Biochar - Uses Around the Home
This blog looks at possible uses of biochar around the home. The headline topics are:
- Biochar versus BBQ charcoal
- Biochar to clarify the water in flower vases
- Biochar in indoor plant pots
- Biochar to control odours
- Biochar for composting toilets
- Biochar for human consumption
Just a comment around the rapidly growing list of biochar uses. There is a risk that biochar becomes hijacked and positioned as some kind of 'miracle compound' and 'silver bullet solution'. This really is not the case. Charcoal (carbon) has been used for many applications over millennia. As wood became scarce, charcoal was replaced by activated carbon made from oil and fossil fuel. Now we are going back to learn how we make biochars from sustainable resources. As we do this, we are also rediscovering many old and some new way to use the material. But carbon (charcoal and all biochars) have always had fascinating chemical and physical properties leading to many beneficial uses.
Biochar as a replacement for BBQ lump charcoal
Charcoal making is an ancient art that goes back thousands of years. It is still practised in the UK by coppice workers to make hardwood (lump) BBQ charcoal, (see national federation charcoal makers) and all over the developing world to make a cooking fuel (good review at UN-FOA). Although charcoal and biochar share similar manufacturing techniques (pyrolysis) and the same chemical properties; there are subtle differences between the two. To qualify as Biochar under one of the quality standards (International IBI, European EBC), the production technique should use sustainable organic resources in a non-polluting system that preferably re-uses the pyrolysis heat. Much as we admire the art and skill of making charcoal in traditional earth and ring kilns, most of these kilns produce substantial amounts of harmful pollution gases and the heat is usually wasted. The production of lump BBQ charcoal via ring kilns fuel always results in ‘fines’ (small pieces, typically less than 15mm) that are unsuitable for BBQ use. These ‘fines’ can be used as horticultural charcoal (ie a form of biochar).
For the sake of completeness, we should note that Biochar derived from wood from an approved biochar technology COULD be used for BBQ fuel – HOWEVER – it fails to meet the core mission and rationale for making biochar, ie, burning it will not improve soil nor see it permanently sequestered (locked) into the soil.
Biochar added to cut flowers in vases
Pop a few lumps of biochar in the water in your flower vases. It will remove discolouration and help keep the flowers fresh for longer. (We know biochar cleans (clarifies) the water – on day two the water was cloudy, added biochar day three clear. The water stayed clear to the end (14 days). We do not have extensive tests for how much longer the flowers last. In our simple test, the cut Sunflowers lasted 14 days and the stems had no visible decay at the end. If you are in the flower trade would like to do extensive tests of how biochar can help extend the shelf life of cut flowers please - contact us.
Biochar used as a base layer for indoor potted plants
Put a layer in the base of your indoor plant pots. Not only does this act as drainage, it will also help transfer oxygen to the roots.
Biochar as a base layer in pot trays
See the header photo – this final layer will mop up nutrients that might otherwise leach out on watering. It also allows more air into the base.
(For more information on using biochar as an indoor potting mix and plant growth media visit the first part of the series. This article also covers specialist topics such as Orchids (phals), Bonsai, aquaponics, and hydroponics)
Biochar used as a top layer cover around potted house plants
We have found sprinkling biochar around the top of potted plants to be beneficial. It stops the soil/compost mix from compressing. Sure I’m not alone that when watering the house plants I use a watering can, milk bottle or mixing jug without any sprinkle-rose attached. The water gushes on to the soil/compost which then becomes compressed and harder to water. Biochar chip is physically strong and helps slow down the water – it keeps the soil below in good condition and helps reduce water loss from the soil. Using biochar outdoors as a mulching layer is not cost-effective, but on treasured in-door plants, well worth the extra effort.
Biochar as a slug barrier
We have not proven this yet, but we expect the rough edges of the char to act as a slug barrier. So in line with other slug barrier treatments, (many costing £8-£20 per packet!) adding a circle of chips around a plant could help prevent slug attack. If it does – the next thing is it will be helping the plant growth at the same time as protecting the plants. If anyone has any undertaken in-depth testing let us know! If you have the set up to test it as a slug defence, please contact us. We can easily supply samples in exchange for using the results in our publicity!
Biochar use in composting toilets as a bulking agent and odour treatment
We are very interested in the growth of composting toilets – especially at events like Glastonbury and other music festivals. We are keen to catch up with compost toilet suppliers.
Normally sawdust is used to cover the faeces and reduce evaporative odour. Biochar can do so much more - it will cover the waste and it will also actively remove odour and support aeration so the bacteria can breakdown the material into high-grade compost.
Biochar as a foot odour eater
Using activated charcoal as the active ingredient in foot odour eaters is a well-trodden path (ouch!). Carbon is added to many of the black coloured 'odour eater’ foot insoles. The issue is how to add biochar powder without combining it into a foam matrix. Adding the black powder into the shoe will give you black feet and socks – ant it is VERY hard to remove carbon or biochar powder from the skin – it requires lots of washing up liquid or soap – we know because we have to clean the char from our hands!
One option is to use a small 1 litre bag of carbon granules in the bottom of the shoe cupboard to help remove residual foot odour.
Biochar as a kitchen odour remover
Have you ever wondered how to get rid of that fish smell after grilling a nice bit of salmon or other fish in the kitchen? Even if you use the cooker hood – it just seems to be around for days after. Try this – after you have turned off the noisy cooker hood, put out a bag of biochar chips (in a net filter bag, or old nylon stocking out on the unit top or kitchen floor. Biochar, like activated carbon, is a great odour eater. Now when we tested it we did happen to have a large bucket (30 litres) which we left out and all odour was gone by morning. A smaller amount will be less effective, but on the upside the cost of activated carbon filters for kitchens are huge – so they represent a bargain
Biochar as a fridge odour eater
You can place a filter bag of charcoal in the fridge. As charcoal can always drop a bit of powder onto surfaces, we normally say put the bag onto a plate or dish. After 3-6 months, the biochar will be full (spent, used up). Simply add the used filter to your compost. We only sell the odour filter bags via ebay (add location)
Biochar as a drawing media
Charcoal is one (if not) the oldest drawing materials known. Today, artists tend to look for very regular pencil-type charcoal sticks. It is entirely possible to make these in a biochar kiln – we have seen them. However, this is a low volume use.
Biochar as a food colouring and food supplement
In Europe, we have an approved food additive known as vegetable carbon (carbon black) ie E153. Early indications are that quality biochar powder will meet the standard for E153. Please note we do not advocate using any form of biochar or charcoal without first assessing and checking it is fit for purpose.
Biochar as a poison adsorption agent
Charcoal (of the correct quality/grade) formulated into small dosage capsules when used under the direction of a qualified doctor (or vet) is an established emergency technique to combat certain ingested poisons in humans (and other animals).
Thank you for reading about possible uses of biochar around the home. This is one of five articles on the uses of biochar - follow the links below: