You love your houseplants, but do they love your house? If the humidity levels in your home just aren’t cutting it, a pebble tray for your plants might just do the trick.
Humidity is one of the most important things to consider if you’re an indoor plant enthusiast. Some of our favorite houseplants, from ferns to Venus flytraps, prefer a more humid environment to mimic the natural rainforests from which they originated. And unfortunately, the air in our homes just isn’t humid enough to keep these kinds of plants happy.
Enter the world of pebble trays, a popular method to boost the humidity levels around your plants. Making them is easy, affordable, and completely worth it!
What is a Pebble Tray?
A pebble trays, also known as humidity trays, are exactly what they sound like: a shallow tray or dish containing some pebbles and a small amount of water. They’re used to provide indoor plants with additional humidity without drowning their roots.
When you place a plant in a pebble tray, the water in the tray slowly evaporates, raising the humidity of the air immediately surrounding the plant. The pebbles also keep the roots sitting just above the water, ensuring good air circulation.
Why Use a Pebble Tray for Your Plants?
Pebble trays are one possible solution for plants that need more humidity than they can get from the air in your house. They offer two main benefits to your plants, and two for you:
- Moisture. As the water in the pebble tray evaporates, it provides a little extra moisture to the air around your plant. This is intended to help tropical plants stay well hydrated and not dry out.
- Root Aeration. By keeping the plant sitting just above the level of the water in the tray, the pebbles help to keep its roots moist but not too wet. This is the key to healthy plant roots and avoiding root rot.
- Aesthetics. Depending on the type of tray and pebbles you use, pebble trays can be aesthetically pleasing, providing a spa-like atmosphere and coordinating well with other natural décor.
- Low Cost. You can make a pebble tray using a wide range of different materials, making them a very affordable way to provide your plants with a little extra humidity.
Pebble trays are simple and easy to make, which is why they’re such a popular solution for tropical houseplants.
Do Pebble Trays Work?
You’ll see humidity trays recommended on just about every indoor gardening blog ever written. But do they work? The short answer is: yes, but only a little. Pebble trays do generate some extra humidity, but whether or not it’s an effective amount is a matter of debate amongst the houseplant community.
The water from the tray does evaporate and raise the level of moisture in the air around the plant, but unless your plant is in an enclosure like a terrarium or greenhouse, there’s nothing keeping the extra moisture near the plant. Instead, it does what gases like to do: diffuses evenly throughout the air in the room. Compared to the total volume of air, the amount of extra moisture created is insignificant and short lived. Because of this, pebble trays are unlikely to deliver the high levels of humidity that many tropical houseplants crave.
An orchid enthusiast tested the efficacy of pebble trays and found that at 1.5” above the tray, the humidity was only 3% higher than the rest of the room. At 4” above the tray it was just 2% more humid than the surrounding air, and at 1 foot above the tray there was no measurable difference. Unfortunately, such a small percentage increase in humidity won’t help your plants out too much.
What pebble trays do well is prevent the plant’s roots from sitting directly in the water of its runoff tray. By physically elevating the planter slightly above the water level, your plant’s roots will stay nicely oxygenated. This can be helpful for plant parents who struggle with overwatering and root rot.
So, should you use a pebble tray? Ultimately, it’s up to you. If you like the aesthetic and want to better aerate your plant’s roots, a pebble tray could be ideal. It certainly won’t do any harm. But if your main goal is to significantly raise the level of humidity around your plants, this isn’t the most effective approach. There are several other techniques you can try instead:
Alternatives to Pebble Trays
There are plenty of other ways to increase the humidity around your plants. Many experienced indoor gardeners recommend trying these alternatives to pebble trays if you want to raise the humidity around your plants:
- Group Plants Together. Putting all your humidity-loving plants together can help create a micro-climate that mimics what happens in a rainforest. As your plants transpire, they naturally increase the humidity around them, so the more you have together the higher the surrounding humidity will be.
- Get a Humidifier. Humidifiers are readily available online and in stores and are a convenient way to provide your plants with the climate they crave. These generate significantly more humidity than pebble trays and are what many nurseries use to keep their houseplants healthy. Look for one that allows you to set your desired humidity level and adjusts its output accordingly.
- Add Water Features. An open-air aquarium or bubbling fountain will evaporate water into the air and create a more humid environment for nearby plants. These can be much bigger and won’t need to be refilled as often as a shallow pebble tray. Aquaponic gardening is a great way to learn more about how an aquarium and plants can work together for optimal results.
- Cover Them. A terrarium, cloche, or dome is an easy way to trap moisture and create a mini greenhouse for your plant. This works more effectively because the moisture released into the air can only diffuse throughout the smaller space rather than the entire room. You can use any clear container you have that will cover your entire plant. Either prop it up slightly to allow airflow underneath, or simply raise the container periodically to allow some air in.
What About Misting?
