If you read any blog about general plant care, you’ll probably see a section on the proper soils to use with your houseplants. Potting soil, or some version of it, has obviously always been the gold standard of what to plant in, but with the evolution of newer growing techniques, like hydroponics, a new substrate called LECA has been trending and is giving traditional soil a run for its money.
What is LECA and is it good for houseplants? LECA stands for “lightweight expanded clay aggregate” and is essentially small balls of superheated clay that have expanded and become porous, allowing them to retain excess moisture while still being light and airy. Houseplants planted in LECA have better access to water and nutrients and fewer issues with pests and rot.
You may be wondering why such a substrate hasn’t fully replaced traditional potting soil as the standard medium for planting. Although there are many great benefits to using LECA with your houseplants, there are considerations that need to be made before switching all of your plants over to it.
In this article, I’ll describe what exactly LECA is, the pros and cons of using it as your planting substrate, and how to make the transition from soil to LECA successfully.
What is LECA?
Like I mentioned in the introduction, LECA is an acronym that stands for “lightweight expanded clay aggregate.” Basically, it is a sterile, inorganic soil medium made by firing small balls of clay in a superheated kiln. The excess heat causes tiny air bubbles in the clay to expand as the substrate dries out, making the piece puff up into a super porous ball.
LECA is a common growing medium in hydroponics because of its superior ability to wick up moisture using capillary action and retain it for the plant to utilize as it is needed. Because of its shape, LECA provides a lot of air pockets for a plant’s roots to grow into while still having space for oxygen exchange to occur.
Is LECA Better Than Soil for Indoor Plants?
If you do a little research on LECA, you’ll find many folks who swear that is the best thing that ever happened to their houseplants. It is a pretty universal opinion that if you take the time to learn how to use LECA properly, you will see an improvement in your plants’ size, strength, and health.
Is it better than soil, though? Perhaps. I will say it is definitely different. There are a lot of pros to using LECA, which I’ll get into a little bit more later, but in order for your plants to benefit, you need to make sure you understand how to use it properly.
Because LECA is a sterile substance, proper watering habits and the addition of liquid nutrients are required to grow plants in it. For some people, keeping track of hydroponic nutrient levels and pH are far enough outside their comfort zones that traditional potting soil is an easier substrate to use.
Ready to get started? Click here to scroll down to the shopping list of things you’ll need to transition your house plants to a LECA semi-hydroponic system.
The Pros and Cons of Using LECA for Houseplants
Pro #1: LECA Makes Watering Easier
Because LECA is such a porous material, it does a great job of soaking up moisture from watering and holding onto it for the plant to use as it is needed. Because the clay balls are round and hold their shape, they never get so compacted that water drainage becomes poor or roots struggle to survive, something that can happen in potting soil over time.
LECA balls stay consistently moist over longer periods of time, while still providing space for the roots to access oxygen. Because of this, it is easier to manage water and moisture levels, which is especially good for folks who tend to neglect their houseplants from time to time.
Typically, plants growing in LECA need to be in pots that don’t have a drainage hole to maintain a water reservoir for the LECA to absorb moisture from. Watering becomes as simple as making sure the reservoir is always about 1/3 full.
Pro #2: LECA Promotes Better Roots
With LECA, water and nutrients are constantly being absorbed through the clay balls from the water reservoir, which gives your houseplant consistent access to them at all times, without ever waterlogging the root system. And, because LECA holds its shape, the substrate your plant is in stays light and airy.
This allows healthy roots to grow properly and gives them the space for critical functions, like oxygen exchange, to occur on a regular basis. Sometimes, with old or compacted soil, the density of the substrate, especially when wet, can hinder the roots from performing these essential tasks optimally, and the plant suffers as a result.
Pro #3: LECA Can Reduce Pest Infestations
Many common houseplant pests like aphids and fungus gnats establish in damp soil full of decaying organic matter. In fact, many pests live at least one part of their lifecycle in wet soil, so with LECA, you don’t have to worry about them as much.
Because LECA is considered a sterile, inorganic substrate, most pests won’t establish in or on it, so your plant is better protected. I can’t say you won’t ever have a pest issue, but because you are avoiding the organic matter most pests prefer, you should see a substantial drop in pest issues.
