Over the past 5 years, no trend in Plant parenting has skyrocketed faster than planting with Leca. Just check out the Google trend for searches starting in 2018:
The clay Ball planting trend rode the pandemic’s houseplant wave and is still soaring. It’s gotten to the point that you’ve seen folks talking about plants if you’re interested in plants (or even if you’re not). LECA is now so popular that they even sell LECA balls at IKEA!
But just because you can grow plants in clay balls doesn’t mean you should, right? So if you’re considering jumping on the LECA growing train, but you’re not sure it’s the right move, this article is for you.
We’ll break down everything you must know about this growing medium before you get started, from what LECA is to why it’s good for your plants to why you may not want to use it some instances. So let’s jump right in…
What Is LECA Anyway?
LECA is an acronym that stands for Lightweight Expanded Clay Aggregate. LECA are small puffed-clay balls made by heating small balls of clay in a rotary kiln until they expand rapidly (some people describe it as “popping” like popcorn). When the bits of clay “pop,” they create a larger puffed ball filled with thousands of tiny air bubbles. The honeycomb-like structure of these air bubbles makes the clay balls incredibly light and porous.
According to Wikipedia, LECA was first developed as part of a WWI program to build concrete ships (What??? Yeah…well, guess how that turned out). But since then, it’s become popular among plant enthusiasts as both a plant growth medium (as an alternative to potting soil) and a hydroponic substrate. Thanks to a few unique qualities we’ll dive into below.
How Does LECA Work?
LECA’s small, porous clay balls, or clay pebbles, readily absorb water, making them ideal for supporting plant roots while providing sufficient moisture. In most cases, the water level is placed below the plant’s root zone, so the clay pebbles absorb water and transport it to the roots while allowing roots to simultaneously be in contact with the air, providing them with plenty of oxygen to fuel root respiration.
Unlike soil, LECA doesn’t contain any nutrients on its own. So you’ll have to fuel your plants’ growth with a hydroponic fertilizer solution to ensure they receive all the necessary elements for their growth and development.
In summary, LECA is a versatile, lightweight, and easy-to-maintain alternative to traditional soil-based gardening. Its ability to absorb and retain water, combined with its inorganic nature, makes it an excellent choice for hydroponic plant care, allowing your plants to thrive in a nutrient-rich, well-aerated environment.
So now you know what it is…but why should you consider using it?
The Benefits of LECA for Your Plants
If you’ve only planted in soil, you might feel something “unnatural” about growing in an inorganic growth medium. But your favorite plants can thrive in a soil-less environment, and using LECA brings several unique benefits that can make it a superior alternative to soil in many cases.
Improved Root Aeration
The spaces between LECA’s clay balls help to provide an adequate oxygen supply to the root system, fueling robust plant growth. Plants’ roots need oxygen to create energy, and many soil mixes make it hard to give plants both the moisture and oxygen they require. LECA makes it easier to have both, which can help you grow healthier plants.
Enhanced Drainage
LECA absorbs water into its pores, but it allows most water to drain off. As a result, your roots don’t sit in a constantly wet environment like happens with overwatered soil, keeping them healthier and reducing the risk of life-threatening root rot.
Easy Watering & Maintenance
LECA is a favorite of many busy plant parents because it requires less daily maintenance. Generally, you can add water to your planter and let it absorb over a few days. And because of the structure of semi hydro planting setups, you can generally see the roots and the water levels instead of guessing when to water your plants.
Reduced Risk of Root Rot
Root rot due to overwatering and bacterial or fungus in the soil probably kills more houseplants than anything else. Root rot can happen in LECA setups, but the balls themselves are sterile and don’t support the growth of bacteria or fungi, like soil can. Change your water frequently, and it’s unlikely you’ll have to deal with root rot.
Eco-Friendly Lifecycle
Expanded clay planting balls are made from reusable and naturally-occurring materials. Plus, you can sterilize and reuse them for years, making them an environmentally friendly growing medium.
Natural Pest Control
Finally, the inorganic clay balls are naturally pest-resistant. Common houseplant pests, such as fungus gnats, often thrive in damp soil conditions. Since LECA provides better drainage and doesn’t contain organic matter, your plants are less likely to attract those unwanted guests.
The Disadvantages of LECA for Plant Parents
We’re not picking sides in the LECA vs. soil debate, so it’s only fair that we talk about the downsides of planting in expanded clay aggregate.
