Industrial uses for Biochar

In this article, we look at the uses of biochar as a replacement for Activated Carbon derived from fossil fuels and other non-sustainable materials.

(Biochar for soil, gardening farming, agriculture etc are in other blogs – see the end of the article for links).

Biochar is a sustainable, non-fossil fuel form of carbon.  Wood-based biochar (i.e. charcoal) has been made and used for many applications over millennia. As wood became scarce, and industry need more charcoal, we found new ways to make carbon and activated carbon from oil, methane gas and fossil fuel. Now we are going back to apply modern-day pyrolysis technology to make biochars from sustainable resources that have no negative impact on the environment (i.e. no polluting gasses and minimal CO2 releases).  As we do this, we are also rediscovering many old and some new ways to use the material. These properties of carbon lead to many potential uses of biochars.

We provide biochar for sale from our online store.

Biochar carbon for air filtration

Filtering odours from air and gas streams is one of the core uses of the many types of activated carbons (PAC, GAC etc) manufactured from oil, coal and methane gas. Biochar made from sustainable resources (e.g. wood) can replace some of these. But it is noteworthy that the Activated carbon industry has spent many years working on specific carbons to do specific tasks. Many Biochars are not direct replacements – it will be a case of understanding why each application requires and then matching this to the specific biochar available.

Carbon is used in air filtration (e.g. HVAC, gas vapour streams, scrubbing gas in coal-fired power stations).

The functionality of carbon in terms of adsorption depends on the surface chemistry and surface area. There are numerous carbon ‘activation’ techniques (steam, acids, nitrogen etc) used to alter the carbon for specific applications. Biochar should be tested and efforts made to fully understand the properties of the old carbon and the potential biochar replacement.

Each raw material used to make biochar or activated carbon contains different levels of trace elements that are often carried forward from the organic material into the charcoal and or biochar. For example, wood contains silica, calcium, iron and a host of other trace metals the tree needed to make vital enzymes.  The final biochar (or activated carbon) can contain silica and calcium oxide. In most cases, these trace mineral items will not harm or interfere with carbon use – but this might not be the case. When the charcoal (activated carbon or biochar) is completely combusted (burnt in air), these trace elements convert to non-hazardous oxides and result in a grey/white ash – think of the white powder left after the BBQ burns out!

Biochar for building insulation

Biochar is both porous (holds air) and is a good heat insulator. Some researchers are looking at using biochar in buildings and roads. Personally, the author does not believe the cost/benefit analysis will support using carbon over current materials – but it is an exciting area.

Biochar for odour reduction

Per deodourisation mentioned earlier.

Biochar as a black pigment

The black ink used in photocopiers is a form of carbon black. The largest use of carbon black is in tyre manufacture.

In our opinion, it is unlikely biochar will be used as carbon black. The pigment is incredibly fine particles created during ‘gas phase’ reactions from oil. Biochar is made from ‘solids and comes out as granules/pieces.  These bits would require considerable (and most likely uneconomic and dangerous (explosive) crushing to make a very fine micronized powder.

Other possible uses

– Super conductance/battery / storage devices
– Protection against electromagnetic radiation
– Fabric additive for functional underwear
– Thermal insulation for functional clothing
– Biochar in ore and metal processing as a reduction agent
– Carbon is used in some cosmetic soaps and skin treatments
– Biochar to replace carbon black in some industrial paints

Thank you for reading our blog on the industrial use of biochar. This is one of five articles on the uses of biochar – follow the links below:

Biochar for gardeners – some surprising uses (link)

Biochar for water and gas filtration (link)

Biochar for farming and agriculture (link)

Biochar as a soil improver (main article) (link)

We are working with A Healthier Earth and the Blenheim Estate to increase tree survival and growth rates as they plant 500,000 trees on their estate. Alongside their commitments to the woodland environment, maintaining biodiversity, and using native broadleaf species, this project also focuses on mitigating climate change through carbon locked into the tree growth. A relatively small percentage increase in tree survival rate and annual growth rate will have a huge impact over a 30-50-year period.

