. Installing one might be a step too far, understandably, but if you have one—or a sky light—open it and you will immediately notice increased air flow in your home.
With increased air flow, you should notice increased evaporation. Check your orchid’s leaves and its pot, particularly the mixture at the top of the pot, to see if more water has evaporated than usual. You may find you need to water more frequently as a result, but it’s not a bad thing for your orchid to go through short dry spells anyway.
4) Quick Hints and Tips
It may not be necessary for you to buy all sorts of kit just to keep your orchid’s air humid. There may be simple things you can do straight away that will raise the humidity level to where it needs to be.
- Test your hygrometer in different rooms. One room in your home may be much more humid than the others for whatever reason, e.g. because you have the washing machine and dryer in there. You may be able to put your orchids in there, and not have to do anything else.
- Don’t place your orchids in a room with an air conditioner. Air conditioners work by drying the air out. They evaporate water from the air, which cools the air down, but leaves it drier. You can make an immediate difference by turning it off, or putting your orchids in a room where there isn’t one.
- Don’t place your orchids near a heater. The exact same applies to heaters. These dry the air out by warming it up.
- Inside vs. outside. If the humidity outside is more suitable for your orchids, open the window that they’re next to to allow it in.
Aside from that, I recommend checking your hygrometer frequently. It will tell you what humidity the room seems to level out at, in the same way as your room temperature seems to settle at a certain point on a normal day. But it will also tell you if what you’re doing is helping or making things worse, i.e. whether your humidifier, humidity tray or misting is actually helping. You can then adjust the conditions you keep your orchid in as necesssary.
How Do You Take Care of an Orchid in a Dry Climate?
If it’s very dry where you live, the hints and tips that are relevant for you may actually be different to those that other people should follow.
Take opening the window for example. While this is a good idea for those in a normal climate, as it encourages air flow, for you it may be too drying. The same applies to opening any and all vents in your house for the sake of air movement, which would backfire as you let in dry air that your orchid won’t like.
If you live somewhere very dry, I recommend trying to create a kind of self-contained bubble for your orchids. Think like a greenhouse, but indoors! You can do this by ensuring that you don’t open any window or door to the outside near your orchids. Pick a room in your home that’s far away from your front door, and don’t open the window there. You can then mist your orchid regularly to keep it humid, and only circulate air within that room with a fan.
The ‘Humidity Tent’ for Orchids
This is a final tip which you can use to help orchids that are in dire need of a humidity boost. It’s not intended to be used as a long-term solution to low humidity, but it works in a pinch. It’s the humidity tent!
There are lots of ways to make one, but the idea behind a humidity tent is to capture and retain humidity around an orchid even if the rest of the room is dry. You basically have to set up a small tent: a fabric cover of some kind—a tea towel, a t-shirt or a sheet, for example—held above the orchid where it can trap moisture. You can hold it up with sticks buried in cups filled with sand (like MissOrchidGirl does), or some other formation that works for you. So long as the tent is above the orchid, and close enough to trap humidity, it’s not a problem. It should be open on at least one of its sides.
You then have to introduce some humidity… Otherwise what’s the point!? You can mist the orchid, or just rely on the water evaporating from its mix after its last watering. Alternatively, you could soak the covering in water which it will then release gradually.
Again, this is a method we only recommend for orchids that are dried out and sick. It’s too much effort to go to for every single one of your orchids, every day, and it would leave your house a mess! I personally use misting when the humidity gets quite low, but I live in a very rainy, reasonably humid place, so that’s not often. I would say that the drier the place that you live, the more effort you’d have to go to, so the more useful an expense like a humidifier would be. But it’s up to you, and so long as your orchid is getting enough moisture, there isn’t a problem.