Clay Pebbles vs Perlite: Which is Better for plants?   

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The healthiest soil can still be prone to dirt carrying harmful fungi and bacteria. Soilless growing mediums grow plants in organic and inorganic ingredients. Clay pebbles and perlite commonly replace soil as a growing medium in hydroponic or soilless systems.

Clay pebbles and perlite grow healthier plants without the risk of soil-borne diseases. They are also less likely to be disturbed by pests. Which is best? They both have pros and cons, so it depends on each different situation. All the facts are below to help you choose which is best in your prevailing conditions at that time.

Clay Pebbles vs Perlite

It can be difficult to decide on a growing medium for your indoor garden, especially for beginners. You have several options available, the most popular of which are clay pebbles vs perlite.

Clay pebbles and perlite each have their advantages and disadvantages. The benefits of each growing medium differ depending on your circumstances. So you must take into consideration:

Your available space or square footage.

Amount of time you have for your garden.

Available funds for your garden.

It is always important to remember that the growing medium you choose should have good draining and retention properties.

• Type of Growing Media

Clay pebbles can be used alone or as a standalone growing media. It can also be used as a soil or coco amendment.

Perlite is mostly used as a soil amendment for soil or cocoa. It is not a standalone growing media.

• Water Retention

Clay pebbles and perlite have low water retention.

• Aeration Properties

Clay pebbles and perlite are great growing media with good aeration properties.

CEC, WHC, and AFP

Cation Exchange Capacity (CEC) measures the total negative charges within the growing medium that absorbs nutrients. It is the quality of the growing medium to supply nutrients to the plants.

Water holding capacity (WHC) measures how much water is retained by a growing medium.

Air Filled Porosity (AFP) is the percentage of a growing medium’s volume that is air after it has been saturated with water.

Clay pebbles have low CEC and WHC and high AFP. Thus, they are able to easily provide oxygen and are not prone to overwatering.

Perlite has very low CEC and high AFP. Thus, it is easy for this growing medium to control nutrients to the plants.

• Sanitation and Reuse

Clay pebbles and perlite can be cleaned and reused. They can be sanitized by adding 10% bleach to the water.

• Weight

Clay pebbles are heavy, making them ideal for deep water culture (DWC) systems wherein the plant roots have to always be exposed to water.

Since clay pebbles are heavy, they are stable and can provide support to your plants.

Perlite is lightweight, easily absorbs water, and floats in water. It is, however, prone to overwatering. Since it is lightweight, perlite cannot provide plant support.

• Costs

Clay pebbles and perlite can be expensive substrates. But, they are often sold pre-washed with pH levels already adjusted.

Perlite, though, is cheaper per square foot than clay pebbles. Thus it is a better choice if you are building a large hydroponic system.

So, which is better for your plants: clay pebbles vs perlite? Clay pebbles and perlite are good options for your hydroponic garden. 

The better choice, however, depends on the type of hydroponic system you want to build.

After going through the pros and cons of each growing medium and still, you are not able to make a choice, you can create separate systems for each growing medium and observe which provides your plants with a better growing condition.

The choice between clay pebbles vs perlite growing media should be based on which growing medium is suitable for your plants, including:

Which growing medium can provide structural support to your plants?

Which growing media can be a better reservoir for the plants’ nutrients?

Which growing medium can offer better water flow?

Which growing medium can provide you with a healthy environment for your plants?

In short, decide first on the plants you want to grow and then choose which growing medium between clay pebbles vs perlite to use.

Clay pebbles and perlite can also be used to amend the soil in your outdoor garden. They work the best in amending heavy or clay soils that do not have good aeration and drainage.

What are Clay Pebbles?

Clay pebbles, also known as hydroton or expanded clay pebbles, are a growing medium ideal for a wide range of plants. They are organic substances making them popular substrates to many growers.

While clay pebbles are not a growing medium that offers their own nutrients to your plants, they are a medium that allows water and nutrients to be easily added to ensure the healthy growth of your plants.

Clay pebbles are commonly used as a base layer of other growing mediums because of their excellent drainage qualities.

Clay pebbles are created by firing pieces of clay in a kiln (a type of oven or thermally insulated chamber ), allowing them to expand.