Last year was a tough time for newly planted trees. Usually, woodland and forestry tree planting expects around 30-40% sapling loss in the first couple of years, but in 2023 losses on some projects were as high as 70%.  Drought-tolerant trees were high on the project team’s agenda.

Biochar For Tree Planting

Biochar increases water retention and reduces drought stress –  a positive place to start.

Biochar also:

• Improves nutrient supply to roots
• Reduces nutrient losses due to ‘run-off’
• Supports microbes and AMF (mycorrhizal fungi)
• Supports the formation and stability of colloidal humus
• Improves soil aggregation (i.e. tilth)

Our core task was to bring together our existing knowledge of “biochar for trees” and build a ‘best practice tree planting method that would work for hundreds of thousands of trees.

We have a knowledge bank to call on having helped several tree clients with Miyawaki urban woodlands, specimen Tree recovery at Oxford University, Air spade root decompaction, general woodland planting, and of course, supply of Stockholm-type structural tree mixes with additional biochar. (see reference links at end of blog).

Even so, when looking at large new projects it is good to take a step back and look at the science and update on the latest best practice for tree planting. This project has additional complexity around seeking grant funding and approval for carbon offsetting credits. We must look at soil disturbance, mitigating future climate change, and a host of other issues. We undertook a review of the top specialist tree-websites, and Forestry Research guidelines (add hyper).  For good measure. we asked ‘AI’ (ChatGPT) to help!

Tree Planting Best Practice (click title for full article)

This best practice is wonderful – if you are planting a few specimen trees in a garden. However, it is a mile away from the logistical and commercial realities of large-scale forestry and agroforestry plantations. A more typical mass planting method is: to spade-split the soil, drop in a bare root sapling (30-60cm), heel down, stake, and add a plastic tree guard. Rarely if ever does large-scale tree planting receive ongoing watering. We noted some websites reporting professional planters planting as many as 2,000 saplings per person per day – an incredible 4 saplings per minute! The typical planted cost is £2-£3/tree.

When we sought advice about the causes of the high rate of tree losses, we and others jumped immediately to ‘what do expect if you do not water and provide tree aftercare?’.  But this is too simplistic – it is not ‘bad practice’; it is the reality that the cost of piping water and labour to irrigate would be huge. Even if it was affordable, often there is little or no chance of being granted a water abstraction licence from a river/ground source.

Our first ‘best of best’ planting method was as follows: run a backhoe digger up and down the site to remove a 1m channel of soil. Mix the extracted soil 50/50 with biochar tree mix. Add drainage and watering, drop in cell-grown trees, and backfill. Mulch over top the whole 1m wide channel. Stake and protect with new compostable guards. This method was quickly dismissed. An increase in cost from £2/tree (£1m project cost) to £10/tree (£50m project) was not credible to present to the client.

Planting Method – Re-think

We undertook a significant species analysis looking at the local soil, trees already growing at the site, and mixing things up to provide more biodiversity security. With access to very experienced carbon forestry experts, we could also look to the future in terms of climate impacts. One thing we did spot is the UK tree nurseries have invested a lot of time looking at drought-tolerant species in readiness for dryer, hotter Summers. We did not find a lot of discussion around the fact that most large-scale planting will be in poor, clayey soils.  The UK is also going to have significantly wetter and soggy clayey soils in Winter. Species like Alder (Italian) came high up for both drought and soggy!

Armed with 5 species, and a 5X5 randomized test plot of the first test of 1,000 trees, it was time to crack on with the decide the best economic planting.

We have ditched the t-split planting of bare root saplings in favour of using cell/pot trees of 30-60cm in height. (More on this will come later when we outline the full “carbon forest factory” model.   We have automated the hole digging to use a 150mm tractor-mounted auger drill to a 30cm depth, then backfill with the SoilFixer Biochar-Woody Compost tree mix (aka SF40).

