What Is LECA – And Why Should You Use It For Indoor Gardening?

by | Apr 2, 2021 | Tips | 0 comments

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LECA (usually pronounced leh-cuh) is an acronym that stands for lightweight expanded clay aggregate. While that might seem confusing at first glance, stay with us. LECA is just clay pebbles that you use instead of soil or a potting mix. But unlike these other growing media, LECA has a self-watering feature that works incredibly well for indoor plants. 

We’ve been using these little clay pebbles for a few years, and it’s easy to see why they’ve taken the houseplant world by storm. Devri recently grew bamboo with LECA, and I have used it for hydroponic beans. It’s a popular growing medium that doubles as a basic hydroponics system.

Let’s dive into the world of LECA, including its pros and cons, so you can decide if it’s the right choice for your plants.

What Is LECA For Plants?

LECA refers to small clay balls cooked in a rotary kiln at a high temperature. This low-density clay aggregate has a wide variety of benefits for plants. 

Where Can You Buy LECA Pebbles?

You can find LECA at most home and garden centers, including those at Home Depot. You can also purchase these clay pebbles from online sellers, such as Amazon.

Brands Of LECA

Benefits Of Using LECA

LECA’s properties provide a wide range of benefits for indoor and outdoor plant growers alike. If you’re still on the fence about using these small clay pellets for your garden, check out its exceptional qualities.

Consistent Water Supply

The gaps between the clay balls and the open spaces within the LECA serve as wicks or capillaries, drawing water up to the plant. This means that your plants are getting water at the right time. It also means that you don’t have to water your plants as frequently. This basic hydroponics system is doing it all for you!

Reusable

Unlike soil, which loses its nutrients over time and is discarded, you could keep using LECA forever (if you clean it between uses). While LECA is more expensive than soil, you’ll quickly recoup the initial investments when you use it for multiple harvests.

Aeration

The air pockets within the clay balls and the gaps between them allow oxygen to reach the roots. This stimulates plant growth while also avoiding bacterial and fungal infections, as well as root rot.

Stability

When a plant’s roots grow into the LECA, the clay balls act as a stabilizing structure. This keeps your plant from falling over as it grows.

Versatile

We talk a lot about plant soils and potting mixes on this blog. And some plants need one kind of soil, while other plants require another type. But LECA is incredibly versatile. It works for almost every type of plant. This means that you spend less space storing a variety of different mixes. 

Cleaner Than Soil

As someone who grows plants in an indoor space, I’m keenly aware of the amount of mess soil can make. With LECA, the only mess you need to worry about is a little dust that puffs up when you open the bag. And sure, you may still spill your LECA bag now and again, but it’s much easier to clean.

LECA Aesthetic 

LECA is strangely beautiful. It can turn a basic potted plant into an accent piece. Devri and I are always trying to walk this fine line where we want plants to live in our home – but we don’t want them to overwhelm our home.  We aim to be plant enthusiasts – not crazy plant people. So we’re regularly looking for ways to make our plants fit with our condo’s look and feel. So any time we can heighten the look of our houseplants, we’re about it.

By the way, if you’re a self-realized crazy plant person, more power to you! LECA is an excellent option for you, as well. 🙂

Cons Of LECA

Like all things, there are a few pitfalls with using LECA. We think that the pros far outweigh the cons, but here are some things to consider before you commit to the clay pebbles.

It’s Expensive

You can typically expect to pay three to four times as much on LECA than you would on traditional soil or some potting mixes. So it’s not a cheap transition. BUT – once you have the LECA, you don’t have to keep going to the garden center month after month to get more. Think of it as an investment in your gardening future.

Requires Fertilizer

Besides the high initial investment, you’ll need to buy hydroponics fertilizer or liquid fertilizer tailored to your plants. LECA’s only role is to water your plants; it does not have any nutrients.

PH Monitoring 

LECA balls are chemically inert and inorganic – with a neutral pH. Since pH affects nutrient availability for your growing plants, getting it right is critical. A pH level that’s too high or alkaline may prevent nutrients from being absorbed, resulting in a deficiency. In young plants, iron deficiency causes pale or yellow leaves, while calcium deficiency causes leaf cupping and tip burn. Calcium may also form salts on reservoir walls and machinery, which leave white deposits or scale.

In other words, when using LECA, you need to monitor your pH levels regularly and change them as needed. To maintain proper pH levels, “pH up” and “pH down” products are available. These come in both dry and liquid forms and should be used according to the bottle’s instructions. Make sure you’re using products designed for hydroponic systems.

To gauge your water’s pH levels, we recommend you purchase a digital pH meter to get an accurate result.


New Pots

We have some bad news. You know that trove of pots you’ve been hoarding? If they have drainage holes, they may not work well with LECA. For LECA to work properly, you typically need a closed-bottom pot or container. The water doesn’t drain out but is instead absorbed by the LECA. 

That said, if you’re using LECA balls as part of a hydroponic system, you’ll want to use net cups with the water flowing beneath them. Here are some net cups that work well with LECA.


How Do You Transfer Plants From Soil To LECA?

Ready to make the change from soil to LECA? Great. Follow these steps, so the process goes off without a hitch.

Remove The Plant From Soil

Instead of immediately taking the plant out of the pot, start by loosening the soil around the plant. If the soil is soft enough, you can do this either with a spade or by gently kneading it with your hands. Ripping it out of the soil can stress or even kill the plant. So this needs to be done carefully. Run your fingers through the exposed roots to remove any loose soil. There’s no need to be a perfectionist here – a few run-throughs with your hands should be fine.

Water The Roots

To get more of the soil off the plant, rinse the roots. Remember, the key here is not to damage the plant. In most cases, lukewarm tap water will work fine. Again, gently rub your hands through the roots to remove more of the soil.

Add LECA And Plants To Container

Add LECA balls to your pot. At this point, you should only fill it ⅓ of the way with the clay balls. Insert your plant, with roots sitting on top of the LECA. From here, put LECA on top of the plants’ roots.

Test Your Waters pH And Adjust As Necessary

Using a pH meter, check your water before adding it to your plants. For most houseplants, you want a pH of 5.5-6.5. If your water is below or above the desired pH levels, you’ll need to add a pH up or pH down nutrient solution.


What Does LECA Mean?

LECA is an acronym for Lightweight Expanded Clay Aggregate. Plant owners also know it as expanded clay – or “exclay.” To make LECA, clay is heated to around 2190 degrees Fahrenheit in a rotary kiln. The heat creates thousands of tiny bubbles in the clay during the process, giving the LECA its pseudo-circular shape.

  • Lightweight 
  • Expanded
  • Clay
  • Aggregate

Fun fact; LECA is also used to make lightweight concrete products!

Is LECA Better Than Soil?

Before you throw out your soil, we should point out that it’s not inherently better or worse than LECA – it’s just different. Again, LECA clay is more expensive than soil at first, but it pays off because you can use it for multiple plants or harvests. It also promotes aeration in the plant’s roots and better drainage than traditional soil. That said, you need to add liquid hydroponic nutrients to plants grown in LECA, and you’ll need to test the pH levels to make sure they’re conducive to your plant’s needs.

Can You Mix LECA With Soil?

Trying to get the best of both worlds? Yes, you can mix LECA (start with 10%) into your soil. This way, the added clay pebbles in the soil can help regulate moisture, and the soil can provide nutrients. It’s a win-win. 

Does LECA Absorb Water?

LECA balls have capillary properties, meaning they hold water, and the plant’s roots absorb them – like a wick system. However much water your plants need, they will take it from the LECA medium. Unlike other grow media, this promotes proper drainage, keeps a steady water level, and helps protect your plants from drought. 

How To Grow With LECA

Once you’ve transplanted your plants into the LECA, caring for them is simple. You’ll need to water them less than traditional growing methods, and you may see faster growth – once your plant adjusts to the new container. 

Plant care with LECA primarily consists of adding liquid fertilizer. Since LECA doesn’t have the same organic material that soil has, you need to supplement it. Be sure to use liquid nutrients intended for hydroponics


How To Prepare LECA The First Time

When you first open your bag of LECA, you may notice that it’s covered in dust. You don’t want to expose your plants to that, so give your LECA an initial soak. To do this, add the clay balls to a bucket and fill it with warm water. Rub your hands through the LECA so that it’s saturated, and then use a strainer to remove the water. Do this between three and five times.

You should probably do this outside, as the dust could make your kitchen counter messy. Once you’ve finished, you can use the LECA by adding it to your container. 

How To Grow With LECA Hydroponically

LECA is a common growing medium used for hydroponic and aquaponic systems. It’s a relatively similar process to growing in traditional nursery pots. The main difference is that the LECA and the plant sit in net pots with water either dripping onto the clay pebbles or consistently running through the bottom ⅓ of the net pot. This is an excellent way to use little water and grow plants larger and faster than traditional methods.

