Substrate Sustainability Uncovered

Why Reusability—and a Holistic LCA—Matters in Sustainable Product Design

The Hidden Costs of Growing Media: Why a Holistic LCA Matters

At GyroPlant, sustainability is more than a buzzword—it’s the foundation of our values. As we help growers replace peat and other extractive single-use substrates in horticulture, we’ve learned that the true environmental story is far more complex than a simple “peat vs. alternatives” debate. That’s why we use Life Cycle Assessment (LCA) not just as a box-ticking exercise, but as a lens to examine every stage and impact of our organisation. Here’s why a holistic approach—and a critical look at all substrate choices—is essential for real sustainability.

What is a Life Cycle Assessment (LCA)?

An LCA is a scientific method for evaluating a product’s environmental impacts from raw material extraction through manufacturing, transport, use, and end-of-life. It covers multiple categories, including (but not limited to):

Climate Change (Carbon Footprint): Greenhouse gas emissions.

Resource Depletion: Use of finite resources like minerals and fossil fuels.

Land Use and Biodiversity Loss: Impact of land conversion and habitat destruction.

Water Use and Scarcity: Freshwater consumption and pollution.

Toxicity (Human & Ecological): Harmful chemicals released to air, water, and soil.

Eutrophication & Acidification: Nutrient pollution and acid rain potential.

Circularity & End-of-Life: Recyclability, compostability, and landfill persistence.

A truly sustainable product must perform well across all these categories—not just one.

The Pitfalls of Peat, Coir, Rockwool, and Bioplastics:

Peat: The Classic Culprit

Peatlands are among Earth’s best carbon sinks, but peat extraction releases huge amounts of CO₂ and destroys unique habitats. Drained peatlands can take thousands of years to recover, and the loss of biodiversity is often irreversible. This is why many countries are phasing out horticultural peat.

Coir: Not as Clean as It Seems

Coconut Farm

Coir, made from coconut husks, is often marketed as a sustainable, renewable alternative. But:

• Ecosystem pressure: Expansion of coconut plantations has contributed to deforestation and the loss of delicate natural ecosystems in parts of India, Sri Lanka, and Southeast Asia. Even if only a small percentage of forests are lost, the cumulative effect on biodiversity can be significant.

• Soil and nutrient depletion: Exporting coir removes organic matter from local soils, increasing reliance on synthetic fertilisers.

• Water pollution: Processing coir is water-intensive and produces salty, contaminated runoff.

• Contamination risks: Poorly processed coir can contain salts, pathogens, or plastic contaminants.

• Social and ethical concerns: Labor practices and local community impacts are often overlooked.

LCA blind spot: Many LCAs focus on carbon, missing water use, pollution, and social impacts.

Rockwool: Durable, But At What Cost?

Rockwool is valued for its sterility and consistency, but:

• High energy demand: Manufacturing requires melting rock at 1,500°C, leading to high carbon emissions.

• Non-biodegradability: Rockwool persists in landfill for centuries, with limited recycling options.

• Potential health risks: Fine fibres can pose risks to workers and the environment, and in your home if being used for home use SMART gardens.

LCA blind spot: Persistent landfill impact and micro-fibres are rarely fully accounted for.

Bioplastics: Circular Promise, Real-World Challenges

Bioplastic-based substrates, from crops like corn or sugarcane, promise sustainability but face real issues:

• Land use and biodiversity: Crop expansion for bioplastics can drive deforestation and habitat loss.

• Industrial composting required: Many bioplastics only break down in specific facilities.

• Toxic additives: Some contain chemicals that may leach into the environment.

• Resource competition: Using food crops for substrates can compete with food supply.

LCA blind spot: Land use change, biodiversity loss, and chemical leaching are often out of scope.

Why Reusability is a Key (But Not the Only) Solution:

Reusability is a powerful tool in sustainable design. Our GyroCup, for example, is engineered for long-term use, reducing waste and spreading its environmental “cost” over many cycles. This helps conserve resources, lower total carbon footprint, and support a circular economy.

But reusability isn’t automatically better. The product must be robust, easy to clean, and actually reused enough times to offset its initial impact. Cleaning, transport, and eventual disposal must be managed efficiently, or the benefits can be lost. Sometimes, a poorly designed reusable product can have a higher impact than a well-designed single-use option if it’s not used enough or is energy-intensive to maintain.

The Limits of LCA—and Why We Go Further

While LCA is an essential tool, it has its limitations:

• Narrow boundaries: Many LCAs focus on carbon and water, but overlook biodiversity, social equity, and persistent waste.

• Data gaps: Localised impacts (like water scarcity or peatland destruction) may be invisible in global averages.

• End-of-life and circularity: The fate of substrates after use, especially in landfill, is often underestimated.

• Social and ethical factors: Worker rights and community impacts are rarely included.

That’s why at GyroPlant, we use both internal and independent LCA research—including collaboration with the University of East London—to guide our design and sourcing. We focus on reusability, circularity, and transparency, aiming to avoid simply swapping one environmental problem for another.

The Real Kicker:

Many of these so-called sustainable substrates arrive at hydroponic setups packaged in single-use plastic trays, shrink wrap, or polystyrene boxes—materials that often end up in landfill or incinerators after just one use. This packaging isn’t just an afterthought; it can skyrocket both emissions and waste, sometimes exceeding the footprint of the substrate itself. The environmental cost of producing, transporting, and disposing of all that plastic is rarely included in headline sustainability claims. So, when comparing growing media, it’s not just about what the substrate is made from, but also the hidden impact of all the materials and packaging used throughout the supply chain. True sustainability means looking beyond the core product to the full ecosystem of resources that get a plant from factory to farm.Our Internal LCA and Academic Partnerships

At GyroPlant we see the importance of assessing impacts from cradle to grave—including raw material extraction, manufacturing, transport, use, and end-of-life. We identify “break-even points” for reusables and optimise for durability and efficiency. It changes from farm to farm. Although its easy to slap a marketing figure of 90% less Carbon compared to other substrates, we like to work with farms to produce accurate information beyond Carbon.

We also collaborate with the University of East London (UEL), whose research on peatland restoration and circular systems helps validate and refine our approach. UEL’s work shows that even degraded peatlands can become carbon sinks again, reinforcing the urgency of moving away from extractive substrates and toward true circularity.

The Takeaway

No single growing medium is perfect. The key is to consider the full spectrum of impacts—not just carbon footprint. By looking at the whole life cycle, including hidden and out-of-scope damages, we can make better choices for people and planet.

When choosing or designing a growing medium, ask not just “What’s the carbon footprint?” but “What are the hidden costs to ecosystems, water, waste, and people?” Only then can we grow in a way that truly respects the planet.