Why This Mix?

Knowing the major cause of young tree loss is lack of water, adding more water retention is good. But too much water retention can also lead to all the void spaces in the soil filling with water or swelled clays/gels. This is equally bad news as the roots cannot breathe (respire) and they quickly die back and rot. Dense soils restrict fast root development. Low-density growing substrates like peat, coir, and compost have no weight to hold the roots and hence trees suffer from rocking and poor root development. The mixture is a balance seeking strong growth in years 1 and 2 and then allowing development of the roots into the surrounding soil.  When planting into pastureland, we will dip-inoculate the cell tree roots with AMF powder/solution. Where the planting is back into recent forestry soil we will skip the AMF.

Sidestep – AMF Fungi

AMF are the symbiotic fungi that link roots to plant nutrients in the wider soil structure

We are still searching for compelling evidence that confirms that pasture (grass, crop) soil microbiology and AMF differ from those in a forest ecosystem. As far as we can find, all the commercial AMF powders are all based on 12 major AMF species and there is no specific plant or tree mix. Based on our composting knowledge there is also a strong hint that the white fungi filaments often mentioned as being present in forest litter (and by implication not in crop soils) are in fact ‘lignin (wood!) decomposing fungi’ filaments. Academic papers indicate the decomposing fungi are obligate (ie decomposer only) and do not participate in the symbiotic relationship – ie they are not AMF! The leaf litter (surface) layer is not the root rhizome layer.

Soil Type:

There are online resources that map UK-wide general soil profiles for example the Landis database.  Even within a few miles of our site, there are at least 4 distinct soil types. It is always worth doing local soil tests just to check. pH testing is straightforward and a good pH meter will last years and cost around £30. The first planting site is pH 7.45. Although very rocky, it is otherwise a ‘heavy clayey’ soil. The biochar-compost tree mix we are using is pH 7.0.

Tree Guards

The site has problems with voles, rabbits, and deer. They can wipe out the young saplings within weeks. We have to use tree guards, and for voles, we need to ensure the guard goes into the surrounding soil so they cannot get under.

Going forward environmental concerns may bring in compostable guards. But the sheer scale of planting means that at present the old plastic tree guards are being used multiple times. Eventually, they will be collected and hopefully be reprocessed into biochar!

Growth Rate Testing

We have set up some reasonably sophisticated ongoing tests to look at health and growth over 4 years. We will be monitoring leaf chlorophyll, stem diameter, and removing some saplings to analyse root growth.

We will be announcing the client name in due course when PR departments have approved the content. Do come back for updates.

If you are looking for advice on large-scale, carbon credit forestry with a higher payback please email: help@soilfixer.co.uk. 

Other Tree, Woodland, and Forestry Blogs and Reference Materials

Biochar in woodlands – blog

Our Best Practice Tree Planting Guidelines (for specimen trees) is now published

Stockholm Structured Soil for Urban Planting with Biochar

Our blog on the Miyawaki urban woodland method is here

The Forestry Research Guide is here.

The Forest Research tree specimen database is here

UK-wide soil profiles Landis database

Photo credit: Laurie Campbell / WTML

It’s always a great time to start using the HOTBIN Mega compost bin on your allotment

Why Use the HOTBIN Mega Compost bin?

• Compost within 90 days, all year round

• Excellent quality compost

• Option to make Biochar Super Compost

• Space saving – replace 3-4 pallet frames,  12-16 ‘daleks’, more space for growing

• Kills weed seeds

• No turning

• Year round performance

What’s special about allotment composting?

• Large volumes of green waste (i.e. plant material)

• Often large pieces of plant material and not easy to shred or chop

• Lots of the same item at one time – e.g. clearing out potato crop, end of tomato season, end of cabbages

• Longer season – stretching through winter (e.g. brassicas)

• Existing composting tends to be incomplete and takes a long time

• Often lots of weeds – normal ‘cold’ composting won’t kill weed seeds

How do I use the HOTBIN Mega?