When growing hydroponically, you want to make sure that your plants have white roots. Brown or gray roots can be a sign that the plant is dying. 

Check out the best hydroponic systems of 2021!

How To Propagate Plants Using LECA

When propagating with LECA, you want to start by soaking and rinsing your LECA balls. Then, add the LECA to the container or pot. Unlike grown plants with preexisting root systems, you need to fill the container about halfway with LECA when growing plant cuttings.

Insert the plant cutting, and then fill the container with more LECA. There’s a good chance that the plant cutting won’t be incredibly stable at this point, but that will change as roots develop.

Test your water’s pH, and – assuming it’s between 5.5 and 6.5 – you can add it to your container. You only want to fill the container halfway full of water. 

At this point, you don’t typically need to add any liquid nutrients. Simply wait and watch – and add water when most of it in the container has either been used or evaporates. 

How Often Should You Water Plants In LECA?

When the LECA no longer touches the water beneath it, you should water your plants. While it will differ from plant to plant, you usually will need to add water every two weeks to a month. Humidity, size of container, and the amount of sunlight will all be factors as well. While you’re experimenting with LECA, continue checking the container daily until you have a good idea of when to water.

Can You Grow Any Plant In LECA?

You can grow many plants in LECA, but we specifically recommend it for most houseplants, such as ZZ plants, Monstera, and spider plants. There is less information on root vegetables and LECA, but we’re interested in trying this soon. 

Can Monstera Grow In LECA?

Monstera can grow in LECA. If you’re transplanting a grown monstera, gently remove it from the soil and rinse the roots. Add the LECA to a new container (make sure there aren’t drainage holes) until it’s about ⅓ of the way full. Insert your plant. Add more of the clay aggregate until it reaches about ⅔ of the container. Add water that’s between a pH of 5.5 and 6.5, and include liquid nutrients. 

Does LECA Prevent Pests?

Many of our least favorite, irritating pests – like fungus gnats – aren’t really after your plants. They’re more interested in the organic material that’s rotting in the soil. It’s also where they lay their eggs after mating. So having LECA helps prevent – or at least limit – the amount of gnats on your indoor plants.

On the other hand, Spider Mites lay their eggs on the leaves’ underside, so LECA won’t help you much there. 

The jury is out when it comes to aphids and thrips. Some growers say it helps, but others say it doesn’t make much of a difference. If you’ve had specific experiences with either of these pests and LECA, send an email to devri@twopeasinacondo.com. We want to hear about it!

man preparing white pot with leca pebbles

How To Clean LECA

Before we dive into the cleaning process, let’s start with the why. You need to clean LECA for a few reasons. One – you’re growing with a liquid nutrient that will develop buildups, including salt, on your LECA. This could potentially damage your plants. It looks pretty gross too. We prefer the look of a clean LECA material. 

The second reason you need to clean your clay pebbles is to remove any lingering fungus or diseases from your previous planting. 

To clean LECA, start by removing it from the container and putting it into a bowl. Rinse the clay balls in hot water. One important thing to remember about this step is to use your hands to mix the pebbles around, so they become fully saturated. Use a strainer to remove the water. Rinse and strain them again.

Now put the LECA in boiling water. Let it sit for up to 30 seconds before straining once more. Besides boiling, you can also use a solution to clean them, such as the following:

  • Isopropyl alcohol
  • Hydrogen peroxide

You typically want to let your LECA dry for a full day before using it again. 

How Long Does LECA Last?

You could technically use LECA indefinitely, assuming you’re able to remove any built-up silt or organic matter. But except for extreme circumstances, you could end up using LECA for many years.

Final Thoughts On LECA

Whether you’re new to gardening or a seasoned expert, we highly recommend you give LECA a try. It’s easy to use, has a wide range of benefits, and can save you a ton of money after a few plantings. Although testing pH levels and adding nutrients takes some extra effort, it’s offset by the time you’ll save with this self-watering system. 

Have you planted with LECA recently? We want to hear about it! Send us pictures and your story to devri@twopeasinacondo.com. We may spotlight your journey in this article!

By Patrick Chism

By Patrick Chism

Patrick likes to pretend that urban gardening is just a hobby, but he’s actually prepping for the apocalypse. He’s a practical grower, specializing in hydroponics systems and grow lights. His dream is to one day feed his family with just the food he grows in his Chicago-based condo.

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My husband and I are attempting to turn our tiny city condo into an urban gardening oasis. Join us on our journey toward sustainable living and making the most of our space.

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