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Tag: food waste recycling

What is hot composting?

Posted on by Julie Halford

Hot composting is a way of composting that uses various techniques to achieve higher temperatures than the traditional method of composting. As a result, you can add a wider variety of food waste and compost will be produced faster.    

A compost bin isn’t absolutely necessary for hot composting – you can hot compost in a large pile – but using a container makes the process more manageable and less messy.

Hot composters are designed to nurture heat-generating micro-organisms and to retain the heat they create as they break down organic waste and multiply.

For hot composting, you need the right ingredients in the correct proportions mixed properly.

What are the advantages?

Hot composting takes more effort than traditional composting but most people find it’s worth it for the benefits, such as:

  • A wider range of foods can be composted that are not usually recommended for composting, such as cooked food and meat.
  • Pests are deterred because food scraps break down faster at higher temperatures.   
  • Pieces of natural clothing, such as wool, cotton and linen, can also be added. These usually take a long time to break down in traditional composting (usually called cold composting).
  • Weeds can be killed at high temperatures.
  • Faster compost is produced in around 4-6 months. Cold composting takes between 6- 18 months.

Materials:

The eco system in a compost bin thrives on a balanced diet of nitrogen and carbon. Nitrogen is needed by the micro-organisms for growth and reproduction, while carbon provides them with energy.  

Nitrogen-rich materials are wetter and faster to break down. Carbon-rich materials are dry and slower to break down. In composting terms nitrogen materials are often referred to as Greens and carbon as Browns.

Nitrogen (Greens)

Food waste

Coffee grounds

Fresh green garden waste, such as grass mowings and green leaves

Wilted flowers

Seaweed/kelp

Tealeaves, tea bags (non-plastic)

Natural fabrics

Manure from herbivore animals

Carbon (Browns)

Dead leaves

Paper

 Cardboard

 Woody garden waste, such as twigs, branches and stalks

Wood chips from untreated wood

Sawdust from untreated wood

Pine needles/ cones

Straw

An image of a very full Green Johanna composter

Balance

Ingredients are added in proportions referred to as the Carbon: Nitrogen ratio (C:N ratio). The ideal C:N ratio is considered to be around 30:1 but it would be difficult to calculate this exactly as every item has a different ratio. Most plant materials are a mixture of both, but more carbon than nitrogen as they get older and tougher.  You don’t have to be too precise with this or worry about it too much.  

A good guide is to simply add equal amounts of carbon to nitrogen (followed by a thin covering layer of carbon to prevent smells), then observe the bin’s contents and make adjustments if your compost lets you know something is wrong.

For example, if your bin starts to smell unpleasant, it’s likely that there’s too much nitrogen and not enough air. If breakdown is very slow, there’s probably too much carbon.

Adding waste

Hot composting can be achieved using different methods; our focus here is on active home composting where householders use one or two bins in an ‘add as you go’ system, adding food waste as it occurs every couple of days, mixed with carbon content.

Aeration

Good airflow is essential for hot composting. The micro-organisms that create heat are aerobic so need oxygen to survive. This is achieved by regularly aerating the bin’s contents, stirring and turning the waste materials with an aerator stick.  

An image of a man mixing composter in a green johanna with the aerator stick

In the immediate aftermath of turning there will be a dip in temperature but ultimately it will result in a higher bin temperature for a longer time.

At the outset, covering the bin’s base with a layer of 15-20cms of twigs will help to create airflow through the contents.

Aerating compost:

  • Helps all materials to make their way to the heat in the middle and to decompose at an even rate. 
  • Prolongs the time that the bin stays at higher temperatures.
  • Helps to distribute water and nutrients to all areas. 

Moisture

Moisture is essential for efficient composting. The contents should be moist but not saturated, with a moisture content of roughly 50 per cent.

The consistency of compost should be damp like a wrung-out sponge.  You can check this by doing a squeeze test – take a few handfuls of compost from different parts of the bin and squeeze – only one or two beads of liquid should be visible.

If compost becomes too wet the water will deplete the amount of oxygen in the bin. Then microbes that thrive in anaerobic conditions will take over, causing slow breakdown and an unpleasant smell. In this case, you should add more carbon content and aerate well.

As micro-organisms become more active, they use up water, causing the compost to dry. In dry compost, microbes will not be active or reproduce.

 If you are regularly adding food waste, there will usually be enough water content in the bin. If you do need to add water, ideally use stored rainwater from a water butt added to a small watering can with a fine rose spray.

