News & Views in Hertford Heath

What on earth is Biochar?

What on earth is Biochar?

It's funny how many times an item pops up in the news etc once it has become fashionable. It moves from relative obscurity to part of the everyday discussion in the blink of an eye. Once such item is BIOCHAR.

Biochar is the carbon rich remains of organic material that has been heated to decompose and remove most of the hydrogen and oxygen containing molecules. The process is called pyrolysis and is carried out in the absence of air/oxygen to prevent the material burning. The resulting residue is black and contains the “skeletal” remains of the starting material e.g. wood. The finer the starting material the finer the end product.

It is carbon-rich and specifically designed for soil enhancement. You can use it to nourish your soil, enhance growing conditions and get better soil structure. The indigenous tribes of the Amazon basin have been using biochar for thousands of years as part of the process of making “terra preta” (black earth).

Every time you dig in 1kg of biochar to your soil you have helped to take 2.6kg of CO2 out of the atmosphere by burying it according to EBC Carbon Sink certification –

  • Helps to retain goodness in the soil
    Biochar has a porous structure which traps water and vital nutrients preventing them being washed away in rainfall  
  • Helps manage soil mositure
    Biochar can absorb many times its own weight in water, reducing the need for watering and creating less stress for your plants. And in heavy clay soils, it improves drainage. 
  • Resilience & root growth
    Trial results have shown higher plant survival rates and substantially increased roots systems. It has been shown to work in all soil types.
  • Resilient, healthier plants
    Creates healthy soils and vigorous growth, and helps plants to become resistant to drought and disease. Recent article on Country File explored the beneficial impact that biochar is having on in trials aimed at preventing young ash saplings from developing the devastating ash dieback.
  • Doesn’t decay
    Biochar is largely inert and will not decay, so it will keep working for thousands of years and so fix the related CO2 for the same period!

Potential ways to use Biochar

  • For 10% biochar in your flower beds or veg plot sprinkle about 3 kg raw biochar over 1 m2 of soil. Then add a compost of your choice and dig it in to about 5 inches deep.
  • A more economic approach may be to only add your biochar to each individual planting row or each planting holes rather than a general top dressing. Dig your planting trench, apply a layer of biochar, cover with your compost. Then do you planting and backfill your trench. 
  • Enhance your pot plants by mixing raw biochar with compost. For a 10% biochar mix add 1 kg to 40 litres of compost. Mix well.
  • You can dress the surface of a patch of soil or plant pot with a 50/50 mix of biochar and compost made up of 1 kg of raw biochar to 4 litres of compost.
  • Sprinkle a thin layer of pure biochar on the surface of a plant pot or soil around ornamental plants.

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