How and When to Use a Pebble Tray For Houseplants

With the soaring popularity of tropical houseplants, I have heard many stories about overwatering leading to fatal root rot, yet the plant leaves appear dry and crunchy. You are not alone if you have found yourself watering a plant to death because the leaves look dehydrated.

A pebble tray for your houseplants is a very simple and low-maintenance solution to this problem. Ready to learn more? Let’s dig in and look at how to use a pebble tray, and when the situation typically calls for it.

The Humidity Dilemma

If you’ve ever struggled with keeping tropical plants alive inside the house, you likely know firsthand the challenges of creating an indoor environment with enough humidity for these plants. I have lost many a precious leaf to the scourge of dry air.

It is particularly challenging in the winter, as forced heat can zap the moisture out of the air in a contained space. 

As any HVAC specialist would advise a customer, the ideal indoor humidity level should be between 30-60%. About 50% humidity tends to be the sweet spot, right between dry sinuses and the point where moisturizer won’t absorb.

This is important for preventing mold growth and is why mildew grows in the bathroom (the most humid room in the house) much faster than in any other room.

Cacti and Succulents

To put this in perspective, drier states like Arizona and Nevada have average outdoor humidity levels of about 38%.

You can expect plants native to these areas would grow perfectly fine inside the home with a humidity level on the lower end of the spectrum. As long as you have a sunny window, cacti, and succulents are easy to grow as houseplants. 

Tropical Houseplants

On the other hand, popular houseplants like orchids, calatheas, and philodendrons hail from warm, humid climates like South America and South Asia.

These places have much more moisture in the air, so it stands to reason that the native plants to these regions would enjoy tropical environments. Depending on the genus and species, tropical houseplants prefer a humidity level between 50%-80%. 

Some tropical plants can thrive in terrariums with the warm, moist air they need. While terrariums are beautiful and interesting items to have in the home, they aren’t practical for many houseplant lovers. If your plant collection is habitually expanding like mine, you need a way to keep your plants moist above the soil, not just below. 

Humidity Options

There are four main ways to rectify the humidity predicament:

1. Move your tropical plants to high-moisture rooms like a bathroom or kitchen.
2. Buy a humidifier.
3. Mist the plants.
4. Use a houseplant pebble tray.

Grow In Humid Rooms

You can keep many plants happy if you have a bathroom with a decent-sized window and plenty of light. But that limits you to hiding your plants away where you don’t get to enjoy them as much as if they were in your more lived-in rooms. 

Add a Humidifier

Another option is to use a humidifier. Any run-of-the-mill humidifier will work if it raises the humidity to the desired level. There are three issues with this method:

1. Mold risk: Constantly leaving a humidifier on in the house can be a recipe for mold and furniture damage. 
2. High maintenance: A humidifier must be refilled daily, which can get bothersome.
3. Cleaning: For your own health’s sake, a humidifier needs to be thoroughly cleaned regularly.

Mist Your Plants

Another method of giving your plants a dose of humidity is by misting. Misting is great for moisture-loving plants. However, misting also has a few problems:

1. It can be time-consuming and tedious.
2. It may promote mold or fungal growth on plant leaves.
3. It doesn’t create long-lasting humidity.

Do you want a less problematic solution than all of the above? Consider a houseplant pebble tray. A pebble tray is a very simple way to raise the humidity level for specific plants without affecting the humidity level in the room as a whole. 

How It Works

A pebble tray for your houseplants is precisely what it sounds like. It is a dish or tray filled with pebbles and water. This tray sits beneath the plant in question. The pebbles act as a buffer between the plant roots and the water. Most tropical plants like moist but not soggy soil. In fact, more of these plants are killed by overwatering than just about any other care factor.

So, the pebbles elevate the container, keeping the plant’s “feet” from getting soggy. Then, as the water evaporates from the tray, it adds humidity to the air directly around and above it. All you need to do is fill the tray when it gets low. This will mostly coincide with watering times anyway, although the depth of the dish and the humidity level in the home will factor in. 

It almost seems too easy! But, this is one occasion where simplicity might be the answer to keeping thriving, healthy tropical plants indoors without remembering to mist them daily or dealing with peeling paint and mildew from a constantly running humidifier. 

Let’s look at the pros and cons of using a pebble tray. As with every plant care method, it is not an exact science, and you may need to experiment with what works best in your indoor garden.

Benefits

If your plant collection is on the smaller side, using pebble trays is an affordable and easy way to increase the humidity level around your plants. It also has all the benefits of increasing humidity without increasing the threat of fungus. Not all plants that like humidity also like wet leaves, so a pebble tray is superior to misting in this way.

Pebble trays are time-saving, as they don’t need to be maintained daily. They raise the humidity only in a concentrated area, so they don’t cause harm to other objects in the home or raise the risk of mold and mildew growth. 

Drawbacks

In terms of drawbacks, the main downfall of this method is that it may not quite provide enough humidity for some plants. Another issue is air circulation. In a room with ample air circulation, the evaporating water will diffuse in the surrounding space rather than rise vertically. Pebble trays work best in rooms without fans as the circulating air will nullify the effects of the pebble tray.

Finally, if you have an extensive houseplant collection (you know if I’m talking to you), using pebble trays might be more work and more expensive than a humidifier. This method can get costly if you have a large number of plants as you’re constantly sourcing new trays to tuck under them.

Pebble trays are not effective for hanging plants. The kitchen and bathroom windows are the ideal place for hanging plants. My windows are so full that there is no need for curtains!

Which Plants Need Extra Humidity?

Here is a list of common houseplants that prefer higher humidity levels:

• Fern
• Calathea (Prayer plants)
• Philodendron
• Monstera
• Orchid
• Alocasia
• Fiddle Leaf Fig
• Carnivorous Plants
• Spider Plant
• Sansevieria
• Bromeliad
• Peperomia
• Chinese Evergreen
• Bamboo
• Dracaena
• Tillandsia (air plants)
• Spathiphyllum (peace lily)

How To Make A Pebble Tray

You will need:

• A tray or saucer
• Water
• Small pebbles or river rock gravel

After gathering your materials, assemble the pebbly tray:

Find A Receptacle

The ideal container will have a slightly larger diameter than the pot your plant is in. Your tray can be as simple or fancy as you like, but ensure it is wide and deep enough to hold water. A dinner plate wouldn’t make a great pebble tray; a pie plate, on the other hand, could be just right. 

Fill The Tray With Pebbles

Fill the container to the top edge of the tray, and smooth them out with your hand or a straight edge so that the surface is as level as possible.

Add Water

Fill your tray so that the water level is just below the level of the pebbles, but not higher. You don’t want your pebbles completely submerged, which will put your plant’s roots in the standing water.

Set Your Plant Container On The Pebbles

Place the plant container in the pebble tray. The space where your container’s drainage hole lies should not be in contact with water. If it is, the standing water will keep the plant’s roots wet, which can lead to root rot. 

Refill As Necessary

It may take a few weeks to get used to the speed of evaporation in your environment, so for the first little while, check often and notice how long it takes for the water level to drop.

You may find that you can get by until the day you water your plants, in which case, the water draining from the hole in the pot will refill the water in the tray. Just be careful not to overfill the tray such that the bottom of the pot is touching the water.

*You may find that the water evaporates at different rates depending on the time of year. Higher temperatures or more use of heating and air conditioning causes the water to evaporate faster. 

Final Thoughts

If you’ve found yourself in a quandary over dry leaves and soggy soil, there is a good chance that you have a humidity problem on your hands.  A pebble tray can be a useful and low-maintenance tool in maintaining humidity around tropical houseplants.