Biochar: A High-Performance Alternative to Perlite

November 11, 2025

For decades, perlite has been a trusted material in horticulture, agriculture, and soil restoration. Its lightweight, porous nature has long made it a reliable choice for improving drainage and aeration.

But as growers increasingly seek sustainable, high-performing, and cost-effective alternatives, perlite’s limitations are becoming hard to ignore. It is a non-renewable, costly, and energy-intensive material to produce, with performance that can no longer compete with innovative solutions such as biochar.

Biochar is a carbon-rich, renewable material made from organic residues through controlled pyrolysis. While small-scale artisanal production has existed for years in North America and Europe, Airex Energy is proud to have brought to market a breakthrough solution using our proprietary technology CarbonFX-HT, that enables industrial-scale biochar production from a wide range of feedstocks. This process delivers a homogeneous, high-quality biochar designed to meet the performance and consistency the market has been waiting for.

For years, scientific studies have shown that biochar can replace perlite entirely or partially in growing media, providing the same drainage capacity while delivering superior results in plant growth, nutrient retention, and soil health.

As perlite prices fluctuate due to global market conditions, biochar offers a stable, local, and renewable alternative that helps growers increase yield while reducing costs and environmental impact.

Biochar vs Perlite: A Comparison

Below is a summary of the key differences between perlite and biochar to highlight why biochar represents a better long-term investment for growers and substrate producers.

The first table compares the environmental profiles to showcase how biochar provides a more sustainable and carbon-efficient alternative.

Environmental Profile
Feature	Perlite	Biochar
Origin	Extracted in mines from volcanic glass (Greece is the largest exporter)	Can be produced locally from biomass residues
Sustainability	Non-renewable	Renewable
Environmental Impact	High Mining extraction, Heating processing, Transportation, etc	Low Carbon-negative process using agricultural waste, woody residues, or other waste
Energy-intensive	High Thermal expansion process at >900 °C using fossil fuel and emitting CO₂	Low Producing biochar using the self-generated energy from the pyrolysis process
Carbon sequestration	None	High 1 ton of biochar can sequester up to 3 tons of CO₂

The table below compares the key performance characteristics of perlite and biochar, highlighting how biochar offers superior biological activity, stability, and water retention.

Performance Characteristics
Feature	Perlite	Biochar
Weight	Lightweight	Lightweight
Aeration / Drainage	High	High
Microbial Support	Minimal	Major Promotes micro-organism activity
Biological Activity	None Inert	High Promotes microbial life making healthier & stronger root systems
Water Holding Capacity	Moderate to High	High Biochar retains moisture longer especially if made from woody residues
pH Regulation	Neutral Might require lime	Natural pH buffer Reduces lime input
Structural Stability	Compacts over time	Long-lasting porosity Longer substrate lifespan

Proven by Science:
5 reasons why Biochar is the Ideal Replacement

1) Superior Plant Growth

Biochar promotes superior plant growth through multiple benefits, including improved soil structure, aeration, and water retention, while providing a stable habitat for beneficial microbes. Its high nutrient-holding capacity enhances fertilizer efficiency, leading to stronger roots and more vigorous, resilient plants.

Many studies have proven this to be the case in nurseries and greenhouse trials where plants grown in biochar-based substrates achieved higher yield than those in traditional peat–perlite mixes:

Ferlito et al. (2020) found that citrus seedlings grown in 25–50% biochar blends maintained excellent stem diameter and root development while ensuring long-term substrate stability.
A study in Horticulturae by Huang and Gu (2019), reported similar results: plants in biochar–peat mixes performed as well as or better than perlite controls, while improving water retention and nutrient availability.

2) Enhanced Nutrient Retention and Efficiency

Unlike inert perlite, biochar acts as a nutrient sponge. It keeps nutrients where they belong (in the root zone), so it reduces waste and prevents nutrient leaching.

