Lightweight expanded clay aggregate or, Leca, is a medium in which you can grow plants and other things. As with soil, Leca can be used to grow plants in. As their name suggests, Leca is baked balls of clay.
When soaked in water the clay balls expand. Unlike soil, Leca does not contain the nutrients needed for plants to thrive.
That being said, it may seem absurd to grow or even want to grow your plants in something that does not provide for your plants. Especially when the medium most commonly used, soil, has been around forever and is tried, tested, and proven.
In this article, we will look at what exactly Leca is and why it is useful for your plants.
- 1 What is Leca?
- 2 Why is Leca Useful for Plants?
- 3 A Quick Overview about Leca
- 4 Benefits of Leca in detail
- 4.1 The risk of pests is reduced
- 4.2 Plant care is made easier
- 4.3 Week-to-week maintenance is reduced
- 4.4 It is long-lasting and reusable
- 4.5 Easier to water your plants properly
- 4.6 Easier for plant ‘check-ins’
- 4.7 The perfect amount of water and nutrients are provided
- 4.8 Less storage space required
- 4.9 Not as messy
- 4.10 Allows for ample amounts of oxygen to reach plant roots
- 4.11 Full control over the pH level and nutrient balance
- 4.12 Easy to use
- 4.13 Retains moisture but encourages drainage
- 4.14 Sterile
- 4.15 Natural and renewable
- 4.16 Fairly inexpensive
- 5 Disadvantages of Leca
- 6 How to Use Leca
- 7 Which Plants are Leca Best Used for?
- 8 Final thoughts
What is Leca?
The word Leca is an acronym. It stands for “Lightweight expanded clay aggregate”. Simply put, Leca is balls of baked clay that, when soaked in water, expands. These soaked balls are then able to water the plants grown in them. These clay balls are made by being tumbled and heated inside a rotary kiln. Leca is inorganic and is not likely to rot or break down. The balls are porous and capable of not only absorbing water but nutrients that have been added into the water. This is the main difference between Leca and other mediums used for potting.
Mediums such as peat moss, soil, or bark contain nutrients, whereas Leca balls do not. The clay balls are not able to provide nutrients to plants unless it has been added to the water used when soaking them.
Why is Leca Useful for Plants?
You may be doubting what benefit a bunch of clay balls could possibly have for your plants. Well, there are a plethora of reasons as to why Leca is beneficial!
Firstly, the biggest benefit of using Leca is that it allows plenty of airflow and oxygen through to reach the plant’s roots. This encourages the growth of your plant’s roots to be healthy. It is also known to reduce fungus and bacteria growth.
There are little to no wasted nutrients from fertilizers because Leca acts as capillaries. The clay balls soak up the water that has been enriched with nutrients and easily delivers it to your plant’s roots.
Proper watering of your plants is made easier and checking in on them is simplified. Also, the risk of your plant being affected by pests is reduced!
A Quick Overview about Leca
There are always positives and negatives to a product. Here is a quick overview of what benefits and disadvantages Leca has.
The pros of using Leca
- The risk of pests is reduced
- Plant care is made easier
- Week-to-week maintenance is reduced
- It is long-lasting and reusable
- Easier to water your plants properly
- Easier for plant ‘check-ins’
- The right amount of water and nutrients are provided
- Less storage space required
- Not as messy
- Allows for ample amounts of oxygen to reach plant roots
- Full control over the pH and nutrient balance
- Easy to use
- Retain moisture but encourage drainage
- Natural and renewable
- Fairly inexpensive
The cons of using Leca
- Transition can be pricey
- Requires fertilizer and of a special kind
- May require new equipment such as pots
- More effort to get started
- Can be heavy
- Cleaning can be messy
- Clay is strip-mined
- Excellent drainage qualities may be too dry for certain plants
Benefits of Leca in detail
The risk of pests is reduced
Pests are drawn to rotting roots and soils. Roots of plants grown in Leca are less prone to root rot. With the risk of root rot minimalized, there is no attraction for pests. Also, Leca is not a live growing medium. Unlike soil, which is organic matter filled with nutrients, the clay balls do not have any living organisms and therefore provide nothing of interest for any bugs or pests.
As for pests that thrive in environments that are dry, Leca creates a humid environment without the effort of misting.
You may think that because the Leca balls absorb the water, the environment around your plant will be ideal for dry-environment-loving pests. This is untrue. Because of the gaps around the clay balls, evaporation has plenty of opportunities to take place.
With evaporation taking place, the plant’s immediate environment stays humid which rules out the risk of attracting pests like spider mites.
Plant care is made easier
As Leca regulates moisture, there is no risk of accidentally overwatering your plants. Even with consistent watering, the Leca will absorb the supplied water and water your plants for you. As long as there is always water in the pot for the clay balls to soak up, the Leca will take care of the rest.
The only challenge you may face with your plants is providing them with the right amount of exposure to the sun. When plants are grown in soil and begin to lose their color or vibrancy it could be a combination of improper care problems.
