Collecting and owning houseplants has become ever-so-popular these days. Not only do they beautify our indoor spaces, but they also purify the air, create a peaceful ambiance, and simply increase our happiness.
For new (and old) plant parents, taking care of your plant’s needs can be overwhelming. From understanding why their leaves are wilting to finding the best lighting for them, there’s a lot to think about. This is where growing mediums come in handy.
In fact, it seems the latest buzzword among houseplant lovers is LECA (lightweight expandable clay aggregate). But what is this new trend, and how do we use it?
This guide will tell what is LECA and how you can use it as a medium to grow plants. As well as plants that can grow in LECA.
What Exactly is LECA?
LECA is an acronym for Lightweight Expanded Clay Aggregate. It sounds rather complicated, but it’s simple to explain.
LECA is inorganic clay pellets for plants, meaning it cannot rot or break down. These baked clay balls soak up a little water and then expand slightly. The h2O that’s soaked up in clay balls can then slowly provide water to your plants.
It was developed in 1917 in Kansas City, Missouri by baking clay at 2,190ºF (1,200ºC) in a rotary kiln. The round shape comes from the consistent rotating while baking.
The gas expands during the heating process, making little honeycomb-like holes in the clay balls, causing it to be more lightweight.
And since LECA is porous, the inorganic clay balls absorb water, causing them to expand, which helps provide the plant’s root system with water.
Unlike other growing mediums such as bark, peat moss, and soil, there are no nutrients in these clay balls to feed your plants. Therefore, any nutrients your plants need, you’ll need to add into the water.
What Does Semi-Hydroponics Mean?
Semi-hydroponics, also referred to as hydroculture or semi-hydro, is a method used to grow plants in an inorganic medium that does not decompose.
The term ‘semi’ comes from the use of non-biodegradable material (often it’s LECA) to hold the plant’s root system intact. It’s different from hydroponics, where the root system is suspended in water and nothing else.
Semi-hydroponics, also known as ‘passive hydroponics’, is done by a ‘wicking’ action to supply moisture to your plants.
The growing medium draws water upwards and provides the plant’s root system with a constant supply of water and nutrients.
What Makes LECA the Perfect Growing Medium?
Now that we have a good understanding of LECA, you may be wondering what the benefit for your plants is?
LECA makes for an excellent growing medium for house plants. For starters, it’s odorless and eco-friendly.
For many houseplant owners, overwatering is a common problem. The plant receives too much water, making the soil soggy and often leading to root rot. LECA, on the other hand, solves this common plant problem.
Benefits of Growing Plants in LECA
Take a look at some benefits of using LECA as a growing medium:
- Lessens the risk of root rot
- Extremely porous
- Cost-effective in the long run
- Environmentally friendly
- Provides the right amount of water to plants
- Takes up less storage space
- Less messy
- Can encourage drainage
- Keeps pests at bay
- It’s easier to water your plants
Drawbacks of Using LECA
It wouldn’t be fair to list the benefits of LECA without mentioning some possible drawbacks of using this medium as well.
Take a look at some possible drawbacks of using LECA:
- Can be pricey to transition
- Not suitable for cold climates
- Has poor water-retaining capacity
- You have to buy (liquid) fertilizer
- Can be costly in large quantities
- You may need to buy new pots and other tools (compared to typical growing equipment)
How to Use LECA Clay Aggregate for Plants?
If you’re wondering how plants grow in LECA, it’s quite simple. Let’s take a deeper look at how to use LECA and what you’ll need to get set up.
How Do You Grow Plants In LECA?
LECA is a means of growing your plants without soil. You’d need to create a false bottom in your plant’s pot and raise your plants’ roots from the bottom of the pot.
The space between the plant’s roots and the bottom of the inner pot is a false bottom.
You can then add your water until it sits just under the roots. Your clay balls can then start to soak up the water in the pot while keeping the plants’ roots away from the water.
