One of the pressing concerns of this new decade will be water scarcity.  Countries such as Australia are preparing for so called “Day Zeros”, when water is predicted to run out. Turning off the tap while brushing teeth and showering less often are small ways we can help make a big difference. However, tackling the hidden water costs behind the products we consume is a more impactful way to help. 

Closeup of crops with sprinkler irrigation; highlighting water scarcity and the benefits of hydroponics
More than half of global freshwater is used in farming; hydroponic growing systems can save and recycle water

Over 70% of global freshwater is currently used for agriculture, meaning that farmers must quickly adapt to a water scarcity. Hydroponic systems are becoming increasingly popular, as they significantly reduce the need for water throughout the growing process. Hydroponic systems also allow for recycling of water, making them economic and environmentally-friendly.

Hydroponics can save up to 62% water in a growing setup, but not all hydroponic systems are equal. In this article, we’ll discuss the drawbacks of using rockwool growing plugs in hydroponic setups. We’ll offer a greener alternative, showcasing new innovative systems that help conserve water and protect overall health.


What is a hydroponic growing system? 

Hydroponic growing systems can vary greatly, but they all are methods of growing plants without soil. In this method, plants must receive all the nutrients they need through water instead.

While roots absorb essential nutrients, the plant itself needs to be supported and anchored. The industry solution is what is known as a plug. The different materials that the plug is composed of make a huge difference in the quality and rate of plant growth.


Lettuce growing out of a starter plug in a hydroponic growing system
Plant roots don’t require soil, but they do need a substrate to anchor and support their growth.

What makes a good plug?

In recent articles, we’ve discussed in detail what makes good soil. While hydroponic growing eliminates the soil, many of those lessons still apply. pH is still of utmost importance to growers, in addition to proper aeration and water retention.

Growing plugs are typically composed of materials that mimic soil. These materials can either be inorganic or organic. 


Inorganic Hydroponic Substrates

While gravel and sand were once the most popular inorganic substrates, rockwool is the most commonly used today. Unlike other inorganic substrates, rockwool plugs have properties typical of organic substrates.

Rockwool is derived from a mixture of volcanic rock, limestone, and coke (baked coal). It is heated to 1500 and 2000 degrees Celsius, creating tiny fine fibers that are spun into what we know as rockwool. Under these extreme conditions, near irreversible chemical bonds form. 

The Pros of Rockwool

Rockwool has great water holding capacity, while maintaining aeration and facilitating plant growth. It is naturally sterile, and thus less susceptible to the spread of disease-causing microbes. Due to the irreversible bonds, rockwool does not breakdown over time. This allows rockwool to be reused in subsequent crops

Lettuce growing in a hydroponic system with roots below substrate
Hydroponic substrates can be inorganic, like rockwool, or organic. Both have pros and cons in growing systems.


The Dangers of Rockwool

Not Biodegradable

Reusing rockwool is a great way to recycle materials in a growing system. However, on a large scale, disposal can be difficult. Even if rockwool is broken down to its fiber form, just like certain plastics, it is here to stay. Rockwool simply isn’t biodegradable. 

Rockwool is currently disposed of in landfills in developing and developed countries, despite concerns of increasingly limited space. There are recycling programs available in the industry, but they are few and can be expensive. 

“A large producer with 1,000,000 square feet of grow space can use as much as 60, 40ft shipping container loads of rockwool each year. This results in substantial disposal fees for producers and landfills taking in materials that will never biodegrade or break down.” – Matt Stromsten, BlueSky Organics

Negative Health Impact

Due to its inability to fully breakdown, rockwool fibres eventually make their way into our ecosystem. This is similar to microplastics, which are showing significant impact on soil as well as animal and human health. In a 2012 study, rockwool was determined, among popular growing mediums to have the highest impact on human health

Not Sustainable

Another disadvantage of rockwool is the amount of energy required for its production. Rockwool is manufactured all around the globe, often using non-renewable energy sources. This, along with the cost of extraction of starting materials and transportation, contributes to rockwools large carbon footprint.


hydroponic growth system with an organic alternative to rockwool
Organic hydroponic substrates, like peat or coconut fibre, offer a more eco-friendly alternative to inorganic.

Organic Hydroponic Substrates

As a greener alternative to inorganic substrates, plugs made from organic substrates and biodegradable and behave more like soil. Three of the most common organic substrates are coconut fiber (coir), peat, and sphagnum moss.

The Pros of Organic

Organic substrates contain naturally occurring nutrients, and act as buffers in maintaining a better nutrient balance. These plugs promote beneficial microbial growth more easily than the sterile inorganic alternatives. They also naturally contain growth stimulants such as humic acid and are less reliant on nutrient additives. 

Organic plugs can be smaller in size due to their ability to be compressed, and have a natural ability to hold more water.

Hydroponic Growing System closeup of starter cube with seedling; these systems can be organic or inorganic like rockwool
Organic starter plugs are the best choice for sustainable hydroponic growth, when properly sourced and constructed. The right structure and composition is needed to avoid organic contamination of a hydroponic system. This will also prevent water-logging of the substrate.

The Cons of Organic

The strong ability of organic substrates to hold moisture means that these plugs easily become waterlogged. This can affect the cycling of nutrients throughout the system. Peat substrates also lose composition over time, which can lead to system clogging in a hydroponic setup.

Having combinations of organic substrates, along with different processing methods, can overcome many of these issues and create excellent growing mediums. Being derived from organic materials, these growing mediums are usually non-toxic and better for the environment. 


BlueSky Organics Eazy-Grow System with a tomato plant growing in the organic substrate, an alternative to rockwool
The BlueSky Organics Eazy-Grow System is a combination of plugs, blocks and pyramids in custom sizes, blends and even porosity to suit your growing operation.

What BlueSky Organics Can Offer 

BlueSky Organics has partnered with Dutch Horticultural Professionals (DHP) to solve the current rockwool problem in Canada. The desire for a sustainable alternative has led to the development of an innovative new growing medium, made of compostable, recyclable, and eco-friendly materials. 

This medium originates from the Dutch Center of Cultivation Technology, where the Eazy-Plug system was born. Eazy-Plugs have predetermined pH and EC values, creating a self-regulating growing medium with an ideal air-to-water ratio. 

Sustainable, Soil-Free Growing

Newly launched in Canada, Eazy-Plug is a part of the Eazy-Grow System. This system offers a full-cycle, sustainable growing solution containing plugs, blocks and pyramids in custom sizes.

The Eazy-Grow system is highly customizable, with tailored blends and porosity to suit your crops. The unique air-pruning effect eliminates the need for pots or sleeves, while promoting optimal plant growth.

Eazy Grow System icons for eco-friendly, recyclable, and compostable; this system is a sustainable alternative to rockwool

 This easy-to-use system allows for maximum efficiency and yield, without sacrificing crop quality. Considering the cost savings, reduced environmental impact and significantly lower water requirement, the choice is Eazy