Other Pros of Using LECA
Besides easier watering, better plant health, and fewer pests, there are a few other reasons that LECA is considered a great substrate for houseplants.
For one, it’s pretty easy to use. It is less messy than hauling around bags of potting soil, and because most plants do well in it, LECA can replace multiple potting soil mixes (general-purpose, cactus mix, etc.).
The other great thing about LECA is that it is reusable. If you’ve already planted something in LECA, but you repot it, or it dies (sad face), you can reuse the leftover LECA as long as you sterilize it first. Typically, this just involves boiling it in a pot of water for a couple minutes.
Con #1: LECA Can Be Expensive to Transfer Over To
Although not a dealbreaker, if you want to fully commit to LECA, transferring your houseplant collection over to the new medium can be a bit pricey. (See our shopping list here.)
First, LECA is more expensive to buy than potting soil, so upfront costs may be higher. However, remember that LECA is reusable, so once you have enough of it for your collection, you won’t need to purchase more unless you buy more plants.
Second, you need to maintain a collection of hydroponic liquid nutrients. Because LECA is sterile, you need to provide the plant with all the components it needs to grow. Nutrient concentrates can last a long time (a little goes a long way), but you’ll still have to put out an initial investment for these items.
You may also need to invest in new pots or containers to use LECA properly. Because the clay wicks up moisture using capillary action, a water reservoir is often needed to maintain consistent conditions. This means any pots with a drainage hole (a must for potting soil) need to be plugged, or the plants need to be transferred to something that can sit in a reservoir. I’ll get into this more later.
Con #2: LECA Requires Nutrients
As I mentioned, LECA is sterile, so it is up to you to provide the nutrients necessary to keep the plant alive. This means that liquid hydroponic nutrient mixtures need to be properly mixed and distributed into water reservoirs for the plants to utilize.
This can be a little overwhelming at first since most of us only fertilize our houseplants every once in a while. We are used to the soil providing the bulk of organic nutrients and minerals that the plant needs, but with LECA, that task falls entirely on us.
Generally, most houseplants do just fine on a general nutrient mixture created by following the instructions on the bottles you purchase, although they may vary depending on the brand.
If you want your plants to really thrive, some work may need to be done to fine-tune a nutrient mixture specific to the variety of houseplant. This may require you to keep multiple mixtures on hand and take a bit extra work to experiment with what works well for individual plants.
Con #3: You Need to Keep an Eye on the pH
Because you are the one providing all the nutrients for the plant, it is important to test your nutrient solution to make sure you are keeping the plant within an acceptable range.
The optimal pH level for most houseplants is between 5.5-6.5. Depending on the water you use, the brand of nutrients you prefer, and other contributing factors, the pH level of your nutrient mixture can vary. If it is too far out of range, it can result in many nutrients not being available for the plant to uptake.
It is important that you pH test your nutrient solution as you mix it up to know that what you are providing your plants is within the correct range. You may also want to periodically test individual pots to ensure the water your plants are sitting in is still within a healthy range. There’s no point in pouring perfectly well-balanced nutrient solution into a pot that has a pH issue.
If you find the water in your pot is out of balance, it is best to dump the remaining liquid, flush the plant with water, and replace the nutrient mixture.
Which Plants Grow Best in LECA?
The good news is that most houseplants actually do really well in LECA! Popular favorites like Monstera, Snake Plants, Spider Plants, Orchids, ZZ Plants, and many others seem to adapt well to LECA life.
A good rule to follow is that if the plant grows sturdy roots and prefers more consistently damp soil, the transition to LECA should be pretty straightforward. Other plants that prefer to dry out more between waterings seem to do just fine, as well, because they are never actually getting waterlogged by LECA.
Now, there are some things to consider before attempting to transition a plant over to LECA. If you have a plant that doesn’t like being disturbed much or prefers not to have its root systems messed with, you might have a more challenging time successfully cultivating it in LECA.
If you have heavy feeders (like flowering plants, begonias, etc.) or plants that tend to use more water (Pothos, bamboo, Boston ferns, or various palms), just keep in mind that you may need to water them more often to provide both moisture and nutrients.