Plants in LECA take in as much water as they like from the saturated clay balls. And if they are really thirsty, their roots will grow towards the water at the base of the pot and absorb directly from that.
How To Set Up A Semi-Hydroponic System
While there are several different types of set-ups for hydroponics, take a look at the most basic method. You will need:
- A plastic inner pot with drainage holes
- An outer pot or a deep saucer with no drainage holes (To hold the nutrient reservoir)
- Your growing medium (in this case, LECA)
- Hydroponic fertilizer
- A pH meter or testing kit
Step by Step: How To Convert Plants To LECA (Hydroponic Balls)
Although LECA is a fairly simple material, a few things should be noted on using these LECA clay balls for planting and while making the transition from soil to LECA.
Take a look at this step-by-step guide on how to convert your houseplant from soil to semi hydroponic clay balls.
Step 1: Soak & Rinse the Leca
- The first step in the method is to rinse the LECA clay pebbles for plants beneath flowing water, with the clay balls in a colander. Continue flushing until the water that runs through becomes clear.
- Next, soak the clay balls until they are completely submerged.
- Then, leave them in the water over a few hours or even overnight, until they become saturated in water. This will open up the pores of the balls and allow them to expand.
Step 2: Transition from Soil to LECA
Once your balls are ready, you should prepare your plant for the transition – from soil to LECA.
- Carefully remove the plant from its existing pot and clean the exposed root ball.
- Trim away any damaged or dead roots and untangle the remaining ones.
- Ensure all of the soil is removed before you plant your pot in semi hydro LECA; any soil left will remain constantly moist. This could potentially lead to root decay or mold growth.
Tip: Younger plants have less established and smaller root systems, which makes removal and adjusting to semi hydroponics much easier. It will be more difficult and much riskier for your plant to get a ‘shock’ if it’s larger or more mature. I would recommend you rather take cuttings from larger plants to propagate in LECA. Plants like Philodendron Birkins and monsteras tend to be much easier to convert, even though they are larger in size. This is due to their thicker, more robust root systems.
Step 3: Plant in LECA
Now it’s time to plant your beloved plant baby into its new clay growing medium.
- Wash the suitable amount of presoaked LECA under running water to remove any remaining dust or residue.
- Fill your pot, with drainage holes, to about two-thirds full with LECA and shake around until the balls are settled.
- Place the plant in the pot and ensure the roots are evenly spread.
- Fill the pot up to the rim with more LECA clay balls. Gently shake the pot around, and do not press the balls down. Ensure the media has made its way around the root ball.
- Then, place your pot in an outer cache or deep saucer with no drainage holes (it’s going to be your nutrient reservoir).
Note: Your plants’ roots may grow down through the LECA and the drainage holes in time and into the saucer. Ideally, you want to avoid letting your plants reach this point. To manage excessive root growth, you can remove the plant, trim the roots back, or move it to a larger pot to ensure the roots are above the waterline.
Step 4: Mix & Add a Nutrient Solution
Unlike soil or other growing mediums, LECA is an inorganic medium, meaning there are no nutrients in its contents on its own. You need to add a nutrient-rich solution to mix with your plant’s water.
So, you’ll need to dilute some hydro fertilizer with water to an adequate amount for your plants’ needs.
Tip: It’s important to note that the recommended ratios on the labels of your hydroponic fertilizers are often geared towards growing vegetables. For houseplants, you should consider using lower nutrient concentrations when you measure out your ratios.
Step 5: Check the pH Levels
Now that your hydro fertilizer has been diluted with water and is prepared for watering, it’s important to check the pH level of the solution using a pH meter or a pH testing kit.
The pH scale will indicate how acidic or how alkaline the matter is on a scale of 0 to 14, with 7 standing neutral. If the pH goes lower than 7, the solution is more alkaline. The ideal range of your houseplants’ pH level should be around 5.5 and 6.5.
