Biochar Basics
How does biochar benefit my garden?
- Improved Soil Structure: Biochar can improve soil structure by increasing its water-holding capacity and aeration.
- Nutrient Retention: It can help retain nutrients in the soil, reducing nutrient runoff and fertilizer needs.
- Enhanced Microbial Activity: Biochar can provide a habitat for beneficial soil microorganisms, which can enhance plant growth.
- Reduced Soil Acidification: It can help neutralize acidic soils and maintain optimal pH levels.
How can biochar help the environment?
Carbon Sequestration. By storing carbon in the soil, biochar can help mitigate climate change.
How can I use biochar in my garden?
- Soil Amendment: Mix biochar into your garden soil before planting.
- Top Dressing: Apply a layer of biochar to the soil surface as a mulch.
- Potting Mix: Incorporate biochar into your potting mix for container gardening.
Are there any drawbacks to using biochar?
Biochar can be expensive to buy. Fortunately you can make your own biochar in your backyard while enjoying your Biochar-Making Fire Pit.
Making Biochar
What makes the Biochar-Making Fire Pit different from traditional fire pits?
The Biochar-Making Fire Pit prevents air from entering from the bottom of the fire pit which allows biochar to form without being completely burned up. Its tapered shape allows enough air to come in from the top to keep the fire burning.
Is it hard to make biochar?
With the Biochar-Making Fire Pit making biochar takes similar skills as using any fire pit. There is slightly more skill involved to feed the fire and let it burn down but it is simple enough to successfully make biochar on your first try.
Why does the Biochar-Making Fire Pit have a hose attachment?
We included a bottom up quenching pipe to make quenching biochar cleaner (virtually no ash dust like when quenching from the top) and to allow the quench water to be easily and cleanly drained through your garden hose.
How does the Biochar-Making Fire Pit reduce smoke?
The Biochar-Making Fire Pit features a top-down airflow design that creates a powerful vortex. This mechanism draws smoke back into the flame to be re-burned, resulting in a significantly cleaner and more efficient fire.
Biochar-Making Fire Pit Care & Durability
Will the fire pit crack or develop metal fatigue over time from repeated use?
Metal fatigue really isn’t a concern with these — a wood fire doesn’t produce the kind of stress cycling that causes fatigue cracking in steel. Our design helps too: the edges are lapped and double welded, so there’s no thin single-layer seam that would be a weak point. You could burn this every weekend and fatigue wouldn’t be what gets it.
How long will the fire pit last, and what causes it to wear out?
What does wear on a steel fire pit over time is rust, and that comes from two things: the high-temperature oxidation during each burn (that flaky black scale you see is a tiny bit of steel being converted), and regular old moisture corrosion between burns from rain and humidity. Of the two, moisture between burns is by far the bigger factor. The pit is 16 gauge carbon steel — that’s about 1/16” thick, which is heavier than many fire pits you’ll find. Even with no care or maintenance and leaving it outside you’d get a solid 10–15 years out of it before rust became a structural concern. The single worst thing you can do is let rainwater sit in the bottom between uses — that’ll shorten the life more than anything else. A couple easy things to get the most out of it: keep it covered or under a roof between uses, and clean the ash out when you can since ash holds moisture. Do that and this thing will last you a very long time.
What do you recommend for preventing rust on the outside of the fire pit?
If you prefer a painted finish over a rustic patina we recommend Rust-Oleum High Heat Ultra. It’s a rust-preventive enamel that maintains a rich semi-gloss sheen even after repeated heating and withstands temperatures up to 1,200°F (648°C). Apply it only to the exterior of the fire pit — it should not be used in areas directly exposed to flames (like the inside of the pit) or on the cooking grates. No primer is needed for this particular spray.
Can the fire pit be covered to use as a table when not in use?
We don’t currently make a dedicated tabletop lid, but the fire pit is designed so that two of our griddles fit side-by-side on top. While they’re cooking surfaces, placing two of them on the unit effectively covers the opening and creates a full flat surface when the fire pit is not in use.
Biochar Storage - Application
What time of the year should I make biochar?
You can make biochar any time of the year. Just check with your local authorities to make sure backyard fire pits are allowed and avoid making biochar when the fire danger is high.
How long can I store biochar after I make it?
Biochar, assuming it doesn't catch on fire, will stick around for more than 1000 years so you can store it as long as you want. Inoculated biochar also does not have a shelf life so it can be stored also as long as you want.
Where can I store biochar before I add it to my garden?
Store in an area that does not have the risk of introducing contaminants (E.g. motor oil, plastic, chemicals, etc.) You could simply pile biochar in your garden but if strong winds are a possibility it may be required to cover up your biochar.
Alternatively, you can mix it into your compost pile and allow it to sit until the compost is ready for application in your garden.
Charging Biochar With Nutrients (Inoculating)
Should I charge my biochar with nutrients right away or wait to charge it in the spring before planting?
If you compost I would add biochar directly to your compost as you make it as long as you are not making so much compost that the biochar exceeds 50% of the volume of your compost pile. After a month in your compost the biochar will have been inoculated with nutrients and microbes giving the biochar (and your garden) a head start for your next growing season. You can add the biochar compost mixture to your garden as you fill up your compost bin. Note that for the long term benefits of biochar (and some of the short term benefits) inoculating your biochar is not necessary.
What can I use to inoculate my biochar?
Composting with about 50% by volume in your compost for a month is an excellent way to inoculate your biochar. This adds nutrients and microbes to the biochar over time and is a free source of nutrients. Other sources of nutrients and microbes include manure, worm castings, worm/compost tea, mushroom soil. Really any source of nutrients and biological activity will help biocharge your garden.
Will the biochar freezing kill off beneficial microbes?
Soil microbes are naturally adapted to local freeze-thaw cycles, possessing a high degree of freeze tolerance. Therefore, if inoculated biochar freezes, the surviving populations will be hardy and well-adapted to your specific climate. However, microbial activity slows down significantly in cold conditions, which, in turn, prolongs the inoculation process.
To dramatically accelerate this 'charging,' inoculate the biochar within an active compost pile. The heat generated by the composting materials sustains elevated temperatures, ensuring high microbial activity and rapid biochar saturation.
Do I have to inoculate my biochar?
Direct application of uncharged biochar provides immediate benefits to your garden, primarily through improvements in soil structure and moisture retention.
For instance, in highly managed environments like raised beds—where nutrient levels are sufficient but rapid drying is an issue—the initial addition of uncharged biochar has shown clear success. Amending the soil with biochar resulted in significantly healthier plant growth (such as tomatoes) compared to unamended control groups, illustrating its quick and positive impact on water management.
However, this strategy changes based on your soil's limitations: If nutrient scarcity (e.g., nitrogen deficiency) is the primary problem in your soil, you will achieve much better results in the first growing season by inoculating/charging your biochar prior to application.
Will biochar that has not been inoculated sponge up, and lock away nutrients and microbes lowering my garden's growth.
If your plants are primarily constrained by existing nutrient scarcity, applying uncharged biochar carries a potential risk: the biochar may temporarily immobilize or 'sponge up' some available nutrients (often nitrogen) in the first year. This phenomenon, known as nutrient draw-down, could potentially suppress initial growth.
While our personal experience has not shown adverse effects from uncharged biochar in the first season, skipping the inoculation process means forfeiting the significant growth improvement that charged biochar offers immediately.
Regardless of whether you initially inoculate, your soil's native microbial community will naturally charge the biochar over several years. Once this process is complete, the biochar is fully activated, providing its complete range of benefits—including enhanced nutrient retention and water holding capacity—to your garden for generations.