It is possible that, when grown in soil, your plant could experience improper exposure to the sun or problems with its watering schedule
However, when grown in Leca, the risk of over or under-watering your plant is eliminated. This then makes it easier to determine what your plant needs more or less of as the only other variable is sun exposure.
Week-to-week maintenance is reduced
Plants grown in soil require regular maintenance in the form of watering. The regularity of this maintenance can vary from every two to three weeks to as often as every day or two.
Leca, on the other hand, absorbs water and then regulates the moisture. Your plant is able to access and absorb the water it requires at its own pace.
The only time it would be necessary for you to ‘water’ your plant is if the water in your plant’s pot has been completely absorbed by the Leca. There should always be a bit of water in the bottom of your plant’s pot for the clay balls to absorb when they need to.
The time it takes for the Leca to fully absorb all the water available to it could take weeks. Although, it is possible for this to vary depending on what time of year it is. Nonetheless, Leca is capable of extending the time between maintenance periods.
It is long-lasting and reusable
Unlike soil that eventually runs out of nutrients and needs to be replaced, Leca is reusable. Although the Leca itself does not have any nutritional value, it is 100% reusable!
When repotting a plant, if it was grown in soil, the soil would have to be disposed of and replaced with fresh soil. With Leca, the plant as well as the clay balls it is grown in can simply be transferred to its new pot.
This is not only true for repotting, however, but Leca can also be reused for a different plant! Provided the clay balls are cleaned properly beforehand, they can be used over and over again. It is even possible, with the right care, cleaning, and maintenance, for Leca to last forever!
Easier to water your plants properly
Leca allows the plant grown in it to drink as much water as it wants, when it wants, without the risk of issues such as root rot.
Even if you add more water to your plant’s pots and the Leca balls are still full, the plant cannot be overwatered. This is due to the plant’s roots being elevated therefore they will not be left sitting in water for extended periods of time.
With the clay balls watering your plants for you, there is no worry as to how much or how often to add water. So long as there is always water at the bottom of the pot for the Leca to soak up when needed, your plant will be happy and watered according to its preferences.
Easier for plant ‘check-ins’
Typically, the only time you are able to see the state of your plant’s roots when they are grown in soil is when you repot them. This is not the case with growing plants in Leca. Growing plants in these clay balls mean that it is possible to see the growth and progress of your plant’s roots. This is simple and fairly stress-free for your plant.
The perfect amount of water and nutrients are provided
As previously mentioned, Leca distributes moisture and the plants are able to access and absorb as much as they desire as often as they desire.
The same is true for nutrients. Because these clay balls are nutrient-free, fertilizer needs to be added to the water that the Leca balls are soaking in.
The nutrients are absorbed with the water, into the Leca and then distributed as the plant requires it. So, your plants will constantly be drawing both food and water from the Leca at a rate that suits them.
Less storage space required
Plants can be very particular about the kind of soil they are grown in. Often times it is necessary that you have more than one kind of potting soil as your plants have different needs.
Although there is the option of an all-purpose type soil, not every plant likes to be planted in them.
Leca, however, can be used for just about any type of plant! When using Leca, all you need is enough to fill your desired pots. And because it is reusable, you will not likely need to store any extra for repotting. The only reason you may need more is if you get more plants!
Not as messy
When repotting your plants or even just watering them, when they are grown in soil it is bound to make a mess. It is often the case that even when the utmost caution is being taken to avoid spillage, some soil escapes and makes a mess on your floors or countertops.
With Leca, there is no risk of spillage when topping up the water in your plant’s pot. The only messy part about the clay balls is a bit of dust which ceases to be problematic when the balls are soaked.
Allows for ample amounts of oxygen to reach plant roots
The clay balls not only have gaps between them when placed inside of a container, but they also have air pockets inside. These spaces allow for ample amounts of oxygen to get to the plant’s roots.
With adequate oxygen, healthy growth is promoted and the risk of fungal or bacterial infections is reduced, if not prevented.
Full control over the pH level and nutrient balance
Because Leca is inorganic, they do not break down. The clay balls are also chemically inert and therefore do not provide plants gown in them with any nutrients. Nutrients need to be added to the water that is absorbed by the Leca balls for them to be able to provide nutrients.
With that being the case, you have the ability to completely control and adjust the nutrient balance and the pH levels as is needed.
Easy to use
Leca is super straightforward to use. All that is required before use is for the balls to be rinsed and then soaked. After this is done, the balls can be added into a pot with your plant and water that is nutrient-enriched.
Occasional cleaning can be done by simply rinsing the balls. This is to remove any excess salts or plant matter that has been collected over time.
Retains moisture but encourages drainage
These balls soak up water and distribute the moisture as needed. Once full, the gaps between the balls in the pot allow for any excess water to drain to the bottom. From there, the balls will continue to soak up the water leftover as the plant absorbs moisture from them.
This creates an environment where your plant will always have access to the water it needs without physically soaking in water consistently.
Leca is a sterile material and therefore does not contain any diseases or pests. There is no reason to stress about them contaminating your plants.
Natural and renewable
Clay, being a natural resource and material means that Leca is a growing medium that is completely renewable.
