How much biochar do I need for my garden beds?
We recommend you use ideally 10 litres of biochar per square metre for intensively managed garden beds, although you will still see improved results with 5 litres per square metre.
For example, if your garden bed is 3 metres long and 1.2 metres wide, you would want to use between 5x3x1.2 = 18 litres and 10x3x1.2 = 36 litres.
We include a "how to" guide with every biochar order, but it's useful to read this guide too
How much biochar do I need for my compost or worm farm?
Have a look at our cool composting guide by clicking here
What's the difference between biochar, agricultural charcoal, horticultural charcoal, activated carbon, charcoal and biocoal?
The main difference is its end use:
- Biochar's final destination is in the soil or other carbon sinks. This happens via direct application as a soil amendment, or through being fed to animals which then leave droppings on the soil, or by being included in other materials such as concrete, asphalt or more exotic materials. Biochar is made from biomass (usally wood, but can include anything that was once alive)
- Agricultural and Horticultural charcoal is a form of biochar that has been optimised for use in their respective applications. These biochars should have low or no heavy metals and other contaminants such as plastics.
- Activated carbon is carbon that has been 'activated' with steam or chemicals to increase surface area and reduce the mineral content of the material, leaving a much higher percentage of carbon in the material. Activated carbon can be made from fossil fuel or biomass sources.
- Charcoal is carbon-rich material that is used as either a fuel or a reductant. Charcoal is made from biomass, like biochar
- Biocoal / biocarbon is a charcoal that is made from biomass. Torrefied wood is a form or biocoal
Biochar will have reached at least 380 degrees Celsius during production to start driving off any volatile substances such as creosotes and tars from inside the biomass, leaving a spongy carbon lattice. The best quality biochars for growing are made at over 500 degrees Celsius. At Char Bro, our biochar is all made at over 500 degrees celsius.
Biocoals and charcoals from wood are often made at temperatures lower than 380 degrees and leave in some creosotes and tars to help make lighting the coals easier. It is not recommended to use untested biocoals or torrefied wood for agricultural or horticultural applications because of the risk that these creosotes and tars may present a risk to your animals and plants.
What's the price of biochar in NZ?
Let's be honest here
Biochar usually just looks like black pieces of dirt or charcoal. So how can you tell what's best for what you want to do?
Firstly, it's useful to think of biochar as a category of products because biochar products are not all created equal, and so they have different prices to reflect that. Biochar can also be custom made for a specific purpose as well as mixed with other ingredients to get best results for what you want to achieve.
Factors Influencing Biochar Prices
There are many factors that influence the price of biochar in New Zealand. The key factors that influence the price of biochar are:
- availability, location and price of raw materials
- what else is produced with the biochar, and whether those co-products can be sold
- whether there are special things you want your biochar to be able to do
- the volume, and consistency of demand for specific biochar and co-products
- regulatory requirements
With all of these factors, the price of biochar can vary from hundreds of dollars to thousands of dollars per cubic metre.
What is encouraging is that biochar is being bought by people all across New Zealand. With the right advice, these people's investments in biochar break even in a matter of weeks, or a few months.
Biochar Buyer Guidance
Let us help take the guesswork out buying of biochar so that you get best value with biochar, and that your biochar is There For Good, not just pretty black dirt.
How do I use biochar in my compost?
Biochar and compost were made for each other. Simply mix in biochar at 10% as you make your compost pile, then compost as you normally would, or have a look here for a more in depth look. Nature will do the rest! You can also check out this in depth guide from our friends at Massey University on the International Biochar Initiative website. For expert composters - our biochar will have a C:N ratio of about 100:1
How can I charge and inoculate biochar?
Char Bro recommends pre "charging" biochar as well as inoculating it with beneficial soil life. Without charging first, raw biochar can compete with plants for nutrients and stunt growth. There's lots of ways to do it, but this excellent paper spells out the main principles for you. There are ways to optimise your growing by using the best combinations of selected biochar, nutrients and soil life for your crop. Contact Char Bro for advice on what can work well for your plants.
What soils does biochar work best with?
Biochar works best with soils that have low organic matter content (pale coloured soils), and does really well with sandy soils because it can help increase moisture, soluble nutrient retention
Biochar also works well when mixed into clayey soil because it helps to open up the soil, helping to get the right amount of air and water to your plants.
Biochar also helps silty and loam soils which are low in organic carbon, and is a carrier
of nutrients and home to beneficial microbes.