Altland & Locke (2012) demonstrated that adding 5–10% biochar to peat–perlite mixes reduced nitrate leaching from 7.3% to less than 1%, suggesting that biochar can act as a moderator in extreme fluctuations, so nutrients can be available to the plants consistently over time.
Nemati et al. (2015) found that biochar increased cation exchange capacity (CEC) from approximately 5 cmol/kg (perlite) to up to 365 cmol/kg, significantly improving fertilizer-use efficiency.

3) Improved Water Retention and Structural Stability

Biochar’s high porosity increases soil aeration and moisture retention. While biochar is biodegradable, it decomposes extremely slowly (over 1000 years), allowing it to provide long-term benefits to soil, and therefore outperforming perlite’s main benefits such as maintaining water between irrigations.

Studies confirm these results. For example, the Huang and Gu (2019) study found that biochar-based substrates exhibited better infiltration and less compaction over time, promoting consistent oxygenation and root hydration. Simply put, with biochar, growers can reduce irrigation frequency without compromising oxygen supply.

4) Natural pH Buffering and More Fun for the Good Microbes

Biochar naturally balances pH in peat-heavy mixes, often eliminating the need for lime. Its porous, carbon-rich structure supports beneficial microbial activity, fostering a more resilient and biologically active root zone. Unlike perlite, which is inert and adds no biological value, biochar is dynamic, living, and restorative, creating an ideal environment for micro-organisms that help plants thrive at their full potential.

5) Environmental and Economic Advantages

Perlite production requires heating volcanic rock to temperatures above 900 °C, consuming large amounts of fossil energy and releasing significant CO₂ emissions. Its environmental footprint is considerable, and high transportation costs further contribute to why more growers are seeking sustainable alternatives.

Biochar, by contrast, is recognized as a carbon-negative solution. Each ton produced with Airex Energy’s CarbonFX-HT technology sequesters between 2 and 3 tons of CO₂ equivalent. From both an environmental and economic standpoint, biochar is best produced locally from biomass residues such as woody residues, agricultural waste, or municipal waste. This approach reduces transportation emissions while contributing to a local and circular economy.

In other words, biochar isn’t just a replacement, it’s a regenerative material that transforms waste into long-term carbon storage while improving soil health and plant performance.

Biochar is not just an alternative — it’s the foundation of regenerative horticulture & agriculture.

Scientific consensus is clear: biochar is a proven, sustainable replacement for perlite that offers agronomic, environmental, and economic advantages on short, medium and long term.

By integrating biochar into greenhouse and nursery substrates, growers can:

Improve plant growth and resilience
Reduce fertilizer and irrigation needs
Rebuild soil vitality
Rehabilitate compacted soils
Contribute to long-term carbon sequestration

As Veazie et al., say it well in their review study, biochar can fully replace perlite (15-30% v/v) in peat-based substrates without compromising plant growth, nutrient balance, or product quality. It will improve pH management, enhance nutrient dynamics, and ultimately, increase productivity.

To learn more about how to replace perlite with biochar, contact us here.

References

Altland, J. E., & Locke, J. C. (2012). Biochar Affects Macronutrient Leaching from a Soilless Substrate. HORTSCIENCE, 47(8), 1136–1140.
Ferlito, F. et al. (2020). Evaluation of Conifer Wood Biochar as Growing Media Component for Citrus Nursery. Applied Sciences, 10(5), 1618.
Nemati, M. R. et al. (2015). Potential Use of Biochar in Growing Media. Vadose Zone Journal, 14(11).
Huang, L.,and Mengmeng, G. (2019). Biochar as a Partial or Total Replacement of Perlite in Growing Media. Horticulturae, 5 (14).
Veazie, P., Balance, M. S., Whipker, B. E., & Jeong, K. Y. (2023). Comparison of Peat–Perlite-based and Peat–Biochar-based Substrates with Varying Rates of Calcium Silicate on Growth and Cannabinoid Production of Cannabis sativa ‘BaOx’. HortScience, 58(10): 1250–1256. https://doi.org/10.21273/HORTSCI17324-23

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