It’s straightforward

• Put the bin together as per the instructions. (Remember to take the charcoal out of the bag and add it loose into the tray in the lid)

• Gather your waste vegetables, weeds etc. Preferably shred and chop it up

• Load the waste in, put the lid on and wait for the temperature to rise!

• If you are making biochar super compost – sprinkle the composting agent onto the compost waste each time you add more waste

• Note: On first use, you need to get the bin 1/3 full before it will kick into the hot zone

• Thereafter you need to add 20Kg (a full wheelbarrow) each week to maintain the hot zone.

• On first use, sprinkle in some old compost on new waste to add microbes and ensure a fast start

• Keep going until full

Emptying out

Take off the ratchet straps.  Lift up one of the wall panels away from the base. You need to lift before you attempt to push out the panel as the wall panel ‘interlocks’ with the base.  See our blog

Do I need to chop or shred?

Yes preferably chop. Composting is always faster to get going if you shred and chop waste. There is more surface area for microbes to attack and you are giving them easy access. The outer peel and stems are designed to protect against microbes – the chopped surface has no protection. (Think of this as infection in open wounds vs unbroken skin).

With allotments, if there is no shared shredder, chopping is often just too time-consuming.  If you don’t chop, then gently push down the waste so pieces are sitting next to each other. Also, factor into your expectations: you add a solid Brussels sprout stem – it is going to take longer to compost (even at 60C) than a chopped-up stem.

What about Green and Brown ratios?

With most allotment waste, the waste will have near-perfect ratios and there is no need to worry or check.

If you are adding high carbon items like wood chip, straw and sawdust they will need balancing with high nitrogen waste like grass, weeds or chicken poo and vice versa.

What if I don’t have enough waste each week?

Don’t over worry if you do not have enough to keep it running at 60C. When you add waste, it will quickly heat up again. You may find it useful to look at our hints and tips and “routines”.  You will quickly establish which option works for you.

Comparing my Mega bin compost to my old compost

If this is the first time using a HOTBIN, it will be worth holding onto a sample of your old compost and taking some notes so you can compare it to the HOTBIN compost.

When you empty the HOTBIN, might we suggest you have a look back at the information on your old compost? If you have a sample, take a handful, dampen it and roll it into a ball in your hand. Do the same with new compost. Now leave both in sun to dry. If you have a nice full day at the allotment, come back every 3 hours and prod them. One will dry out faster than the other into a brown friable pile. You can find out more about types of compost colloidal humus here.

It doesn’t look big enough

The 450 and 700 litre bins look about the same size as a pallet frame bin compost bin. But that’s where things end – do not be put off if you have 3,4, or 6 pallet frame bins. The Mega bin hot composts at 40-60C and will churn through waste 4-32 times faster than a bin in ambient air (the exact speed depends on what you add).

My big compost piles get hot so why use a HOTBIN Mega?

A large pallet frame when full will get hot, but it is likely to only stay hot for few days and the outer layer will not get hot. You will need to turn the outer material several times to get it all composted. Why not have a no turn system and spend all the extra hours growing lovely vegetables.

I’m doing No-dig allotment – do I need a HOTBIN Mega?

No dig requires compost. Usually it is recommended to add this as a top covering.

There is a widely held belief that earth worms and insects will pull compost down into the soil and eat it. There are videos showing worms pulling down leaves.  To a small degree yes, earthworms will eat leaves, but they have no large mouths or teeth; they feed on the soft mushy outer edges that the microbes have already started to digest. The bits pulled down still need to be decomposed by microbes and fungi. If your soil is in good condition and has lots of worms, they will take down small bits of well matured compost faster than rough mulching compost.

