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Plants in LECA can be fertilized using a hydroponic-specific solution added to the water. With a list of benefits and an affordable price tag, you might be considering using LECA balls in your home.
So, how do you fertilize plants in LECA? Here I cover the main systems of growing plants with expanded clay aggregate and how each should be fertilized.
You can feed your plants with ready-to-use fertilizers or follow our simple instructions to make your own nutrient solution. Read on to discover how to fertilize your plants grown in LECA.
LECA is an acronym and stands for: Lightweight expanded clay aggregate. It is produced using clay that is treated with chemicals and baked in a rotary kiln at over 2000°F.
The end product, which you use for home gardening, is small clay balls from 4mm to 25mm in diameter.
While being baked, the clay pebbles expand and harden into light balls that weigh around 250 kg/㎥. This clay aggregate is great for plant-growing, boasting characteristics of thermal insulation, moisture retention, and a neutral pH.
This growing medium, unlike soil, does not break down or provide plants with nutrients. The clay balls absorb up to 30% of their weight in water, expanding slightly once soaked.
Perhaps your houseplant has become rootbound? This is the perfect opportunity to replant using a mixture of soil and LECA.
Read my article on how to use LECA balls for a deeper dive into repotting your plant.
Use your LECA to fill one-third of your container to create a false bottom. Hold your seedling or plant in position while filling the remainder of your pot with a mixture of soil and LECA balls. Add water until you reach a level just under the roots of the plant.
Note: A transparent container lets you easily monitor your plant’s roots while adding an interesting visual element to your indoor plant collection.
The benefits include longer periods between watering your plants, less risk of root rot, and reduced risk of pests. They also make it easier to check in on your plants.
With soil, your watering schedule may require weekly monitoring. Luckily, LECA regulates the moisture in your pot by absorbing water when it is present and storing it in a way that allows the surrounding roots to absorb at a later stage.
A plant in a pot with LECA balls is less prone to root rot than one grown in soil. Over time, soil tends to compact and reduces the oxygen available to the roots of the plant.
The large gaps between the clay balls contribute to evaporation, increasing the humidity of the plant’s immediate environment.
LECA doesn’t contain live organisms and won’t decompose or rot when left submerged in water. When soil is wet for extended periods of time it attracts bugs and other types of pests.
The negatives include stunted root development, wilting of plants if incorrectly used, and reliance on fertilizer.
Fertilizing plants grown in LECA is straightforward, and often easier than fertilizing plants in soil.
The growing medium releases no nutrients and does not decompose, reducing the factors you need to consider when adding fertilizer to your plants.
A semi-hydroponic system uses LECA (or a similar growing medium) without the use of organic soil to grow plants.
It is an easy system to convert plants to and is suitable for plants that require high amounts of nutrients, high humidity levels, or well-draining soil.
Simply add a hydroponic fertilizer to your water once you have repotted your plant. Continue to monitor and water the plant over the first two weeks, as a sudden lack of water can damage the root system.
Consider investing in a high-quality fertilizer since this will be the only source of food for your plant. Add ¼ tsp of general hydroponics fertilizer per gallon of water or follow the instructions of your specific product.
After a few weeks of monitoring the plant, you can adjust the nutrient concentration accordingly. After a week, if your plant is not thriving, increase to ½ tsp of fertilizer per gallon of water.
LECA has an expanded yet hard composition thanks to the use of rotary kilns that dry, preheat, and ‘roast’ the clay pellets.
This manufacturing process creates a uniform closed-cell pore structure that allows the expanded clay to absorb a considerable amount of moisture.
The clay used to create LECA is blended and mixed to achieve a suitable consistency before being turned into pellets.
When heated, the mixture of clay in the pellets gradually expands to as much as six times in size. This expansion gives the LECA its lightweight properties.
Expanded clay aggregate has no nutritional value. While it is non-toxic, pests do not find LECA to be hospitable.
LECA has a neutral pH, is chemically inert, sterile, incombustible, and is highly resistant to chemicals and algae.
It will not compact under constant pressure or gravitational loads. LECA balls remain unchanged after use, making them lifelong gardening partners.
The LECA insulates and maintains a more constant temperature across a variety of conditions thanks to its properties of thermal insulation.
While less important in gardening applications, LECA is also a great soundproofing material thanks to its high acoustic resistance.
While the material is generally affordable, choosing a budget LECA product can lead to more expensive problems down the road.
Thanks to its durable and long-lasting nature, you won’t regret spending more money on this lifelong growing medium the first time.