More Expensive
This one may be a bit overplayed, but LECA is definitely more expensive than soil and can get a bit costly, especially when you’re just getting started. But if you sterilize and reuse your clay balls, the actual cost goes down over time. And that’s even more true if you buy your balls in bulk. For instance, this 40L bag of LECA on Amazon is enough to fill 35 to 40 5-inch planters or 10 to 15 7-8-inch pots.
Requires Fertilizer
Unlike soil, LECA doesn’t contain any nutrients to feed your plants. So you’ll need to supplement plants with hydroponic nutrients, which can be another added cost and effort. Most soil-planted houseplants will require fertilization too, but less frequently. Check out our guide to choosing the best semi-hydroponic fertilizer for more info.
Not A Good Fit For All Plants
Lastly, while LECA is an excellent growing medium for many houseplants, it may not be suitable for all plants, particularly those with small roots or that don’t particularly love moisture. Specifically, the Peace Lily is known to be a bit of a challenge. Some also recommend against growing succulents in clay pebbles, but we’ve seen great results.
How to Use LECA for Houseplants
How To Choose the Right Clay Balls
LECA balls come in a range of shapes, sizes, and manufacturers. Selecting the appropriate clay balls for your project is essential for adequate plant growth. You’ll want to choose the right size and shape to support healthy root growth. For more help finding the best clay balls for your project, check out our article on choosing the best LECA balls.
How To Choose The Perfect LECA Pot
Before you start prepping your LECA, you’ll want to ensure you have the correct planting setup. Most semi-hydro pot setups will use one of 2 options–a wicking or reservoir setup. A reservoir setup could be as simple as a clear jar. Other reservoir setups involve a pot with holes in the bottom (or a net pot) submerged into a separate container of water. Commercial self-watering planters are a prime example of a wicked semi hydro setup.
If you’re not sure which you need, check out our article on the best semi hydro configurations for growing plants in LECA.
How To Prepare LECA for Planting
Getting your LECA ready for planting is a simple 2-step process, but you’ll need to start a day or so ahead of time. First, thoroughly rinse the clay balls under running water to remove all dust and debris. Then, you should soak the balls overnight (or longer, if you want) to allow them to shed minerals and absorb enough water for your plants. After the soaking, your LECA is ready for planting!
Learn more about preparing your LECA for use here
How To Transfer Plants to LECA
To transfer a plant from soil to LECA, follow these steps:
- Remove the plant from its current pot and gently remove excess soil from the roots. Be careful not to damage them.
- Fill your new pot with a layer of prepared LECA balls, approximately one-third of the pot’s height.
- Place your plant into the pot, spreading the roots evenly across the LECA layer.
- Fill the pot with additional LECA balls until the plant is stable and the roots are well-covered.
(NOTE: If you’re transferring a water-propagated cutting or a plant from a fully-hydroponic setup, simply skip step #1)
How To Water Plants in LECA
Watering plants in LECA is slightly different from using traditional soil. To do it correctly:
- Fill a container with water and mix in your preferred liquid hydroponic nutrients.
- Water your plants from the top, taking care to saturate the balls evenly.
- Allow excess water to drain through to a reservoir, and ensure that the water level is below the plant’s lowest roots (to minimize risk of root rot, your roots should not sit in water)
Regularly check the water level in the reservoir, and never let it evaporate completely. You will also need to rinse/flush your LECA every 1-2 weeks to avoid excess salt buildup from fertilization. Learn more about flushing LECA.
How to Propagate Plants in LECA
LECA is also an excellent medium for propagating many types of plants. We recommend you use a clear container during the propagation process to ensure you can keep a close eye on root growth.
- Cut a healthy stem from your chosen plant, ensuring that there’s at least one node present.
- Remove any leaves from the lower part of the cutting.
- Dip the cutting in rooting hormone, if desired.
- Insert the cutting into a small container filled with LECA balls, ensuring the node is covered.
- Add water to the container. You want to fill the container higher than you would for a mature plant to ensure plenty of moisture is available for your cutting. But ensure the cutting itself is above the water level.
- Water and nourish the cutting as you would with a mature plant in LECA.
The cutting should develop roots within a few weeks and grow into a new plant.
How To Fertilize Plants in LECA
Growing plants in clay pebbles requires constant fertilization because, as we’ve discussed, the growing medium contains zero nutrients for your plants. Let’s take a quick look at how to ensure your LECA-grown plants get all the elements they need to grow.