Many people have successfully grown just about every kind of houseplant in LECA somewhere, so in most cases, it is possible. However, you should really evaluate how simple you want to keep things, whether or not you want to risk a prized member of your collection, and how much work you want to put into it before you transfer a plant over to LECA.
What You Need to Get Started:
Before I get all the way into the nitty-gritty of transferring your houseplants to a semi-hydroponic system with LECA, I want to give you a list of recommendations for your needed supplies.
If your goal is to transition to LECA, you’ll obviously need to purchase the LECA itself. I buy this LECA from Mother Earth. A 25L bag weighs about 20lbs and will be enough to transition quite a few of your houseplants over, depending on the size of the individual plants.
When it comes to the vessel you’ll use with your LECA, you have two main options. You can use a jar, vase, or another container which you’ll put your LECA directly into. Or, my preference is to use a net pot inside of a cachepot. These net pots will contain your LECA and will be placed into the cachepot holding your water reservoir. In my opinion, the net pot system is easier to maintain.
As I’ll go into extensively below, houseplants planted into LECA must have nutrients added into their water. A houseplant in LECA and water alone will not thrive long-term, so a nutrient system is crucial. The most agreed-upon favorite is this system from General Hydroponics. This system includes three different nutrients which are mixed together into your water to feed your house plant over time.
Follow the instructions on your nutrient system to dilute each concentrate and create your ideal nutrient solution. Personally, I don’t create a full-strength mixture at first. I like to create a 1/4 or 1/2 strength solution and slowly increase to full strength over time.
You can use tap water for houseplants planted into LECA, but the tap does come with some complications. PH levels are often too high, and the common chemicals mixed into the municipal water supply can cause mineral build-up on your root system. Purified water is less fussy and, though it adds to the cost, significantly takes away from the time you’ll spend fussing with your plant’s system.
As I said above, pH levels can be finicky depending on the water you use for your LECA system. You’ll need to test pH levels periodically and make the adjustments needed to the water to keep your levels between 5.5 and 6.5. This kit, also from General Hydroponics, includes a testing liquid and two solutions to raise and lower your pH.
Common Questions Regarding LECA
Before I get into the steps to transplant your houseplants from soil to LECA, I want to quickly cover some common questions that come up frequently.
Can You Mix LECA and Soil for Your Houseplants?
To experience the full benefits of what LECA can do for your houseplants, it is best to use it independently, without any other kinds of potting soil. The combination of the LECA substrate and a liquid nutrient solution can substantially positively impact the health of your plants, as it encourages healthy root growth.
Mixing organic substrates, like potting soil or other forms of dirt, can make it harder to accurately provide nutrients and keep the system clean.
On the other hand, if you want to keep your plants in potting soil but would like to keep it well-aerated and draining efficiently, you can absolutely add some LECA balls into your soil mixture. The LECA will absorb water from the soil to help keep watering conditions consistent and provide additional structure to the soil, so it doesn’t compact down.
In this instance, you would forgo using hydroponic nutrient concentrates and instead care for your plant as you normally would.
What Kind of Pots Are Needed for LECA?
If you’ve read almost any article on this blog, you have probably seen us harping on the importance of proper drainage for your houseplants. When potted in traditional soil, plants need an environment where excess liquid can drain away from the root systems.
However, when using LECA, it is crucial to retain a reservoir of water for the substrate to absorb, so a closed system is required, meaning no drainage holes are present.
As long as it meets that requirement, the container you put your LECA in can really be anything, from a coffee mug or a canning jar to large ceramic, metal, or glass containers.
When using LECA, many people like to be able to see their water reservoir easily, since it is important to manage its level consistently. Because of this, you may want to opt for a net pot (essentially a nursery pot with holes or cuts on all sides of it) that sits in a planter. This way, the LECA has access to the water reservoir in the planter, but you can easily remove the net pot to check the water level or flush out the plant, if necessary.
You can also achieve this same system using nursery pots with drainage holes or, if you’re on a budget, old plastic take-out containers with slits cut in the sides placed in ramekins. Another option is to purchase pots with drainage holes that have a plug. You won’t be able to see the reservoir level as easily, but you still have the ability to drain the pot and flush it out as needed.