Most of the root activity is under the surface around 5-10cm in the so called Rhizosphere. If you are NO-DIG, here’s what we recommend:

Spread the compost as normal in a 5-10cm layer. Water it in using a hose pipe and copious amounts of water (subject to hose pipe bans etc). Don’t be afraid to really pour it on – your goal is to wash all the really beneficial small particles of humus of the larger bits and down into the soil.

A lot of compost comes out of cold heaps only partially degraded. Large bits of compost on the surface dry out.  With hot composting (and especially hot composting with the biochar composting agent), you get far more complete breakdown. In our recent tests of ‘flushing’ we found only 10% of the original compost was left on the surface – this is against 50-60% of the usual compost we purchased (after washing, it was clear just how much wood chip was in the compost!)

I’m doing lasagne layered (sheet composting) over winter – should I move to the Mega?

Like all gardening there are pros and cons of each method.

From our perspective here are some of the cons:

• This is a form of ‘cold’ composting. By this we mean is the compost pile temperature follows the ambient air/soil temperature so in the UK5-15C which means the composting process is slow.

• You lose a large area of ground while the process takes place.

• In winter, when the temperature of soil falls below 5C, the microbes stop working.

• Weed seeds are rarely killed in cold composting.

• There is no science behind layering, it is a compost myth. Microbes cannot jump between layers. If they need more nitrogen (from the greens) it is inaccessible in the layer above (browns, high carbon). There are thousands of large scale compost sites all over the world composting millions of tonnes of plant waste (the UK process about 15 million tonnes into 5 million tonnes of compost a year). We do not know a single site that uses layering – they all shred and mix.

Peat-free biochar multi-purpose compost – why are we making it?

Most garden centres now stock peat-free multi-purpose compost.  (More accurately they stock peat-free soilless growing media tailored for plant growth. Few of them actually contain “compost” – ie the end result from a managed process to break down organic matter into a useful soil amendment. If you need more help with the different types and names of compost have a look at this post.

Many of our readers will know that SoilFixer pioneered adding biochar into the active composting process. Our SF60 Soil Improver is a fantastic soil improver and helps gardeners towards the goal of the famed Amazonian Dark Earth soil composition and fertility. However, SF60 on its own is not a good growing media – we would not sell it as a multi-purpose compost for use solely in containers.

At the start of 2020, we set out to tweak our production to produce and test a biochar peat-free multi-purpose compost that:

• works as a growing media  as well as a soil improver
• is re-usable year after year
• is 100% peat-free, 100% coir free and 100% made in the UK
• offers value for money in terms of the overall benefits

Results Summary SF40 versus leading brands

It would be great to make a growing media that gave substantially bigger and better plants than the leading MPC brand. In reality, this was unlikely. The leading brands have spent 15 years perfecting what goes in them. They mix multiple materials (coir, wood fibre, wood chip, peat), specify different particle sizes, water retention chemicals, water surfactants (re-wetting agents), and slow-release fertiliser prills – everything your plants need to give you the results you want – great container plants.

SF40 has matched and in some cases bettered leading brands. However, biochar brings something new to the party. It can be made in the UK from UK waste wood materials. Biochar locks (sequesters) carbon for hundreds of years. It will survive from 100 to 1000 years in soil and containers. There is a realistic prospect of ‘topping up” and reusing SF40 every year for many years.

Even if you are unlucky and the container plants get infected with disease, correctly composted (eg in the hot system for minimum 90 days) the pathogens can be eliminated and the SF40/compost re-used.

More Detail on the testing of SF40 versus other Multi-Purpose Composts (MPC)

We make our compost and biochar here in the UK. This gives us the flexibility to alter the ratio of biochar and the particle size.  Working closely with our biochar production partner has given us the capability to make biochar more cost-effectively. This has opened up the possibility of changing the ratio of biochar and having a cost-competitive biochar multi-purpose compost. We shortlisted two formulations for a head-to-head test.  We code-named the mixes “2:1” and “SF40”.  Even we were surprised!

