The special charcoal known as biochar is one of the best things you can add to your soil. Baked at a lower temperature than standard charcoal, it has an extremely porous structure – making it the ideal habitat for the beneficial bacteria and fungi that enrich the soil and make it fertile. It can do wonders for your plants and veggies! But how do you use it?
Here are our five tips:
1) Don’t use raw biochar
The ‘raw’ biochar straight from the kiln is not the best thing to put on your soil, as it has not had any ‘life’ added to it and so doesn’t contain any nutrients. When added to the soil, biochar in this state can actually diminish crop yields over the short-term, because it reduces the availability of plant nutrients by binding and immobilising them for a period of time. In the long-term it will, ultimately, improve the soil and establish a healthy population of the microbes essential to its health. But if you don’t want to wait several years, then you need to prepare biochar before putting it on your soil – by activating it.
2) Activate your biochar
This means ‘inoculating’ your biochar with nutrients before adding it to soil. There are several ways to do this. You can put it in your compost heap for several months. Alternatively, if you keep chickens, you can put some on the floor of your chicken coop for a good few months, where it will soak up chicken urine and faeces (also taking away the smell too!).
However, both these methods take time. We believe the best and quickest way is to mix the biochar with a series of potent, soil-boosting ingredients.
These can include worm casts and seaweed (ensuring the latter is storm-cast, which means it’s been stranded on a beach. Please don’t pull seaweed off rocks, this is the equivalent of uprooting plants.) Biodynamic preparations are another fantastic way to charge your biochar with nutrients. You can buy them from the Biodynamic Association (also, they need to be added in a very specific way, so please seek advice from the BDA about this too). Finally, we’d recommend steeping your biochar in comfrey tea, for anything from a couple of days to a week.
3) Make a mix
Biochar is not soil, so you shouldn’t try and grow anything in pure biochar, even after it’s been activated. When it’s time to add it to your garden, allotment, raised bed or tub, you need to mix it with your usual soil and/or compost. The ratio should be about 5 to 10% biochar to soil or soil/compost mix.
4) Add it in the autumn
Most gardeners think spring is the time to prepare the soil for the growing season. However, with biochar, the best time to add it to the soil is autumn-winter.
After the growing season, soil is tired and depleted. Much of its goodness will have been extracted by the plants and crops that’ve been growing in it. It rests during the autumn and winter, making it exactly the time when you should be adding activated biochar. You need to replenish its microbial ecosystem – ensuring it contains lots of the beneficial bacteria and fungi that provide nutrients for plants during the next growing season. This can take some time, months rather than weeks, which is why the application of biochar should be sooner rather than later.
5) Buy pre-activated biochar
If you would rather simply buy some activated biochar, rather than activating it yourself, then we sell some of the best! Hand-crafted on Sussex woodlands, our biochar is made by hand, using the leftover bits of wood from eco-friendly tree care (coppicing and pollarding). It’s then mixed with worm casts, seaweed, comfrey tea biodynamic compost preparations. All profits from its sales go back into our community project, which provides ecotherapy and nature education to children, teens and adults. You can buy Sacred Earth’s Biochar Soil Booster here.