Step 6: Add Hydro Fertilizer to Nutrient Reservoir
Once your plant is settled and is now in its new pot, you should then place the plastic inner pot into the deep saucer or cache. Pour the solution through the top of the inner pot until the solution reaches one to two-thirds of the height of the inner pot.
You’ll need to pour the nutrient-enriched water over your expanded clay balls in the pot with your plant. Keep in mind that you should only pour until it reaches your plant’s roots.
Step 7: Flush the Pot
Over time, you may begin to notice a white crusty salt residue appear on the surface of the LECA. When this salt crust becomes excessive, it’s time for your plant to get a flush. This can be done every one-and-a-half to two weeks.
- Remove the outer saucer and hold the pot with your plant underwater and let the water run through the pot’s drainage holes. This will allow you to ‘flush’ away from any salt build-up.
- You can also clean out the cache and add a new nutrient solution again.
Note: LECA should not be allowed to dry out completely. Without any water to absorb, the hydro clay balls are unable to supply your plants with moisture.
Where Do You Buy LECA?
This incredible lightweight growing medium can be easily found in most local nurseries such as Home Depot, Walmart, and Lowe’s. The best alternative is to purchase these organic clay pebbles online.
LECA Nutrients and Watering
As mentioned before, LECA does not provide plants with the nutrients they need to grow properly.
The clay balls only focus on keeping your plants hydrated and growing. Therefore, you’ll need to add nutrients to your plant’s water.
There are plenty of options to choose from when it comes to picking a hydroponics fertilizer, and, in general, most of them work the same.
There are also specific types of fertilizers to assist your plants, such as growth hormones.
Watering the Plant & LECA Balls
The only time you should water your plants is when the LECA is no longer in contact with the water reservoir.
You should check your plant occasionally and monitor its levels. Your plant’s watering needs would also depend on the size of the pot, the humidity in the house, and the type of plant.
The frequency at which you would need to water your houseplant will vary and is based on different factors.
For example, the average watering cycle for a 6-inch plant in soil is around two weeks. With hydroculture, the frequency of your watering cycle is typically tripled.
Hydroponics Fertilizer (Nutrients)
Hydroponics fertilizer contains specific ingredients that normal fertilizers don’t include. Which is needed when you don’t have soil to provide nutrients to the plant.
Plants in LECA
I’m sure you’re now asking: “Can my plant grow in LECA?” Not all plants thrive in LECA, there are a few characteristics to look for in your plant.
Plants That Prefer to Dry Out Before Watering
If your plant prefers to dry out before being watered again, it may be a good candidate for growing in LECA. One of the benefits of this growing medium is water regulation throughout the plant’s pot.
Keep in mind, the clay balls can only soak up around 30% of their own weight, so it’s unable to give as much water to moisture-loving plants as they’d like.
Plants That Can Grow a Root System Quickly
LECA is ideal for plants that are able to grow a root system quickly. These types of plants can spread their root system in search of any water nearby. This helps them hold onto the clay balls, soaking up the moisture.
Plants that get thirsty, like the spider plant, will grow roots that reach out to absorb as much water as possible.
However, if your plant likes dry soil, it won’t spread its roots out as much, and it’ll rather use the LECA to soak up the water.
Plants That Prefer Oxygen-Rich Soil
Some, if not all, hydroponics growing mediums provide excellent drainage in between individual clay balls, which also provides your plant’s roots with plenty of oxygen.
Some plants thrive in wet soil and have developed roots that are able to survive in such environments. These tangled, twined roots generally don’t provide a lot of oxygen to their roots.
So, if you have a plant that prefers moist, compact soil, LECA may not be such a good idea to introduce hydroponics.
However, if your plant likes dry, porous soil, it will love semi-hydroponics growing mediums such as LECA.
Hydroponic Plants Rely on Nutrients
Growing mediums in hydroponics cannot provide your plants with nutrients themselves as they are not ‘live’ growing mediums. In order to feed your plants, you would need to include hydroponics fertilizer.
