How To Make Charcoal & Biochar For Your Garden

Barbecue veggies

One of the joys of summer in the garden is being able to eat outdoors. Barbecues are a fun feature of the summer and can be a great way to make the most of your garden while the weather is sunny and warm. Those who are interested in gardening sustainably and making the most of the resources that their garden can provide can make their own charcoal for summer barbecues using pruned branches and other wood from their outside space.


There are, however, more ways to use charcoal made with garden wood. Charcoal can be infused with compost tea in order to create a high-fertility soil amendment – biochar – which can be wonderful for enhancing the topsoil in sandy or degraded gardens. Biochar can be a valuable addition to growing areas and using it will not only help the plants that you wish to grow, it is also a good way to store carbon – which can help to combat greenhouse gases and global warming.

Making your own charcoal and biochar is easier than you might imagine. Charcoal is made basically by burning wood in the absence of oxygen. By excluding (or at least reducing) the oxygen that can reach a wood fire, you can create charcoal to use on barbecues in your garden, or to make biochar to amend the topsoil in your growing areas.


If you plan to make biochar, the easiest way to do so is in the ground. Native peoples in the Americas used this technique to create more fertile growing areas. After you have harvested summer crops from a growing area, dig a pit and fill this with wood. Then simply set this alight and cover it with a blanket of soil to exclude oxygen. Once the area has stopped smouldering, simply water the area with a nutrient rich compost tea, which will be absorbed by the porous charcoal.

To obtain charcoal without digging up your growing area, you could consider using primitive techniques and garden resources to create a charcoal 'oven'. Make a tipi-like stack of wood and cover it with mud/clay, leaving a hole open at the top. Make temporary ventilation holes around the base. Light a fire at the top and allow the fire to spread down through the structure. When you see flames through the holes at the base, block all the holes to exclude oxygen. Leave overnight. The next day, create a door in the oven and break it open to retrieve what remains inside. There will be some partially combusted wood and ash, but should also be plenty of charcoal. You can then reuse this mud/clay structure to make more if you wish.


Of course there are better, more refined ways to make charcoal using metal containers etc... but the benefit of the techniques above is that anyone can do this in their garden, using materials that they are likely to have to hand. Learning old techniques like these can be another great way to enhance your resilience and make the most of your garden in the most sustainable way possible.