You’ve joined several online groups dedicated to indoor gardening, and you keep seeing people tossing an acronym around: LECA. Some say it’s even better than soil. That has you wondering, what is LECA and is it more suitable than soil for your houseplants?
LECA is short for lightweight expanded clay aggregate, a clay-based growing medium that supports hydroponic gardens. The balls of clay allow air and water to travel through. However, not all plants do well when grown in LECA, so don’t disqualify soil as an option!
I’m sure you still have plenty of questions about LECA, and I’m here to provide more information. In this article, I’ll tell you exactly how LECA works as a growing medium. I’ll also delve into the pros and cons and talk about which houseplants are best grown with LECA versus plants that don’t do well when grown using LECA.
LECA for Beginners – What Is LECA?
As I stated in the intro, LECA (sometimes stylized as Leca) is an acronym that means lightweight expanded clay aggregate. I think it’s worth noting that using LECA as a growing medium for your plants is considered semi/passive hydroponics.
If you’re used to handling handfuls of soil to keep your houseplants happy, that’s the exact opposite of what LECA is.
Instead, this growing medium consists of baked balls of clay that are about equal in size to one another.
At first, it sort of looks like you’re filling your plant’s pot with Cocoa Puffs, but LECA is very beneficial, as I’ll talk more about in the next section.
Since the LECA balls are not compressed upon one another, aeration can occur easily.
Each clay ball will absorb some water, but not several times beyond its own volume like peat moss. Instead, the LECA balls will hold onto a moderate amount of water, about 30 percent of their weight.
Speaking of water, LECA supports hydroponic gardening, which is a soilless way of growing houseplants where water sends nutrients to the plant’s roots.
LECA itself is nutrient-free, for better or for worse. However, if you add nutrients such as through fertilizer, LECA can absorb those nutrients as it does the water.
This allows your houseplant to be sustained by the nutrients for about as long as it would be when using traditional potting soil, potentially even longer.
The average pH of LECA is between 5.5 and 5.7. On the pH scale, it’s more on the acidic side, but it’s not overly acidic.
The Pros and Cons of Growing Plants in LECA
Now that you better understand LECA, I want to talk about the advantages and disadvantages of this growing medium. The information in this section and the next will help you decide whether LECA or traditional potting soil best suits your indoor plants.
Let’s start with the good stuff, shall we? These are the benefits of using LECA instead of soil.
- Checking Your Plant’s Progress Is Easy
I’ve talked about this on the blog, especially in my plant care series, but one of the biggest differences between growing a plant hydroponically versus in soil is that you can’t check on your plant’s progress in the latter.
The soil obscures the root system completely. Whether you’re transplanting a cutting or tending to a fully-grown plant, you have to assume the roots are healthy.
Over time, you get used to this, and through experience, you’ll learn the signs that your plant needs more water versus less.
Growing your indoor plants in LECA always lets you check in on your plant. If there’s an issue with the roots, rather than wait until your plant’s leaves and foliage manifest symptoms, you’ll know right away.
This can provide peace of mind to many indoor gardeners, especially beginners who aren’t sure if they’re doing everything correctly. When you see white, healthy roots, you can continue caring for your houseplant and become more confident as you do.
Should something be wrong, you can rescue your plant before it’s at risk of death, potentially saving its life.
- You Can Reuse LECA Balls
On the blog, you’ll find a big post about sterilizing soil, which is a good way to give soil new life even if it had fallen victim to a fungal or bacterial disease. Yet let’s be real here, microwaving soil or pouring boiling water on it isn’t exactly the most convenient thing in the world.
LECA balls are reusable right out of the pot or container. You might have to sterilize the clay if it was exposed to diseases, and you’ll have to clean the LECA when it’s dirty, but otherwise, it’s good to go.
- Reduced Pest Risk
If you’ve had more than one pest infestation affect your indoor garden, you can wrack your brains trying to figure out where the bugs are coming from. In part, it’s moist soil that can attract insects.
The living organisms in your soil can also lure in other living organisms such as fungus gnats and the like.
The insects then notice your plant, which is full of yummy juices they can suck up to grow stronger and reproduce. Many insects then spread disease, not only to the affected plant but possibly to others as well.
When you take soil out of the equation and use a growing medium with no living organisms such as LECA, the number of pests you see will nosedive.
- No Mess
Soil may be aerated and full of nutrients, but at the end of the day, it’s dirt. No one wants dirt under their fingernails, smeared across their skin, or on their clothes. However, that tends to be exactly what happens as you garden, because hey, it’s a messy job.
It doesn’t have to be. LECA balls stay solid when submerged in water and they don’t leave a residue when you handle them. You can significantly reduce your gardening messes, which is good considering that your garden is in your home or office.
- Lowered Risk of Root Rot
I know, it seems strange that a water-based growing medium like LECA could reduce your risk of root rot, but hear me out.
A houseplant grown in LECA balls only has so much water. The plant will drink some of that water, and the LECA will absorb the rest. When the water is gone, you know it’s time for a refill.
As you’ll recall, LECA provides excellent aeration too, so any water in the pot or container can easily travel, leaving room for oxygen.