You can dilute this fertilizer with water before you water your plants. Your plant can then absorb fertilizer and moisture and store it in its stems and therefore won’t need to rely on soil to provide it with nutrients.
Plants That Don’t Mind Being Handled Every-So-Often
When you’re first converting your plant from soil to hydroponics, you have to clean your roots from any soil.
It can be difficult to clean your plant and get rid of any soil on your first try, and it’s likely you’ll have to clean your plant again.
After you’ve planted your plant in LECA, you would then need to check the roots by taking your plant out of the pot.
After around a month of your plant being in LECA, you should clean the clay balls and your plant’s roots.
You should ensure your plant is able to cope with being handled every so often. Some plants, like the Calathea plants, unfortunately, don’t like being handled much, so this wouldn’t make the ideal LECA plant.
Plants That Thrive in LECA
The good news about LECA is that most houseplants thrive in this type of growing medium; some of these plant families include:
If you have a plant from one of these plant families (there are many others too), then chances are, they will be happy in LECA.
Tips to Get Started With LECA
Now that we’ve got a good idea about LECA and what to expect, take a look at some tips to get you started.
- Choose plants with less dense root systems: Once you’ve selected your plant baby to make the transition from soil to LECA, it’s helpful to start off using younger plants with less condensed root systems or use cuttings from propagated plants in water.
- Use tools: To get started, you should use tools, such as a PH testing kit, self-watering pots, scissors or shears, etc., to separate your plant from the soil.
- Pick a Hydroponics Fertilizer: Because LECA provides plants with water, not nutrients, it’s essential to periodically apply some hydroponics fertilizer when watering.
LECA Frequently Asked Questions:
If you’re still curious about this growing medium, take a look at some frequently asked questions about it below.
What Plants Grow Best In LECA?
There are many plants that will thrive in LECA. These are generally plants that prefer to dry out in between watering and that do not enjoy their roots being continuously wet.
Some more common plant species that do well in LECA are:
- ZZ Plants
- Pathos (all of them)
Do I Need To Clean My LECA?
Every once in a while, you will notice your LECA beads starting to turn white from the salt build-up (calcium) in the water you’re using. It’s good to ‘flush’ this off by gently rinsing it under a tap.
LECA vs Soil: Is LECA Better Than Soil?
LECA is quite different from soil. There are, however, many benefits of using LECA. For example, using LECA rather than soil, you’ll have less risk of pests.
How Often Do I Have To Replace The Water?
The only time you should water your plants is when the LECA is no longer in contact with the water reservoir. You should check your plant occasionally and monitor its levels. Generally, you would change the water every two to three weeks.
Is LECA More Expensive Than Potting Soil?
This will depend on what soil you’re going to be comparing LECA to. However, a benefit of LECA is that once you purchase it, you’ll no longer have to buy more – unlike soil, it doesn’t decompose.
The expense is the set-up of your semi-hydroponic systems. From buying your pH testing kit to using inner and outer pots.
Do I Need Fertilizer When Using LECA?
If you want your plants to grow and be happy, you’ll need to give them plant food as LECA does not do this.
The best fertilizers are those created for hydroponics. Flora Grow is fantastic, as well as SUPER thrive.
What Is The Best Brand Of LECA Growing Medium To Buy?
There isn’t really any superior brand of LECA. Typically, Hydroton is very good, and IKEA may be a cheaper alternative.
A Footnote on The Lightweight Expanded Clay Aggregate – LECA
LECA is an incredibly versatile growing medium for houseplants. Whether or not your favorite houseplant thinks so may depend on a few things.
Like if your plant can quickly grow a root system, if it’s happy being handled every so often, or if it likes plenty of oxygen.
Now that we’ve covered a thorough look into what is LECA, how to use it as a medium to grow plants and plants that can grow in LECA. It’s time for you to try it out and let me know what you think.
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