Another humidity-raising technique you might have read about is misting. Although misting is a popular practice, spraying your plants with a fine water mist might not be as effective as many people think. Much like pebble trays, misting is unlikely to do any harm but will only provide your plants with temporary humidity that could be absorbed or evaporate within minutes.
How to Tell if Your Plant Needs More Humidity
One of the most challenging things about growing houseplants is that the signs of underwatering, overwatering, too much light, and insufficient humidity can look annoyingly similar! These similarities make low humidity difficult to diagnose.
As part of your daily or weekly watering routine, it’s good practice to examine your plants for any changes that might indicate distress. By keeping a close eye on your plants over time, you’ll be better able to catch issues early and assess what might be troubling them.
If your plant needs more humidity than it currently gets, you might see:
- Brown patches on the leaves
- Crispy and dry leaves
- Splitting leaves
- Yellowing leaves
- New leaves appear misshapen
- Wilting
- Lack of flower buds
- Flower buds dropping off
- Flowers shriveling quickly after blooming
If you notice any of these signs appearing on your houseplant, carefully consider how much water, sunlight, and humidity your plant is currently getting. You can find recommendations for your particular variety online, and slowly adjust one variable at a time to find the optimal conditions. Patience is key – plants don’t respond well to a rapid change of any kind.
Which Plants Need High Levels of Humidity?
A lot of popular houseplants come from tropical climates and do best in high levels of humidity. When you purchase a plant, its humidity needs should be indicated as part of the care instructions, or you can look the variety up online to find out what it prefers.
Plants that enjoy high levels of humidity include:
- Aralias
- Bamboo
- Bromeliads
- Caladium
- Citrus plants
- Chenille plants
- Crotons
- Dracaenas
- English ivy
- Ferns
- Ficus
- Fiddle leaf fig
- Gardenias
- Jade
- Jasmine
- Monsteras
- Nerve plants
- Oleander
- Orchids
- Palms
- Peace lily
- Peperomias
- Pitcher plants
- Plumeria
- Rosemary
- Rubber plants
- Sensitive plants
- Schefflera
- Spider plant
- Sundews
- Tillandsia
- Venus flytraps
- Weeping fig
- Zebra plants
Which Plants Don’t Like High Humidity?
There are plenty of popular houseplants that don’t enjoy high humidity and will develop fungus, lose branches, and die if kept in too humid an environment. The most common examples of these are cacti and succulents, which are native to arid deserts where humidity is extremely low.
How to Make a Pebble Tray for Your Plants
Making a pebble tray is easy enough for any plant parent to do. You can buy a decorative tray, or simply repurpose something you have lying around.
What You’ll Need
You don’t need any tools to create a pebble tray. You just need:
- A Tray – see below for easy-to-find options
- Pebbles – good options include polished river rocks, aquarium pebbles, bonsai gravel, and glass gems
- Water – tap water is fine for many plants, but many of the more sensitive varieties do better if watered with distilled water, especially if your local tap water is hard (meaning it contains high levels of minerals)
What to Use as the Tray
You don’t have to go out and buy a special tray to make a pebble tray! The tray just needs to be about 1 inch deep, and at least as wide as your plant’s leaf span.
There are plenty of effective options that you might have lying around the house right now. You could use a:
- Planter drip tray
- Pie dish
- Cake pan
- Tart dish
- Pasta bowl
- Cookie sheet
- Saucer
- Shallow tote
- Birdbath basin
How to Assemble Your Pebble Tray
Now that you have everything you need, it’s time to put your pebble tray together:
- Fill your tray with pebbles.
- Spread the pebbles flat to create an even surface.
- Pour water into the tray. You should only fill it to about halfway so that the top layer of pebbles remains dry.
- Place your plant in the center of the tray.
- Top up water as needed. As the water in the tray evaporates, you will need to add more, particularly during hot weather.
And that’s it! Pebble trays are a quick and easy project that just about anybody can create.
Frequently Asked Questions about Pebble Trays
Answers to some of the most common questions about using pebble trays for plants:
Does every houseplant need a pebble tray?
Definitely not! Pebble trays are intended to provide additional humidity to plants that grow best in a highly humid environment. Some houseplants will be happy with the normal humidity in your house, and others such as succulents prefer very low levels of humidity so would not respond well to a pebble tray. It’s a good idea to research the particular variety of plant you have to find out what level of humidity it prefers before putting it in a pebble tray.
How big should my pebble tray be?
Bigger is better. The larger your pebble tray, the more humidity it will generate. The larger the plant, the more humidity it needs. And the larger the room your plant is in, the quicker the moisture will disperse into the surrounding air.
As a general rule of thumb, choose a tray that is at least as wide as the spread of your plant’s leaves, and at least one inch deep.
Will my pebble tray attract pests?
If you keep your pebble tray clean, you should not have any problems with pests. To make sure you don’t attract any unwanted visitors, clean the pebbles and refresh the water every two or three weeks.
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