There are lots of different potting options out there, so above all else, make sure you choose something that works for how you want to manage your LECA plants.
How Often Should You Add Water?
This question comes up a lot because watering a plant in LECA is a lot different than watering a plant in soil. Typically, you want to wait until the top inch or two of topsoil has dried out before watering a soil-bound houseplant again. This helps keep the moisture level more consistent and avoids instances of overwatering.
With LECA, however, the clay balls are actually already regulating the amount of water available for the plant. Water travels from the bottom of the pot through capillary action from piece to piece, so as long as there is a reservoir in the pot, the LECA is absorbing liquid and making it consistently available for the root system.
This means that rather than judging if the substrate has enough moisture in it, all you really have to keep an eye on is how much water is left at the bottom of the pot. You typically want your container 1/3 of the way full of liquid so the LECA has enough of a reservoir to draw from, as it is needed.
Can Roots Rot in LECA?
Because of how LECA works, your houseplants typically won’t have an issue with root rot. Remember, not only is LECA absorbing water so that it is readily available for the root to use without ever waterlogging them, but it is also creating space in the substrate for healthy root growth to occur.
As long as the root system avoids instances of extreme wet or dry conditions, and has the room to carry out important functions like oxygen exchange, the chances of rot are very low.
That being said, root systems can still rot in LECA if you aren’t careful. Overfilling containers, transplanting plants too deep into the substrate, or letting the pH get too far out of range can all contribute to root issues, including rot.
Should You Add Fertilizer to LECA?
Don’t forget that LECA, on its own, is a sterile substance that doesn’t have any nutrients mixed into it. Obviously, if you plant something in LECA and then only provide it water, very quickly you’ll start to see signs of nutrient deprivation, and your plant won’t last very long.
So, ultimately, yes, you do need to add nutrients to your LECA. However, mixing up a batch of traditional liquid fertilizer meant for soil probably isn’t going to cut it. While you’ll be providing many of the macronutrients that are good for the plant, you might be missing out on many of the micronutrients, minerals, and trace elements that plants typically pull from soil.
Instead, you really should pick up a hydroponic nutrient system. Typically, these are a three-part system of concentrates that you mix with distilled or RO (reverse osmosis) water. Regardless of the brand, most companies make it easy to follow their instructions to create a general nutrient mixture that works for most houseplants.
As you get more comfortable with LECA and hydroponic nutrients, you can start tweaking the general formula for specific plants. There are also lots of additives that you can incorporate into your system to boost things like calcium and magnesium, or pH buffers to keep your nutrient mixture in the optimal range.
How to Change Your Plants from Soil to LECA
If you’re intrigued by LECA and want to transition your houseplants to this new medium, there are some tips and tricks you can follow that will help make things a little easier for you. Below is a step-by-step guide for transferring your houseplants to LECA.
Step #1: Prepare Your Supplies
Before you begin, you’ll want to make sure you have all of the needed supplies on hand to make your transition to LECA go as smoothly as possible. Besides a new bag of LECA, you will want to make sure you have the correct pots and whatever nutrient system you’ve decided to use. Click here to scroll back up to our shopping list for your LECA transition.
The houseplant you’re planning on transplanting should be a relatively healthy specimen that has been watered 2-3 days prior. Transplanting to LECA will put the plant under some stress, so you want to make sure that you are setting it up for success ahead of time.
Step #2: Rinse and Soak Your LECA
LECA is packaged and shipped in bags totally dry, so before you begin a transplant, you need to make sure you have washed and soaked your new LECA to prepare it for use. When you open the bag, the individual balls will be covered in a fine clay dust that you should rinse off. This can be done using a colander in the sink, or even better, spare your pipes and rinse it off outside with a hose.
Next, fill a large container or bowl with water and dump your LECA into it. You want to allow the balls to soak in the water for about 24 hours to ensure they are properly hydrated. LECA can expand up to five times its original size, so this will also help make sure you are adding the right amount into a container.
Step #3: Mix Your Nutrient Solution
You will also want to make sure you have your hydroponic nutrient system mixed up and ready for use. Typically, these nutrients come prepackaged as concentrates, so you need to measure and add them to water, according to the directions on the bottle. Again, I personally like this system from General Hydroponics.