Choose the Right Fertilizer
If you want your LECA-grown plants to be healthy, you need to know what they need. They need “big food” (Nitrogen, Phosphorus, and Potassium) and “small food” (like Iron, Manganese, and Zinc). Many standard houseplant fertilizers don’t include all the nutrients you need because they assume your plants will get some of them from the soil. So hydroponic fertilizers are your secret weapon. These are great because they have both “big food” and “small food” and are easy for your plants to take up through their roots.
Head to this article for help choosing the right LECA fertillizer
Prepare and Apply the Fertilizer Solution
Once you’ve chosen the right fertilizer, prepare the solution according to the manufacturer’s instructions. Err on the side of caution to prevent over-fertilization; you can always give more later, but you can’t take it back! Add the fertilizer solution directly to the water reservoir where your LECA sits, allowing the clay pebbles to absorb the nutrient-rich water and deliver it to your plant’s roots.
Timing, Frequency, and Adjustments
Fertilize your plants every two to four weeks during the growing season (spring and summer). In fall and winter, they’re less hungry, so you can feed them less. Keep an eye on your plants after their meal– are their leaves turning yellow or brown? Are they growing slowly? If yes, they might be overfed, so reduce the concentration of fertilizer next time. But if their leaves are pale or they’re growing slow, they might be hungry.
Observe them and adjust accordingly. Each plant is unique, and the key to successful LECA gardening is to learn, adapt, and change your fertilization routine as necessary.
Frequently Asked Questions
How does LECA benefit plants?
LECA provides a number of benefits for plants. It is a porous, lightweight growing medium that promotes excellent aeration and drainage. This can help prevent common issues such as root rot and over-watering. Additionally, the balls are inorganic which means it will not decompose or cause pests, maintaining a clean environment for your plants to grow in.
What plants can I grow in LECA?
Most houseplants can be grown successfully in LECA, with very few exceptions. It can also be used to grow vegetables in a hydroponic setup or to cultivate a window herb garden. Really, the only limits for L are your imagination. If you need inspiration, check out our 13 favorite plants for growing in LECA.
How does LECA compare to traditional soil?
It differs from traditional soil in several ways. While soil contains organic matter and nutrients, expanded clay pebbles are inorganic. LECA has better aeration, drainage, and resistance to pests compared to soil. However, you have to add hydroponic nutrients to LECA, since it lacks the nutrients found in soil. You can also mix LECA with soil to get some of its benefits, while retaining a more traditional approach to fertilization.
Where can I buy LECA?
LECA is fairly easy to find these days. You should be able to find pebbles or balls at any local gardening supply store or plant nursery. You can also find it online at Amazon and specialty garden sites. Here are a couple of our favorites:
- GROW!T Clay Pebbles at Amazon.com
- Hydrotron Expanded Clay Pebbles at Amazon.com
What makes LECA pebbles so special?
LECA pebbles are unique due to their porous and lightweight structure, which promotes excellent aeration and drainage. The inorganic pebbles do not decompose or attract pests, providing a clean growing environment for your plants. Their size and shape make it easy for you to keep an eye on your plant’s roots and overall health.
How do I clean LECA balls before reusing them?
First, remove all the LECA balls from your pot. Be gentle so you don’t harm the plant if it’s still in there. Next, rinse the balls under running water. This will help get rid of any dirt or small bits of roots that may be stuck to them. After rinsing, soak them in a mixture of water and vinegar (1 part vinegar to 9 parts water) for about 10 minutes. The vinegar helps kill any remaining germs or bacteria. Rinse the LECA balls again under running water to get rid of the vinegar smell. Finally, let the balls dry completely before storing them.
Can I add LECA to potting soil?
Absolutely! You can add LECA to your potting mixes for indoor or outdoor use, similarly to how you’ll see perlite used in store-bought soil mixes. LECA balls work like tiny sponges, absorbing water and then slowly releasing it. When mixed with soil, they help keep the moisture levels just right for your plant’s roots. Plus, they create little pockets of air, which helps the roots breathe better. So, by adding LECA to your potting soil, you’re giving your plants a more comfortable home where they have just the right balance of water and oxygen.
The post LECA Explained: How To Grow Healthy Plants In Clay Balls appeared first on Plant Parent Lab.