(Note: we take care to do controlled and comparable tests, but we are always upfront that plant growth tests are very challenging with multiple variables to control. Test results that will stand up to academic rigour can take many years to complete and include thousands of replications. We are always enthusiastic, but also careful not to go over the top in our claims based on one or two results).

SoilFixer tests, 2:1 mix vs SF40 mix, radish, tomatoes and Sunflower

Radish

Germination and first few weeks:- the SF40 germinated far more…. and faster

Short-term: (2-10 weeks, mainly radish tests) – we observed X4 more total plant growth via SF40 over the “2:1” mix

Tomatoes and Sunflowers

We started to see more early growth in height and spread of the sunflowers and tomatoes planted in the SF40 over those in the 2:1 mix. 

Towards the end of summer, we noticed the 2:1 plants were taller (2.4m vs 2.0m). We then noticed a flaw in the planting – the sunflowers in SF40 nearer to the house were shaded for longer each day.  At the end of September, we cut down and weighed the seed heads, stems, leaves and root ball. When all the weights were added together, there was no significant difference. Both formulations performed equally well for sunflowers.

We planted 3 tomato plants in 2:1 mix and 3 in the SF40 – these were mingled in with the sunflowers. The tomatoes did show a significant difference. Again we weighed the fruit, stems/leaves and root ball. The SF40 root balls were 300% more in both length and total weight. The fruit in the SF40 was 50% more – but when we cut down the plants – we noted that much of the ripe fruit allocated to 2:1 plants was probably from the SF40 plants that have spread and tangled. Overall the SF40 plants showed  75% more growth than the 2:1 mix plants.

 

SoilFIxer SF40 versus leading multi-purpose compost results

SF40 Vs Leading brand – radish results

Germination 11/12 plants for SF40, 5/12 plants for the leading brand MPC  – double

Total growth 94g for SF40  versus  59g for a leading brand (that’s x1.6 difference)

Biggest weights, top two radish weights: 17g and 16g for MPC, 16 and 14 g for SF40

(We note the major difference is that fewer plants germinated in the MCP so fewer plants went on to grow to maturity. We would expect an MCP to be suitable for most seed germination, but do accept many leading brands suggest a weaker fertiliser ratio for seed germination over full-on potting up and container growth).

SF40 Vs Leading multi-purpose compost – tomato results

Germination – 2 seeds of each – all germinated

During the first few weeks broadly about the same growth rates. We observed that during hot days (25-30C) the SF40 retains water far better than the MPC. Despite watering all the pots in the early morning and evening with the same level, by the end of the day, we noted a significant dropping and water stress in the MPC compost.

Long-term, tomatoes at 3 months

We are starting to see differences. The tomatoes in the leading compost appear taller and leafier. Those in SF40 are slightly shorter and have greener leaves and do appear to be developing more fruits. (One other tester has also reported similar with tomatoes. We hypothesize that this is due to SF50 having more potassium and the leading brand having more nitrogen. (Virtually all multi-purpose composts used as growing media will have a slow-release fertiliser pellet in (eg Osocote – which are small white/milky pellets – not the annular bright chips – they are perlite!). (We also noted a flaw in the test design. A week  3, we moved the seedlings into full sun. But the MPC plants shaded out the SF40 at all times of day.

What did our bloggers and testers find?

@the_organic_plot, @saralimback, @theworkinggarden, @emilysgreendiary, @allotment102, @cotswoldpotager, @cj.grows

Pat P – RWB Gardening club

Tomato production is waning now and I’ve cut the plants back a lot as [gone] mad in my greenhouse.

A very good crop despite the excessive heat. They certainly fared as well as all the others, if not better but that may also have been due to the tomato varieties. I grew the same in each pot of biochar and all did well.