Many brands will have a table or chart that tells you how many milliliters (or teaspoons) of concentrate to add to a liter (or gallon) of water, so be sure to pay attention to how much solution you want to end up with. Mix concentrate bottles well before use and only add one concentrate to the water at a time, making sure to mix well in between additions. This will help avoid nutrients precipitating out of the mixture where they become unusable to the plant.
You may want to consider creating a 1/4 or 1/2 strength solution to start your plants in LECA. Then, over time, you can increase to a full-strength solution.
Step #4: Remove Your Plant from the Soil
Now it’s time to get started on the transplant. Because you want your LECA to remain clean, it is important to remove as much soil from the root ball of your houseplant as possible.
I like to take the plant out of the container and gently remove as much dirt as I can with my fingers. Take your time and be careful because you want to minimize the number of roots you damage or break off during this step. Eventually, your plant with grow new water roots that are more suited for a LECA system, but for now, you still want to keep the roots as intact as possible.
If you still have a lot of soil stuck in the root ball, you can run it under a lukewarm tap to wash as much dirt away as possible.
Step #5: Pot Your Houseplant in LECA
Grab the container you will be transplanting your houseplant into and fill the bottom about 1/3 of the way full with your new, presoaked LECA pebbles. Place your plant in the pot with the roots spread out and fill around the plant with additional LECA until the container is full and the plant is supported.
You can gently bang your container against the countertop to get the LECA pieces evenly dispersed in and around the root system for more structural support. Add more LECA, as needed.
The idea with this step is that you want your plant’s root system to be potted just above the top of the water reservoir so the roots aren’t sitting in the nutrient solution. The LECA will absorb the liquid from the reservoir and provide moisture to the plant, but initially, you want to avoid any roots being submerged to avoid rot.
Later on, it’s ok if some of the new root growth is touching the water reservoir. Again, these new roots will be acclimated to growing in water.
Step #6: Add Your Nutrient Solution
After the plant has been successfully transplanted to the new container in LECA, be sure to add enough nutrient solution to the container so that your reservoir is about 1/3 of the way up the container.
Start slow and check often until you’ve added enough solution. Because your LECA has already been presoaked, they shouldn’t absorb much of the reservoir initially, but periodically check on it in the hours and days after transplanting to ensure there is enough liquid in the pot.
Step #7: Create and Follow a Schedule for Plant Care
Now that you have plants potted in LECA, you’ll want to create a care schedule that works for you and your houseplants.
Typically, you should be fine checking your plant’s water reservoirs once to twice weekly and topping off, as needed. Some people add new nutrient solution when topping off, while others just add water. Your hydroponic nutrient system should guide you on best practices depending on which system you are using.
About every two weeks, you may want to replace your nutrient solution in the pot. Simply dump out what remains and fill it with fresh solution.
If you notice your LECA accumulating white crust, there is probably a build-up of salts or minerals, so flushing your plant with clean water can help reduce this issue. You can do this by removing the pot from the water reservoir and running it under a faucet or soaking it for about a half-hour in a container of water.
Also, be sure to schedule time to occasionally pH test your plants. You will definitely want to do this every time you mix a new batch of nutrient solution, but it can also be good to test individual reservoirs to make sure nothing funky is happening to your plants. If something is off, it is best to flush the plant and replace the reservoir with fresh nutrient solution.
Making the Leap to LECA
I hope you have a better understanding of what LECA is and how it can work for your houseplants in your home. At first, the idea of LECA and semi-hydroponics can be super intimidating, but I think you’ll find that once you understand the basics and get a little hands-on experience with it, LECA can make a huge difference in the health of your plants.
Because LECA is so different from traditional potting soil, it is important to consider how to successfully make the transition to growing your plants in it. Be sure to find containers that make it easy to monitor reservoir levels. Pick a nutrient system that makes sense to you. Put effort into creating a care schedule that works for your houseplants and stick with it.
Most people I’ve talked to started out by transitioning one or two plants over to LECA, just to see how it worked, and then, within a year, transferred a good portion, if not their entire collection to it. You can definitely get carried away with it, but it just goes to show your comfort and confidence will grow as you learn more about it! Best of luck and happy planting!