Because Leca balls are capable of lasting a lifetime with proper care, they work out to be quite inexpensive in the long run.
Disadvantages of Leca
Transition can be pricey
Although they can last forever, Leca costs quite a bit more than regular soil. In order to transition all your plants to the clay balls medium, there will be a hefty cost initially.
Requires fertilizer and of a special kind
Leca does not provide any nutrients for your plants. Fertilizer needs to be purchased and added in order for your plants to eat. But, not just any fertilizer will do. It is necessary for liquid or hydroponics fertilizer to be used. This can also work out to be quite costly.
May require new equipment such as pots
Because the Leca will be doing the watering of your plants for you, pots with drainage holes will not work. The water needs to be contained in your plant’s pot in order for the clay balls to soak it up when they need to.
It may also be necessary to invest in a pH level tester. It is important that you keep a constant check on the pH level of the water provided to your plants. Inaccurate pH levels will affect the nutrient availability for your plants.
More effort to get started
Unlike soil that is ready to use, Leca needs some preparation before you can plant your plants in it. When using Leca for the first time, the balls need to be washed to remove the dust.
This process could be fairly time-consuming depending on the quantity being cleaned.
A process that is typically open the bag, grab the medium, and put it into a pot with your plant is drawn out. It now becomes a case of open the bag, grab the medium, wash it, let it soak a bit, and then put it in a pot with your plant.
Can be heavy
When the clay balls have soaked up all the water they can, they may end up being quite heavy. This makes them unsuitable for use in very large containers, specifically ones that need to be moved around.
Cleaning can be messy
Although overall Leca is not messy when it comes to watering or repotting, they are still messy. There can be quite a bit of red dust that comes off whilst washing the clay balls.
If the balls are not washed properly, any remaining dust can clog up your hydroponics system. Obviously, this will only affect those who use Leca for that type of growing.
Clay is strip-mined
Even though the clay itself is a natural material and it is renewable, the way in which it is collected is not ideal. Clay used to make Leca is strip-mined. This process of mining does not have a positive impact on the environment.
Excellent drainage qualities may be too dry for certain plants
Some plants may not be suited for growing in Leca as the environment created may be too dry. Because of the drainage qualities, certain plants may not find it satisfactory to draw moisture from the clay balls.
How to Use Leca
Leca is a fairly simple material to use but there are a few things that should be noted. The first step in the process is to rinse the Leca. This should be done under running water with the clay balls in a strainer. Continue rinsing until the water that runs through is clear.
The Leca balls then need to be saturated in water. Soaking the clay balls can be done over a few hours or they can be left overnight as long as they are fully saturated. Saturating opens the pores of the balls and allows them to expand.
When your clay balls are ready, prepare your plant for the transition. This should be done by removing the plant from its pot and cleaning its roots. Carefully trim away any dead or damaged roots and untangle those that remain.
Fill your desired pot, one without drainage holes, to two-thirds of the way with Leca. Shake the pot around a bit to settle the balls.
Carefully place your plant in the pot, holding it so that the top of its roots are level with the rim of the pot. Gently scatter the roots so that they lie loosely around the Leca.
Fill the pot the rest of the way to the rim with more Leca balls. Shake the pot lightly again to settle the clay balls once more. Do not press down the balls as they do not compact like soil. Pushing down the balls could damage the roots of your plant.
Next, mix some water with an adequate fertilizer. Remember to use a liquid or hydroponic fertilizer. Check the pH level of the enriched water to make sure it is adequate for your plant’s needs. This may take some practice to get it exactly right.
Pour the nutrient-enriched water over the Leca balls in the pot with your plant. Be sure to only fill the pot to just below the reach of your plant’s roots. You do not want your plant’s roots to be sitting in water. This concludes the transition!
It is necessary to ensure the Leca your plants are grown in always has access to nutrient-enriched water. It should take some time before the water is depleted but the Leca should never be allowed to dry out completely.
Without water to absorb, the Leca will not have moisture to supply to your plants and will in fact begin to draw the moisture out of your plants.
You should also rinse your clay balls fairly regularly. This will clean them of any unwanted plant matter or build-up of excess salts or nutrients. The Leca should also be washed thoroughly or sterilized before being reused for a different plant.
Which Plants are Leca Best Used for?
Most plants will do well when grown in Leca. The biggest challenge will be to ensure your plant has access to its desired amount of sunlight and the right amount of nutrients. Typically, plants that prefer or require conditions that are consistent or are sensitive to overwatering do exceptionally well in Leca.
To name a few plants that grow well in Leca are Spider Plants, Philodendrons, Delicious Monsters, Beets, Kale, Spring Onions, Bell Peppers, Devils Ivy, Spinach, Tomatoes, Mint, and Orchids.
Lightweight expanded clay aggregate may not be the growing medium for all, but it certainly does put up an extremely good fight! The benefits or pros of using Leca out-weight to negative aspects.
It may cost more initially, but you will be saving in the long run. Not only on purchasing a growing medium but by reducing the risk of unfortunately losing a plant to improper care.
Leca has been successfully used for years and may just be the way of the future. All you need to do is give it a try for yourself!
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.