How Biochar Makes Your Garden Thrive: Water, Nutrients, Habitat

Daniel Bechtoldt
A proof-of-concept Pi Biochar Fire pit with burning corn stalks, used to create biochar.

Pictured above: A proof-of-concept Pi Biochar Fire Pit with burning corn stalks, used to create biochar.

Updated on: May/20/2024

How Biochar Makes Your Garden Thrive: Water | Nutrients | Habitat

Are you trying to make your garden even more lush and vibrant than it already is? Or are you struggling with lackluster plants and disappointing harvests? The secret to a truly thriving garden lies beneath the surface – in your soil. That's where biochar comes in, the earth-friendly upgrade that will revolutionize the way you garden.

Want to make your own biochar? Click here

Biochar: Charcoal That Helps Your Garden to Thrive

Let's break down the basics. Biochar may sound fancy, but it's simpler than you think. It's a special kind of charcoal created specifically for gardening magic. Instead of tossing wood scraps and yard waste into your green bin, you can make biochar, transforming your waste into a powerful soil amendment.

Here's how it works: Organic materials (think branches, leaves, corn stalks, etc.) are burned in a low-oxygen environment. This process, called pyrolysis, transforms organic materials into a long-lasting soil amendment – biochar!

Why Biochar Will Make Your Plants Healthier

Biochar is to a garden as a good night's sleep is to a person, revitalizing and restoring energy for the day ahead. So you can have a healthier garden.

Rainbow pink flowers in bloom. 

Rainbow pink flowers (Dianthus chinensis) blooming in my neighbor's garden, a perennial plant with pink flowers, native to China and surrounding regions. Biochar can help all your plants including your flowers thrive. 

Biochar: The Soil Sponge You Didn't Know Your Plants Needed

A colorful drawing of various vegetables growing directly out of a sponge, illustrating the sponge-like properties of biochar, which holds water and nutrients for plants to thrive.

Biochar acts like a sponge in your soil.

For many gardeners, battling the elements to ensure their plants receive the perfect amount of water can be a constant struggle. Sandy soils drain too quickly leaving plants parched. Clay soils, on the other hand, can become waterlogged suffocating roots. But there's a superhero in the world of soil amendments that can tackle both these problems -- biochar.

Biochar's secret weapon lies in its remarkable structure. Imagine a vast complex of microscopic apartments, all with incredible surface area. These countless pores within biochar make it a champion of moisture management:

  • The Super Sponge: Biochar acts like a sponge. As water passes through the sandy particles, biochar's pores capture and hold onto it. This creates a reservoir of moisture readily available for plant roots to access, even during dry spells. Your soil is able to hold more water after biochar has been added. This is particularly beneficial in sandy soils, where water can quickly drain away. [5]

  • Improved Water Infiltration: Biochar's structure doesn't just hold onto water, it also improves how water moves through the soil. In compacted soils, water can struggle to penetrate, leading to runoff and thirsty plants. If you have a lot of clay in your garden's soil, this is likely affecting your plants' growth. Biochar helps water to infiltrate the soil more easily and reach plant roots rather than running off. [6]

  • Reduced Evaporation: Hot sunny days can cause rapid evaporation from the soil surface. Biochar's presence helps to mitigate this by creating a physical barrier. The pores within biochar hold onto water molecules, reducing their exposure to the sun and air and slowing down the rate of evaporation. This translates to less water lost to the atmosphere and more water available for your plants. [2]

By acting as a sponge, improving infiltration, and reducing evaporation, biochar helps to maintain healthy moisture levels in your soil so that your garden can thrive. This not only benefits your plants by ensuring a consistent water supply, but it also can reduce how often you need to water your garden or prevent your plants from wilting when you go away on that long weekend. 

Biochar: A Magnet for Valuable Nutrients

A red, U-shaped magnet is covered in blooming flowers and green vines. This symbolizes how biochar, a type of charcoal, attracts and holds onto nutrients in the soil, just like a magnet.

Biochar transforms your soil into a magnet for nutrients. 

Healthy plant growth relies on a constant supply of nutrients. Unfortunately, these nutrients can easily be lost from the soil through leaching, volatilization (evaporation), and decomposition. But fear not, green thumb warriors! Biochar emerges once again as a champion, this time for its remarkable ability to retain nutrients within the soil, making them more readily available for your plants. Let's delve into the fascinating science behind biochar's nutrient holding prowess:

  • The Cation Exchange Powerhouse: Biochar boasts a high cation exchange capacity. Imagine cation exchange capacity as a series of tiny magnets within the biochar. These magnets attract and hold onto positively charged ions (cations), which include essential plant nutrients like ammonium (NH₄⁺), potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺). By attracting and holding these cations, biochar prevents them from leaching out of the soil with water. This creates a reservoir of readily available nutrients that your plants can access as needed. [3]
  • Adsorption Champion: Biochar isn't just a magnet for cations; it also actively attracts and holds onto certain nutrients through a process called adsorption. Specific functional groups present on the biochar surface act like sticky spots, grabbing hold of nutrients like phosphorus (P) and preventing them from becoming unavailable to plants. This adsorption process ensures a steady supply of these vital nutrients for optimal plant growth. This nutrient holding capacity is a bit more general than cation exchange capacity, because it can also apply to anions (negatively charged ions), organic molecules, and other substances. [7]
  • Surface Area Superstar: Biochar's impressive surface area plays another crucial role in nutrient retention. Remember that tiny apartment complex pore structure we mentioned earlier? This vast network of tiny pores provides an ideal habitat for beneficial microbes and fungi that live in the soil. These organisms play a vital role in breaking down organic matter and releasing nutrients for plant uptake. Biochar's porous structure offers a safe haven for these microbes, promoting their growth and activity, ultimately leading to a more efficient nutrient cycle within your soil. [7]

