If there’s one thing you should add to your soil this winter, it’s biochar. A special kind of carbon-rich charcoal, it offers gardeners and growers so many benefits:
Improvement of soil fertility
Soil is a living ecosystem. It should be teaming with microbial life. There are lots of beneficial bacteria and fungi that are essential to its health. They play a central role in the nutrient cycle that is fundamentally important to all life on Earth.
The presence of biochar helps these microbes flourish. This is down to its uniquely complex and porous structure, which provides their ideal habitat. They thrive in the multitude of infinitesimal nooks and crannies that cover its surface.
Increase in crop yields
Here again, biochar’s spongy, porous structure comes into play. It attracts nutrients and then stores them, meaning they are available to plants when they need them. This is one reason why soil containing biochar is more nutrient-rich. It has lower rates of nutrient depletion during the growing season. At harvest time, this results in higher plant density and crop yields.
Better water retention and drainage
Biochar’s porous structure means it retains water and, so, improves soil’s ability to hold moisture. As a result, it can keep beneficial soil bacteria and fungi alive during a long, hot summer. It also helps with drainage. Its porosity means it acts like millions of tiny sponges in the soil, holding onto any excess water. The soil can later benefit from this stored water when it has dried out.
Reduction of soil acidity
Soil acidity is a major concern. It is difficult to grow most crops or plants in soil with a pH value of 5.5 or less, because nutrients leach quickly from such soils. The ideal pH value is between 5.5 and 7. That’s the range in which the bacteria that change and release nitrogen from organic matter (and fertilisers) best operate.
PH can also affect the structure of the soil, especially in clay soils. In the optimum pH range, clay soils are granular and easy to work with. But if the soil is either extremely acid or alkaline clay, it tends to become sticky and hard to cultivate.
Adsorption of soil pollutants
Biochar can also potentially repair soils that have been contaminated with toxic heavy metals. Its incredibly large surface area and spongy nature means it can ‘adsorb’ or hold onto metals and other pollutants. Its alkalinity is also a factor here. Plant-toxic metals, like aluminium, can be dissolved in acidic soils with pH levels below 5.0. Biochar’s tendency to de-acidify soils also contributes to their decontamination.
Increase in plant disease resistance
There is growing evidence to suggest that biochar has a role to play in improving plant resistance to some pathogens. Scientists are still trying to work out how this happens, but it seems it’s connected to the boosted microbial activity in the rhizosphere, which is the soil directly around plant roots.
Catching and storing carbon
Biochar captures carbon and fixes it in the soil. It is also highly stable and will stay in your soil for the long-term – which means you only need to add it once. The ancient people of the Amazon basin were the first people to add charcoal to soil and the ‘terra preta’ or ‘black soils’ they bio-engineered thousands of years ago remains stable and carbon rich to this day.
This is why biochar has been hailed by environmentalists – from Al Gore to James Lovelock of the Gaia Hypothesis – as a way to sequester carbon in the ground and help reduce our runaway carbon emissions, one of the key drivers of global warming.
These are just some of biochar’s benefits. No other soil amendment will improve your soil to such an extent for the long-term. Winter is the best time to dig it into your garden or allotment, to allow the microbes to start rejuvenating ahead of the growing season. At Sacred Earth, we make our own biochar using the leftover wood offcuts arising from our eco-friendly management of our Sussex woodlands. Try some today by buying it here.