Sally M (Instagram and writer)

Very pleased with SF40 – tested it against my own compost with one squash plant in each pot. Perhaps not the best year to grow squash in pots given the heat as both pots suffered from water stress despite watering regularly – I used a layer of wool fleece over the compost in both pots to try to retain water which helped. Plant growth was roughly the same in each – similar length of shoots, the colour of leaf etc. Some of the leaves were damaged by scorching. I didn’t get much of a harvest – one squash off each as the flowers appeared during the heat wave and didn’t set fruit. 

Marie T (Instagram)

Sorry for the delay in response. Unfortunately, I have broken my foot so it had been a bit difficult but not to worry hubby has been on it so I will get more info for you.  Thanks again honestly just love the stuff!

Benjamin P (Instagram)

 Our trial of the SF40 began 10th June, using 35 litre containers and Tomato ‘Magic Mountain’ as our subject. We planted one in the SF40 (A) and the other in our preferred peat-free potting compost (B). Throughout the trial, plants were watered, tied into supports and pruned/pinched out, but never fed.

 Initial growth saw A to be smaller and tighter in size, though the foliage was a darker healthier shade of green than B. A also developed fruit trusses a little earlier than B, and there were more of them resulting in A cropping first and for a longer period of time. During the length of the trial (June till October) A produced 103 tomatoes as opposed B which produced 85 (see monthly counts below). Both still have lots of tomatoes still to ripen and so plants will be moved in under glass to avoid the cooler wetter conditions.

 Though this was an isolated trial of just 2 plants, I was encouraged by the results and love how the compost can be ‘reactivated’, rather than replaced with fresh compost. I would be keen to use the product again and very interested to see results from a larger trial.

Tomato harvest

	Jul	Aug	Sept
A (SF40)	3	52	48
B (Melcourt peat-free)	0	43	42

Chris J (Instagram)

I have to say that my tomato growing experience this summer has been slightly disappointing though that has absolutely nothing to do with the SF40.  The tomato plants I have tended and cared for have hardly borne any fruit but the self-seeded plants that got among the blueberries have been bending under the weight of the fruit.

In terms of SF40 compared to the Woodland Horticulture peat free multipurpose the plant has been double the size, a much darker healthier foliage and double the amount of fruit. A mighty 8 tomatoes.

During watering, the SF40 soaks it up like a sponge whereas it pours through the other and then sits in the tray for several days attracting mosquitoes.

Repotting with SF40 was significantly easier too, the root structure much thicker holding the root ball together during transplanting where the other compost would crumble off at the top and be sludgy and probably anaerobic at the bottom

Using a biochar rich compost has reinforced my belief that biochar needs to be part of horticultures future and it will definitely be part of mine.

I’m hoping to be able to get one or more bags for next season to use on its own and to enhance my compost mixes for cacti and houseplants.

Many thanks for allowing me to participate in your trial.

 

(Dr Ian R feedback/report is posted separately).

Summary SF40 to leading brands

It would be great to make a growing media that gave substantially bigger and better plants than the leading MPC brand. In reality, this was unlikely. The leading brands have spent 15 years perfecting their MPC blends. The science that goes into some of them is amazing – they mix multiple materials (coir, wood fibre, wood chip, peat), specify different particle sizes, water retention chemicals, water surfactants (re-wetting agents), and slow-release fertiliser prills – everything your plants need to give you the results you want – great container plants.

Biochar brings something new to the party. It can be made in the UK from UK waste wood materials. Biochar locks (sequesters) carbon for hundreds of years. It will survive from 100 to 1000 years in soil and containers. There is a realistic prospect of ‘topping up” and reusing SF40 every year for many years.

Even if you are unlucky and the container plants get infected with disease, correctly composted (eg in the hot system for minimum 90 days) the pathogens can be eliminated and the SF40/compost re-used.

Our goal is to produce comparable plant growth per the leading peat-free brands. We are currently doing internal testing against what we regard as the leading UK multi-purpose compost. We have one tray of radish seeds and one container of tomatoes.