How do you know if LECA balls are inferior? Clay aggregate should be produced from 100% clay. Once soaked, the LECA balls should not float.
Rough-shaped clay pellets can have sharp edges and are less suited to hydroponics. Uniformly sized clay pebbles are important if you are aiming for an aesthetically appealing home garden.
Most plants are happiest in slightly acidic soil as it affords them access to most of the nutrients available.
With both soil and semi-hydroponic setups, the alkalinity of your growing medium can shift. Why should you monitor your pH level? If your pH level is too high or too low, plants cannot function properly.
The result is a loss in their ability to absorb nutrients and grow healthily.
The acidity or alkalinity of your growing medium is measured in pH units on a scale from 0 to 14. A pH of 7 is neutral. Most cultivated plants thrive in a slightly acidic environment with a pH level of 6.5.
Every plant has a preferred range of soil acidity which should be checked before adding water with fertilizer.
If you notice your plant’s newest leaves are yellowing, it may indicate an iron deficiency. Due to the soil being too alkaline, the plant cannot absorb the iron present in the soil or fertilizer.
Creating a semi-hydroponic setup for your houseplants is the ideal beginner gardening project. You can start by repotting your existing houseplant or move your seedlings across.
Herbs such as mint, oregano, basil, rosemary, lavender, and sage are all practical and attractive to grow hydroponically.
Making hydroponic fertilizer is easy to do and doesn’t take very long. Short on time? You can buy a hydroponic fertilizer that is ready to use.
Plants require nitrogen, phosphorus, potassium, and numerous trace elements. Below are two fertilizer solutions you can create at home.
This solution has many ingredients but is still very easy to mix. You will need to combine the following:
- 255g Potassium nitrate
- 198g calcium phosphate
- 170g magnesium sulfate
- 43g powdered ammonium sulfate
- 113g monocalcium phosphate
- ½ teaspoon Iron Sulfate.
Just add 10 grams of the solution for each gallon of water you need and test the pH level before use. Houseplants have specific preferences, but they typically fall between 6 and 7.
Note: the dry ingredients may cause skin irritation, so wear goggles and suitable protection.
This is a natural solution you can use as a base recipe. It is affordable and only requires two ingredients: seaweed and Epsom salts. If you see signs of deficiency, you can supplement with a pre-made liquid fertilizer.
All you need to do is submerge 6 ounces of seaweed in a 5-gallon bucket of water. You can wrap it in cheesecloth to prevent any sediment from being released before leaving it in the sun for 5 days.
Add 5 teaspoons of Epsom salts and monitor the pH level before using the solution. Seaweed solution will typically be alkaline and should have a reading close to 7.
The following questions are common amongst gardeners new to growing using LECA and may be of assistance to you.
The best fertilizers for houseplants grown in LECA are hydroponic-specific solutions. These formulas cater to the missing nutrients that are normally provided to the plant in soil.
Regular fertilizers are unable to provide a plant grown in LECA with all the supplements it needs.
Because there is less or no soil in a semi-hydroponic system, the plant will lack nutrients and necessary trace elements.
Caring for a plant grown in LECA is easy. Firstly, ensure your plant is receiving a suitable amount of light.
Secondly, keep the water level topped up just below the plant’s roots. Thirdly, monitor the plant’s leaves and test the pH level.
An electrical conductivity test can be done to measure the total dissolved salts in a solution. A high level of salt will hinder a plant’s ability to absorb water.
You always want to use LECA that has been soaked. The water-wicking property of this growing medium means it will draw moisture away from the plant’s roots if it is added to a container dry.
You should first rinse them (avoid letting clay go down your drain), then soak for 24 hours, before soaking in new water for an additional 6 hours.
If your plant is a high-value plant you can boil the LECA balls during your last soak to ensure they are sterile before use.
- If your semi-hydroponic container holds lots of water, add the nutrients in more than one batch.
- Don’t overfill your container to prevent spilling and wasting mixed nutrients.
- Mix the powdered nutrient solution with water on the day you intend to water for the most effective results.
- If your water level drops due to evaporation, add new water as adding more nutrient solution can cause an imbalance.
It’s so simple after all! Using LECA as a growing medium for your plants at home can save you time and, in the long run, money too.
Thanks to the great plant growing properties of the clay aggregate, you can stick to a simple monitoring and watering schedule.
Choose a ready-to-use fertilizer or follow our instructions to make your own alternative. What are you waiting for? Get growing!