Chop or shred

For hot composting, it’s best to chop or shred the materials before adding them. This increases the surface area in contact with microbes in the pile. Smaller pieces – ideally 2 to 5 cm – also make turning the pile much easier.

If you have access to a shredder, you can shred Greens and Browns at the same time, blending materials as you shred. This creates a fine-textured mix that heats up quickly.

Alternatively, you can chop materials using a pair of hedge clippers and a board.

Large pieces will still break down but will take longer. You can get away with larger pieces if you also have other ingredients with a much smaller surface area, such as grass or sawdust.

 If items are too small, they can clump together, reducing the ability of air to circulate through the bin.

What happens?

When there’s enough carbon to fuel these billions of micro-organisms, enough nitrogen and water to help them grow, and enough oxygen to let aerobic bacteria thrive, composting magic happens.  

Heat builds in the bin and heat-loving bacteria multiply, breaking down the materials.

As the temperature increases in the bin, different populations of micro-organisms rise and fall, either going dormant, or becoming fodder for the next wave of bacteria that thrive in even hotter temperatures.

When temperatures are between 20-40 degrees Celsius, this is called the mesophilic phase; from 40-70 degrees Celsius is the thermophilic stage when fast, hot composting takes place.  If temperatures go above 72 degrees Celsius this is too hot for the aerobic micro-organisms to survive. This will cause the process to slow down or stall.

The power of observation

Composting depends on a blend of factors: contents, moisture, size of materials, size of bin, the composter’s efforts, climate and soil conditions.  Even neighbouring households will experience different outcomes due to a difference in diet.  

 Ultimately the best guide is your own observations – how your bin looks and smells. With experience you develop a feel for your materials and can tell what’s needed just by looking.

 Most people find the fact that they can influence the quality and speed of their compost a rewarding aspect of hot composting.  

Why a Green Johanna works well for hot composting

  • The Johanna has been designed so that vents take air in at the bottom to send it upwards through the bin. Incoming air goes up past the four ventilation plates on the inside of the base plate, past the maturing compost layer up into the decomposing compost where it provides oxygen for the micro-organisms.
  • Ventilation in the lid helps control airflow depending on conditions. Switch to minimum in cold weather to keep heat in the bin.
  • Use of the Insulating Jacket helps to control temperature.
  • The conical shape encourages compost to fall back into the centre and not stick to the sides.
  • The generous capacity of 330 litres means the mass of materials acts as an insulating factor.
  • The Green Johanna is recommended as a Best Buy by Gardeners’ World magazine and Which? consumer group.

For more information about composting in general we recommend A Gardener’s Guide to Composting Techniques by master composter Rod Weston.

Green Cone still going strong after 25 years

Posted on by Julie Halford

Although a Green Cone is expected to last for at least 10 years, customers often report their Cone has lasted a lot longer than this.

The oldest Cone that we’ve heard of belongs to a lady in Scotland, who got it through her local authority, Argyll and Bute District Council, 25 years ago.

The customer’s daughter contacted us when the Cone’s lid blew off in a storm and Great Green Systems replaced it free of charge.

 She said: ‘The Cone is still going strong, a real asset in a rural area where there is no specific collection of food waste. ‘

Another Cone going strong, and coping with extreme heat, is one that was taken to Spain by its owner, Angela, nearly 20 years ago when she bought an old Spanish farmhouse.   

Angela knew the Cone worked well at home in England so it would be an even greater asset in Spain, with heat, foxes and rodents to contend with. The family took their Cone over to Spain in their car.

‘We love our Cone and it is really, really useful,’ says Angela.  ‘I must say that we have been surprised and delighted that the actual Cone has lasted brilliantly all these years. We wouldn’t want to be without it.’

For several years the family made annual trips to their Spanish house, spending working holidays getting the house and garden ready for their eventual move.

On one visit a big family birthday was celebrated with 10 guests staying for a full week. The Cone’s underground basket (which is where food waste lands) was full after the week, but when the family returned months later they were delighted to find that the basket’s contents had almost completely vanished.

A long reign in Spain – Angela’s Green Cone outside her Spanish farmhouse.

The family relocated to Spain a few years ago and over the years Angela has seen big changes there in attitudes to recycling food waste.

She says: ‘Things have become easier over the past few years as Spain has started to install special organic recycling bins, which have a swing top and drop waste into an underground receptacle that is then cleared very regularly by the council.  

A good ecological cycle

‘So, from nothing less than 20 years ago, we have multiple ways of safe and hygienic organic waste disposal, the most convenient of which is our Cone.