By acting as a cation exchange capacity powerhouse, providing a haven for beneficial microbes, and actively adsorbing nutrients, biochar creates a more efficient and sustainable nutrient management system within the soil. This translates to healthier plants that require less frequent fertilization, saving you money while leaving your garden looking great. 

Biochar: A Microscopic Metropolis for Microbes

A miniature city, that serves as a visual analogy for the porous structure of biochar that acts like a bustling metropolis, providing habitat for beneficial soil microbes.

Biochar provides a tiny (well managed) city to all the little microbes living in your garden.  

The hidden world beneath our feet – the soil – is teeming with life. Microbes, including bacteria, fungi, and protozoa, play a critical role in maintaining healthy soil and promoting plant growth. But did you know that biochar can act as a tiny metropolis, attracting and supporting these microbial communities? Let's explore some of the ways biochar fosters a vibrant and thriving microbial world:

  • A Community with High Porosity: Remember biochar's tiny apartment complex structure? Those countless tiny pores within biochar are more than just moisture reservoirs. They also provide a haven for a diverse community of microbes. Biochar's porosity allows for better air circulation and oxygen availability, while maintaining high surface area, creating ideal conditions for these vital organisms. Think of it as a network of well-ventilated apartments where microbes can thrive. [7]

  • More Nutrients Means Better Habitat: We previously discussed biochar's impressive adsorption and cation exchange capacity. This ability to hold onto nutrients isn't just beneficial for retaining nutrients for plants, it also improves habitat for soil microorganisms. By attracting and holding onto essential plant nutrients like calcium (Ca²⁺) and magnesium (Mg²⁺), biochar ensures a readily available supply of these elements crucial for microbial growth and activity. [7]

  • Reduced Pathogen Pressure: Biochar can play a role in suppressing harmful soilborne pathogens. Biochar has several tricks up its sleeve for reducing pathogen pressure.  Firstly, biochar can adsorb toxins produced by pathogens, reducing their harmful impact on plants. [4] Secondly, by creating a more hospitable environment for beneficial microbes, biochar indirectly promotes microbial abundance and diversity, making it harder for pathogens to establish themselves and cause disease in your garden. [1]

By providing habitat, facilitating nutrient access, and providing conditions that are less favorable to pathogens, biochar fosters a thriving and diverse microbial community within your garden’s soil. This increase in microbial activity translates to a number of benefits that leads to healthier and more productive plants in your garden. 

Make Your Own Biochar!

Did you know you can make biochar while enjoying a backyard fire pit? Here at Pi Fabricators, we're passionate about helping gardeners create amazing biochar enriched soil. That's why we created an innovative and stylish biochar fire pit. Enjoy relaxing evenings by the fire, and harvest biochar to enrich your garden! Who knew backyard fire pits could be so productive?

Click here to learn more about the Pi Biochar Fire Pit.


Works Cited:

  1. Amit, Jaiswal K., et al. “Linking the Belowground Microbial Composition, Diversity and Activity to Soilborne Disease Suppression and Growth Promotion of Tomato Amended with Biochar.” Scientific Reports, vol. 7, no. Article: 44382, 2017,
  2. Feng, Weiying, et al. “Effects of biochar on soil evaporation and moisture content and the associated mechanisms.” Environmental Sciences Europe, vol. 35, 2023, Article Number: 66. SpringerOpen,
  3. Hossain, Zahangir, et al. “Biochar and its importance on nutrient dynamics in soil and plant.” Biochar, 2020, [Note: as of May-20-2024 the full PDF of this document is available to the public for free from ResearchGate,]
  4. Iacomino, Giuseppina, et al. “The Suppressive Effects of Biochar on Above- and Belowground Plant Pathogens and Pests: A Review.” Plants, vol. 11, no. Article: 3144, 2022,
  5. Li, Ling, et al. “Role of Biochar in Improving Sandy Soil Water Retention and Resilience to Drought.” Water, vol. 13, no. 4, 2021, p. 407,
  6. Novak, Jeff, et al. “Biochars impact on water infiltration and water quality through a compacted subsoil layer.” Chemosphere, vol. 142, 2016, pp. 160-167. Science Direct,
  7. Tomczyk, Agnieszka, et al. “Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects.” Reviews in Environmental Science and Bio/Technology, vol. 19, 2020, pp. 191-215,


Additional Resources:

The International Biochar Initiative:

Ithaka Institute:


About the author

Hi, I'm Daniel Bechtoldt, a mechanical engineer. I'm passionate about using biochar to improve soil health and maximize harvests. When I'm not spending time with my family or finding solace in nature, I'm developing innovative biochar and tool storage solutions for people like you.


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