-By Yang (Photos&Texts)
The Lightweight Expanded Clay Aggregate (LECA) – often referred to Clay Pebbles, Hydroton or Expanded Clay Pebbles, Clay Balls etc.
Air and moisture are important for almost every houseplant, and clay pebbles can help with it for a very affordable price.
Expanded Clay Pebbles
They’re produced by heating clay to over 2,000 degrees Fahrenheit (1200°C) using a rotary kiln, this process making the gases inside to fill the clay with little air bubbles which gives it that signature pebbles’ characteristic pores, making it perfect for holding oxygen as well as moisture around plant roots.
This happens naturally in volcanoes when erupting. So explains why things like pumice, akadama, kanuma are so light as well.
Goodsides of Expanded Clay Pebbels
Fantastic Root Aeration and Protection
Those porous pebbles absorb moisture and nutrient solution but won't hold any excessive water which makes it a light and airy growing medium that provides water, air and excellent drainage. The tumbled surfaces without the sharp edges that will not cut the delicate roots making them less vulnerable to pests and diseases.
Stable in pH and EC
The Clay Pebbles are pH neutral, non-degradable, which helps to prevent excess acidity build up and rather inhospitable to bugs. Besides, it will not interfere with any other mediums or nutrients you are feeding.
Relatively Cheap
They are in expensive since they last longer and can be reused. Just wash and reuse them as many times as you want they can last for years.
Downsides of Expanded Clay Pebbles
Quick to Dry Out
The excellent drainage can make them quick to dry out.
Time Consuming
Clay pebbles needs to be washed before use to avoid dust and smaller pebbles. This is especially important where pebbles are being used as the only growing medium or in a hydroponic system as it may damage some mechanics and cause issues like pipe blockage. Some pebbles need to be soaked to get the best possible result which is very time consuming and needs more patience.
Tap Water Problem
If using tap water, minerals will build up and block the clay’s pores, this will reduce the amount of water the clay pebbles can absorb and release. Instead, using rainwater or demineralised water will solve the problem while extend the pebbles life.
Multiple Usage of Clay Pebbles
It can be directly mixed with soil to improve soil structure or you can crush them to increase water retention in germination stage.
And some shape of pebbles also perfect for using in Flood and Drain systems, Multi-pot systems and drip-fed systems.
Use as Topping
When using alone, adding a layer of pebbles to the top as a top dressing to prevent bugs from laying eggs and stop perlite floating when watering.
Prevent Soil Leakage
Use pebbles in the bottom can help aid drainage while preventing soil leakage. Or resting pots atop of these clay pebbles, so the bottom of the pot is never in contact with water, protecting the roots inside.