‘To be honest, it is as much of a pleasure to take the bin out to the Cone as it is to go out and pick veggies for supper because it is useful to process things ourselves and know that we are using a good ecological cycle for production and waste.’ 

The couple grow a lot of their own produce and have had to contend with many challenges posed by the climate and mountainous geography. Their Cone has been moved four times, with placement being determined by where there is sufficient depth to site the basket, which needs to be embedded in soil.

‘When there is torrential rain and it floods over the terrace behind our land it can remove soil down to the bedrock, it was quite a shock the first time we saw this and realised just how little soil covering there is in some places,’ Angela says.

‘As a consequence, we have built raised beds for some of our produce and will be looking to make deeper beds for some others as time goes by.’

A 5000-litre tank for rainwater has been an essential investment.

Angela says the Spanish are becoming much more interested in tending gardens.

 ‘People have been quite interested in our approach (raised beds, adding marigolds for insect control and so on). Possibly they will become more interested in composting as well since many areas have banned burning of waste, partly as a fire hazard and partly air pollution, so things are changing gradually.’

Feel too old to compost? Bokashi’s the answer

Man emptying food into a bokashi bin
Posted on by Julie Halford

My parents and I were discussing the fact that their local council doesn’t yet operate a separate food waste collection.

My mum said it wasn’t a huge deal for them because they didn’t have any food waste anyway.

 I queried this; they must have food waste.  She maintained that they didn’t.

I said I wondered if they ate eggshell sandwiches, or tea bag pie, or perhaps apple core crumble. She said she wondered if I was being sarcastic.

Of course, they didn’t eat those things, she said, but that wasn’t waste ‘because you couldn’t eat it anyway’. It became clear that the word ‘waste’ meant different things to each of us.  

‘Our generation sees waste as something you scrape off your plate,’ Mum said. ‘So it’s the result of not planning properly and cooking too much or putting too much on your plate.’

My parents’ generation of ‘war babies’ equate the word waste with wastefulness.

Wasting food

This might go some way towards explaining the confusion that arose some years ago when research was being done to establish what residents’ attitudes would be if their local council offered voluntary food waste collections. Researchers found that many people said they wouldn’t use a food waste collection because they had no food waste. This didn’t stack up as it didn’t equate to the amount of food waste that the councils had to dispose of. Perhaps these respondents were people of my parents’ generation who thought that if they weren’t ‘wasting’ food they had no food waste.

After our discussion, Mum started thinking about everything she threw in the bin. She realised that she created large amounts of peelings because she makes fresh soup every day.

The next time I visited, she said that because they didn’t yet have any information about when their council would start food waste collections, it had been preying on her mind that every scrap in their bin went to landfill.

But they also felt ‘too old at our age’ (81 and 84) to start stirring compost.

Starting with the belief that you’re never too old to save the earth, I came up with a solution – Team Bokashi. It would work like this:

  • A Maze Bokashi Bin would fit neatly on their worktop, or under the sink, and they could scrape all their food waste into it.
  • By adding Bokashi spray or Bokashi bran to each input of food waste, natural beneficial microbes are introduced which accelerate the fermentation process. (Bokashi is Japanese for ‘fermented organic matter’).
  • Because the waste ferments anaerobically (without air), there are no flies or smells.
  • Once the bin is full, it is left sealed shut for two to three weeks while the contents are left to ferment. Then the contents would normally be added to a garden composter, where it acts as an accelerator, or buried in the garden to break down and become soil-building compost. But I don’t see my dad at 84 being keen to go round digging holes in his garden, so I said I would take the bin and add its contents to our own Green Johanna or Compost Tumbler and hand it back to them. Using two bins on rotation should do the job.

In a way, it’s our own version of what the ShareWaste app does – connecting people who would like to recycle their food scraps with other people who are already composting.

My dad came on board when I explained that the liquid you drain every few days from the tap at the bottom of the bin is a great organic drain cleaner that controls smells and prevents algae build-up.  You can also dilute it for use as plant feed, but it looked like the plants would have to go hungry. My dad has always had a thing about blocked drains. I think it’s a man thing. Using the bokashi drain cleaner might save them a small fortune on whatever gunk he normally chucks down the plughole, and it wouldn’t be a bad thing for the water system too.

I gave them the Bokashi bin and left them to it. Would they become bokashi fans or might it be too much change too soon?

