Do You Need To Add Perlite To Coco Coir?

No doubt, coco coir is one of the best growth media and soil substitutes you can ever use in your garden. Many growers hype this natural coconut fiber extract for its excellent absorption, aeration, and water retention properties. Besides, it is resistant to disease and has zero decomposition rate.

As much as coco coir has one of the most effective water retention capabilities, many growers opt to mix it with other amendments like perlite. 

What is perlite?

Perlite is a naturally occurring mineral that exists in the form of volcanic glass or ash. It boasts of high water content compared to other soil amendments. So, why should you add perlite to coco coir? Let’s find out.


Does Coco Coir Need Perlite?

No. It does not. Adding perlite to coco coir has its fair share of upsides and downsides, but the benefits clearly outweigh the few shortcomings. You will notice improved plant growth and a significant increase in yields as part of the benefits of mixing perlite with coco coir. 

Here are some of the reasons why you should consider adding perlite to coco coir:

benefits of adding perlite to coco coir

  1. Prevents stagnation

Like coco coir, perlite has excellent aeration and drainage properties. Mixing it with coco coir goes a long way to prevent stagnation by allowing excess water to drain freely.

And as you know, good aeration and drainage helps in healthy root development and allows plants to absorb 98% oxygen via the roots.

Perlite and Coco Coir
  1. Promotes water retention

Perlite is a porous mineral and it consists of many cavities that are capable of holding water like a sponge. In fact, it can hold water up to 3-4 times its weight just like coco coir.

This means, mixing it with coconut coir can greatly improve water retention and allow your plants to absorb the much-needed moisture and nutrients they require.

  1. Boosts healthy plant growth

The essence of mixing perlite and coco coir is to boost healthy plant growth. Perlite is super lightweight, meaning it won’t weigh down your plants, and this allows your seedlings to germinate and grow without any impediments.

Perlite also supports aeration and helps drain excess water away – which are essential for healthy root growth.

  1. Zero decomposition rate

While coco coir has a low decomposition rate, perlite does not decompose at all. Adding it to coco will likewise reduce its decomposition rate.

This means there is no chance of your plants developing diseases. The mixture can last for years, and you can reuse it several times with each farming cycle.

  1. Perlite is naturally-occurring

Since perlite does not contain carbon, many people don’t consider it as an organic compound.

However, this should not dissuade you from adding it to coco coir. Perlite is naturally-occurring and it is safe for use with all types of plants.

It does not contain any harmful chemicals or synthetic substances, making it ideal for your garden.

  1. Neutral pH level

Just like coco coir, perlite has a neutral pH level, but it usually takes on the alkalinity or acidity of the added compound.

For instance, if your coco coir substrate has a pH level of 5, then the perlite substrate will also take on a similar pH level. This makes it ideal for adding it to your coco coir.

Related: 4 Best Perlite for Indoor Plant

How much perlite do You add to coco coir?

The recommended amount of perlite that you should add to coco coir ranges from 10-50%. However, this depends on several factors like the type of plants in your garden, the availability of additional additives, and water retention/drainage needs. 

Coco Coir and Perlite

If you are propagating plants by cuttings, you should consider adding more perlite to coco coir up to 50% since it helps foster a better root system.

If your crops require more moisture and you want better water retention, consider adding 10-20% of perlite to your coco coir.

Adding 30-50% of perlite will also come in handy if you intend to use plenty of supplements on your farm.

The substrate will create additional pockets, allowing your plants to absorb more nutrients for faster and healthier growth.

What does perlite do to the soil?

When added to the soil, perlite improves aeration and drainage. It works by altering the substructure of the soil, making it ideal for growing plants. It also changes the texture and keeps the soil loose.

To obtain desirable results, you should mix the right ratio of perlite to soil. In any case, perlite tends to cake up if you apply too much of it.

The substrate may also affect soil quality and restrict root growth if you don’t get the ratios right.

We recommend that you rake in a 2-inch layer of perlite into 6-12 inches of soil. You may also add perlite to soil on a 50-50 ratio, depending on the type of plants you want to grow.

Can you grow plants in just perlite?

Yes – you can grow plants in just perlite without mixing it with soil or any other growing medium. Perlite makes a very good soilless growing medium since it holds water well and it allows oxygen to get to the roots of the plant effectively. 

Discover more about soilless mediums in Everything About Hydroponics.

When used as a growing medium, perlite forms several air pockets, allowing water and oxygen to move freely to the roots of your plants.

It also supports healthy root development since plants do not have to struggle too much to absorb the nutrients that they need.

The only concern is that perlite as the sole growing medium might not be ideal for all types of plants.

Perlite tends to float in excess water, meaning it may not be the right option for plants that require plenty of moisture.

You may have to mix it with peat moss or coco coir if you want to grow such types of plants.

Can you grow plants in pure coco coir?

Yes – you can grow plants in pure coco coir. However, some plants may not do very well when planted in pure coco coir because of the high salt concentration. You must first sterilize and hydrate the coconut coir before using it as your plant medium.

Sterilization of coco coir is important since it kills any disease-causing pathogens in the medium and it neutralizes the high salt content, making the coco coir suitable for growing all types of plants.

But after sterilization, you must add moisture to the coco coir for it to be ready for planting.

How do you mix coco coir and perlite?

The right mix of coco coir and perlite will guarantee healthy plant growth and give you better yields at the end of the farming cycle.

Regrettably, many growers do not know how to mix these two soil substitutes. The wrong coco coir to perlite ratio can do more harm than good, leading to stunted growth and dying crops.

Ideally, you should add 25% perlite to 75% coco coir to obtain optimum results. Some people opt to mix the two using a 1:1 (50%-50%) ratio.

Although not harmful, a 1:1 ratio means less room for other important additives.

How often do you need to water coco coir?

One main advantage of using coco coir as your growing medium is that it has excellent water retention capabilities.

This means you don’t have to water your plants every now and then. Coco coir holds enough water and nutrients, which can last for several days.

However, some plants require frequent watering no matter how well coco coir has excellent water retention properties. With this in mind, you should water such plants every 1-2 days. 

If you are growing seedlings on coco coir, then you should water them every 4 to 5 days. Too much moisture might impede the supply of oxygen to the seedlings and lead to stunted growth.

Is growing in coco better than soil?

Growing in coco is far much better than soil. Unlike soil, coco coir is lightweight and airy. This means it does not weigh down on your crops and your plants can develop larger root systems for healthier growth. 

Coco coir is also inert, meaning it does not contain and meaningful nutrients. This means you have better control over the nutrients that go into your plants.

Another advantage of using coco over soil is that it is resistant to diseases. This plant medium does not harbor pests and disease-causing pathogens.

In the end, you won’t have to use pesticides and fungicides on your hydroponic farm.

What is coco coir good for?

Coco coir is ideal for various types of plants, ranging from potted houseplants to outdoor crops.

It promotes healthy root development and you can use it as a soil additive or as a soil substitute, depending on your farming needs.

Read Coco Coir for Houseplants.

Final Thoughts

Adding perlite to coco coir promises to deliver incredible results. Using a mixture of these substrates as your grow medium of choice means better aeration, improved drainage, and guaranteed healthy plant growth. 

Since perlite does not decompose, you should expect your crops to remain disease-free throughout the farming cycle. Then again, this naturally-occurring mineral is inert, meaning it does not interfere with nutrient concentrations.

Considering what your garden stands to gain, there is no reason why you should not add perlite to coco coir.

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