When growing a houseplant in soil, even if the plant’s pot has fantastic drainage, when you oversaturate the soil in water, you drown out the oxygen the plant needs. This is how root rot can take hold.
A diseased houseplant is more attractive to pests, so the chances of an infestation go up. That can put your plant at an even higher risk of dying.
I have to talk about the downsides of using LECA for your houseplants as well. Here’s what you need to know.
- It’s an Investment
If you’re on a budget or you just like saving a buck, LECA gardening might not be for you. You must invest in a lot of tools and equipment that you might not already own.
For example, do you have a pH monitor? If you answered no, then you need to buy one, as the pH of water can be fluid (pun intended). You’ll have to test frequently.
You can buy a basic pH monitor for about $12, but the more advanced models are usually costlier.
If all your pots and containers have drainage holes, you’ll also have to purchase new ones. Since LECA gardening uses water, if the pot had drainage holes, all that water would be gone in a matter of minutes. The pot must be enclosed.
Then there’s the price of LECA itself. Compared to regular potting soil, you could pay four times that cost for LECA balls. Sure, they’re reusable, but the initial expense hurts.
- You Can’t Use the Same Fertilizer
I’m not done. The fertilizer you stocked up on for your indoor garden does not apply to your new semi passive hydroponic garden. Instead, you need plant-specific liquid fertilizer or hydroponic fertilizer.
LECA vs. Soil – Which Is Better for Your Houseplants?
While it’d be great if you could use LECA and soil interchangeably for your indoor plants, that’s not the case. The growing medium of choice will not come down to your own preferences, but rather what your plant needs.
If your plant has these traits, then it’s suitable for growing in LECA. If it doesn’t, then stick to traditional potting soil.
Your Plant Gets More Nutrients from Fertilizer Than Its Growing Medium
I mentioned this earlier, but I want to state it again now. LECA on its own does not contain nutrients.
The clay balls can absorb some nutrients from the water when you fertilize your plant, but on their own, they’re nutritionally void.
I’ll provide steps in the next section on how to fertilize a houseplant grown in LECA, but you already know it’s with hydroponics fertilizer. The fertilizer goes in the water, your plant absorbs it, and then the plant holds onto the nutrients in its leaves or stems.
Not all houseplant species can do this or do it particularly well. For the ones that can’t, they need nutrients in their growing medium or they’ll die. You need to grow these indoor plants in soil instead of LECA.
Your Plant Likes Oxygen-Rich Conditions
The space between LECA balls creates lots of room for oxygen, as I talked about earlier. This is great for plants that require oxygen-rich growing conditions, as they’re never starved of oxygen.
Not all plants need an oxygen-rich growing medium, though. These plants often prefer compacted yet moist soil. For them, all the airiness of LECA balls could disrupt their oxygen balance.
Plants with a surplus of oxygen tend to grow less since their care requirements are already more than being met in the conditions they’re in.
Your Plant Grows Best in Acidic Conditions
To reiterate, the pH of LECA is 5.5 to 5.7. That puts it squarely in acidic territory. For many houseplants, acidic soil or clay is wonderful, but for just as many, their growing medium should be more basic or closer to neutral.
Your Plant Doesn’t Mind Being Touched
Plants can be fragile things, so it makes sense that some don’t appreciate being handled more than necessary. These houseplants are the worst candidates for LECA.
You’ll have to regularly refill the water the plant is growing in. You have to keep the LECA balls clean too.
You also have to remove all soil from the roots of your plant when transitioning it to LECA, which requires lots of touching.
Now that I’ve pointed out the 3 main characteristics that can make plants bad candidates for LECA, let me get right into a list of plants that will likely do the best when grown in LECA
Which plants are good candidates for LECA? Here are some species to start with:
- Snake plant
- Spider plant
- ZZ plant
Do you still have a few more burning questions about LECA? I’ve got answers!
How Do Plant Roots Attach to LECA Balls?
One of the things you’re worried about is that your plant’s roots won’t be able to latch onto the LECA balls.
Plant roots are fascinating things. They can attach to many surfaces, round ones included. The best plants for LECA will produce root systems fast, which increases the chance of successful attachment. The spider plant is one such example.
How Do You Fertilize a Plant Grown in LECA?
I said I would come back to this, so it’s time to talk about it. How do you use hydroponic fertilizer on a plant grown in LECA?
Like most fertilizers, it helps to dilute the hydroponics fertilizer in water before feeding it to your houseplants. You’ll likely need several gallons of water for several teaspoons of fertilizer, but defer to the instructions on your packaging.
Stir the ingredients until the fertilizer has completely dissolved. Then pour the water in when your hydroponics garden needs it. Your plants will soon be infused with nutrients.
Can You Mix LECA with Soil?
I’ve talked about LECA versus soil as an either-or scenario. Can you just combine the two?
In many instances, yes! LECA in soil provides aeration, water retention, and drainage. Do keep in mind though that LECA is acidic, so if your plant doesn’t grow well in acidic conditions, use a more basic soil amendment instead.