At first Mum argued that there was no space on the kitchen worktop (what with her soup maker, bread maker, food processor etc) for the bokashi bucket so it was given a home on the patio table outside. After a few weeks, however, she did rearrange her worktop space to accommodate the Bokashi bin and the sky didn’t fall in.

No blocked drains

Dad expressed disappointment that he wasn’t getting the promised Bokashi drain cleaner. I explained it was quite normal to go a week at first without liquid while the process got going. Then he forgot to check for a few days and ended up with half a jugful of the stuff. He was highly delighted. I could tell no drains were going to get the chance to get blocked around these parts.

Bokashi ‘tea’ drain cleaner

My parents reported that after a few early instances of forgetting they had a new food waste bin, they quickly got the Bokashi habit. It was now unthinkable for them to throw food waste in the normal kitchen bin, as they had done for the past 80 years.

Bokashi convert

Mum is now a complete Bokashi convert. She says she feels ‘empowered’ by being useful.

‘We all have to do something about the climate crisis,’ she says, ‘and this isn’t a lot to ask, especially when you consider the upsides.’

All that remained was to take a photo using Mum as a model for this blog, showing ‘People in their eighties getting the Bokashi bug’.

But when I turned up to take her photo, Mum had just been out and was looking very elegantly groomed – and not a day over 60.

I was dismayed. ‘You’re going to ruin my photo, you don’t look old.’

‘Really?’ she said, delighted. ‘You’d better use your dad then.’

Julie

Man emptying food into a bokashi bin

Dad does his bit – using a Bokashi bin

How to get the most from your Green Cone

Posted on by Danny Pale

Get the basics right and life with a Cone at home is simple and convenient.

The Green Cone’s basic needs are:

  • A sunny spot
  • Well-draining soil (not clay or chalk)
  • Additions of food waste – no garden or paper waste
  • Accelerator powder to boost digestion

Where shall I put my Green Cone?

When thinking about where to place the Cone, as well as finding a sunny spot it’s a good idea to think about how easy it will be to get to in winter months to empty your kitchen caddy.   

More than 90% of the waste added to the Cone will be turned into water, which must be able to drain freely away for the unit to work properly.

Food waste is digested by micro-organisms in the Cone’s underground basket. Food waste should never come higher than the basket into the Cone itself.

How do I know if I have good drainage?

If you’re not sure whether your soil has good drainage or not, you can check by doing the following: dig the hole required for the Cone (about 70cm wide by 54cm deep) and pour a bucket of water into it. If the water remains for more than 15 minutes you have poor drainage and will need to enlarge the hole to 90cm wide by 70cm deep.

Provide extra drainage by mixing soil from the hole with gravel, stones, or small pieces of broken bricks and pots and placing some of this mix in the base of the hole so that when the assembled Green Cone is added the basket sits 3cm below ground level. Then use the gravel/soil mix to backfill gaps around the Cone until the bottom rim of the green outer cone is fully covered.

How do I look after my Green Cone?

Basic maintenance involves ensuring that the Cone’s green rim always remains below ground level.

In the first few weeks after installation check that soil has not settled and left the green rim exposed. This could also happen after heavy rain. If this is the case, make sure to add additional soil and compact it around the Cone to keep the rim securely underground.

How much waste is too much for the Green Cone?

Remember that food waste should only ever be in the underground basket: never allow waste to build up so that it is above ground level inside the Cone itself.

The Cone is expected to cope with the food waste produced by the average family of four, but this can vary greatly. If you find you regularly have more waste than the Cone can cope with you may need another Cone to cope with all your leftovers.

If you find that in autumn and winter the digestion process has started to slow down and the waste in the basket doesn’t appear to be reducing, simply add a little more accelerator powder.

Why the Green Cone is a bear necessity

The Green Cone was designed by an engineer in Canada to solve the problem of bears pushing over rubbish bins to get to food waste. While bear-proofing may not be on your list of requirements, the Cone is sure to deter local foxes.

If vermin are a problem locally, you can add additional deterrents by hardening the area close to the Cone with bricks or rocks and by positioning the Cone away from fences, woodpiles and bushes.

If pet waste is to be added to the Cone, the unit should not be placed in soil where vegetables are grown or close to any water source. Pet waste should only be added  in small amounts and never in bags.

No bags of any kind should ever be added to the Cone as this will hamper the digestion process.

Why our Green Cone was a very good buy

Posted on by Julie Halford

Before buying their Green Cone in 2009, Jack and Joan Milner, from Leicestershire, thought the prospect of being able to safely dispose of all their leftovers sounded almost too good to be true.