Pros

Clay pebbles have superb aeration and drainage qualities because they are lightweight and porous. This is important to prevent the plant’s root system from rotting.

They contain 100% minerals making them durable and stable.

A layer of clay pebbles is placed at the bottom of a garden box, pot, or container increases air circulation and provides protection to the roots.

Clay pebbles are sterile because they are made under very high heat.

They keep the air around the plants moist.

Clay pebbles enhance the growth of potted plants.

Clay pebbles regulate soil moisture. Clay pebbles retain moisture and release water to the plants’ roots when the soil becomes dry.

They can be reused, which means they are eco-friendly.

Clay pebbles provide proper support for your plants.

Clay pebbles are ornamental for indoor and outdoor plants. A surface layer of clay pebbles can highlight the color of your plants.

Cons

Clay pebbles are only ideal for small-scale growing. They can be expensive for large-scale commercial growth.

They dry quicker than soil.

The tons of benefits your plants can get from pebble clays allow them to be healthy and have optimal growth. For these reasons, pebble clays are becoming one of the most popular soilless growing mediums.

What is Perlite?

Perlite is a lightweight and white material. It feels and looks like tiny bits of polystyrene (a synthetic polymer), but it is formed from expanded volcanic glass.

Volcanic glass is heated to 10000C (Fusion Metamorphosis) until it pops and becomes bigger.

Similar to other volcanic rocks, perlite has a dense and heavy natural form. Perlite is typically made of:

70-75% silicon dioxide

Sodium oxide

Aluminum oxide

Iron oxide

Potassium oxide

Calcium oxide

Magnesium oxide

3-5% Water

Pros

Perlite is highly porous so that it can absorb water.

It retains some water and allows the rest to drain away.

Perlite contains pockets of space inside for good air circulation.

Perlite works well in aerating roots.

Perlite is a hard mineral, so it retains its shape and keeps air pockets around the plant’s root, which is suitable for its root systems.

Cheap, lightweight, sterile, long-lasting, and easy to handle.

It is neither acidic nor alkaline. It has a neutral pH level.

Perlite is useful in plant propagation, including sowing seeds and taking cuttings.

It is made from naturally occurring compounds in the soil, so it does not contain toxic chemicals

Perlite improves the drainage capabilities of soil because it has excellent draining and filtering qualities. The pores of perlite allow excess water to drain off.

Perlite retains its shape and remains stable even when mixed with soil. It is one of the best soil amendments.

Perlite comes with neutral pH making it a great soil amendment.

Perlite allows good air circulation around the plant’s roots allowing it to grow faster and increase its yield.

Perlite aids in water retention and improves drainage in the soil.

It is water-resistant.

Perlite does not contain nutrients or chemicals.

It can be reused.

Easily available and cheap.

It works great for gardening and hydroponics.

Cons

Perlite does not retain water, so it should be mixed with other growing mediums such as peat moss.

Perlite is non-renewable because it is a naturally occurring mined mineral.

Perlite does not contain nutrients.

Perlite emits dust, so you need to protect yourself when working with it.

Perlite tends to float in excess water.

Final Thoughts

There you have it – all the facts we can find to help you when choosing the suitable growing medium for your soilless garden. Yet, that decision still can be tedious.

Growing media serves as the anchors of your plants, providing them with nutrients, water, and oxygen to their roots.

The choice of growing media depends on the design, location, scale, and the crops you will grow.

In some instances, it also depends on the availability and costs and the experience and expertise of the grower.

It is unrealistic and difficult to answer which is better, clay pebbles or perlite, because many factors come into play, including your objectives and goals as a grower. 

As mentioned above, if you are unsure of which growing medium to use for particular plants, you can experiment with both clay pebbles and perlite to see how differently they can make your plants grow.

Your experience as a grower will tell you which is better between clay pebbles vs perlite.

Jenny Marie
Tribal Writer

Edited By
Patricia Godwin

Patricia Godwin

Patricia has many years of experience as a content writer on various subjects, but her first love is gardening. She’s never met a plant she didn’t like and, consequently, she writes about every type of plant you can think of. Once an avid gardener with a herb garden, a succulent rockery, and a rose garden – to mention a few. Nowadays, she’s constantly on the move searching for interesting plants to bring to your attention; and explain to you all the details you need to grow, care and maintain these plants.

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