‘We were a bit sceptical at first,’ admits Jack. ‘We had already tried having a compost bin but we were not systematic enough to make it work.’

But at the time Leicestershire County Council was offering residents subsidised Cones to encourage them to recycle food waste at home instead of sending it to landfill. So the couple decided to give it a try.

A place in the sun

Under the scheme at the time, the council arranged for Green Cones to be installed on their residents’ behalf since the units must be dug into a hole in the garden.

 Once this was done, and the Cone was in place in a sunny spot near the kitchen door, the Milners began to feed it their leftovers, including bones.

‘It wasn’t long before the Green Cone was called ‘George’ (don’t ask us why!) and we fed him daily,’ says Jack.

 A pleasant surprise

The couple, now in their eighties, were quickly won over by George’s powers of digestion. ‘We have been very pleasantly surprised.’

Jack and Joan sometimes have to deal with the common problem of visiting dogs and cats leaving a little deposit on their lawn, but ‘George’ has even been efficient at dealing with this.

Most of the waste deposited in the Cone breaks down to become nutritious water that drains from the underground basket into surrounding soil. The Milners have noticed the effect of this soil conditioner on their garden.

A very good buy

Their Cone was placed in an arid spot which sported a few Lily of the Valley flowers and these soon began to flourish, becoming ‘a superb patch two metres in diameter.’

Jack adds that their Cone is now becoming a bit brittle but still ‘completely serviceable’, and it is only now after 13 years that it might need emptying.

‘Overall, George has been a very good buy.’

What’s in a name?

Incidentally, the Milners are not the only customers who have found themselves giving a name to their food waste digester. In our reviews section is a family who named their three Green Johanna Hot Composters Bertha, Belinda and Beryl. Whatever you may wish to call your Cone (and names are not obligatory, we don’t check!) we’re sure life with your own George, or Daisy or Engelburt will be just as good as the Milners’ experience.

And remember, Great Green Systems are here to help if you have any queries or problems.   

Composting in communities? Anthea shows how

Posted on by Julie Halford

When Anthea Rossouw tried to get people into composting years ago, they thought she was crazy.

‘I just got blank stares,’ she recalls. ‘At the time there weren’t studies that proved what composting could do. People just wanted to throw things in the bin. Composting was a controversial idea.’

But Anthea is passionate about the environment and has a way of bringing people with her. Using workshops to show how to use the Green Johanna, she introduced composting to the housing complex in West Sussex where she was living at the time. This was so successful that it spread to other housing developments and businesses.

Anthea had been a keen recycler for years and pursued her interest by enrolling on the West Sussex County Council Waste Prevention Advisor programme delivered by the University of Brighton. So then when she was living in Walstead Court extra-care housing facility and saw piles of bin bags in the ‘rubbish room’ destined for landfill, she knew something could be done about it.   

With the support of the housing manager, Anthea showed residents and staff how to recycle food, garden and paper waste using three Green Johanna composters.

Her tutor at Brighton, Dr Ryan Woodard, had told her about Green Johannas and she thought they sounded ideal.

‘It was essential to get everyone on board though,’ she says.

 Anthea, front right, with other keen composters and the Green Johanna.

The workshops worked a treat. Waste disposal routines were transformed, as was the rubbish room, now that it was clear of bin bags containing food waste.

 Before long the residents were making their own compost and growing their own food and flowers. ‘We grew the most beautiful tomatoes,’ Anthea remembers.

Anthea approached the task methodically, weighing waste and tracking residual waste.  Waste to landfill was reduced by 55 per cent, black bin bags were reduced from three to one per flat per week. Over a six-month period 280 kg of food waste was diverted from landfill.

The communal gardens were not the only things that blossomed. Residents and staff reported that personal well-being and community spirit also flourished. The projects helped to keep people mentally alert and physically active, through taking waste out to the Johannas, crunching up cardboard containers etc. It also gave neighbours an added reason to chat to each other, acting as a conversational ice-breaker.

Anthea was then asked to introduce similar schemes to other housing associations and businesses. She also ran trials for DEFRA (Department for the Environment, Food and Rural Affairs) and won the Gatwick Diamond Green Champion award for her environmental work.

She then decided to try the same method of community food waste recycling in a very different place – her native South Africa. Here she introduced composting to struggling townships as part of her work with the Dreamcatcher South Africa Foundation that she had set up in 1991 to alleviate poverty by creating employment. In the community, waste was historically burnt at the dumpsite having a devastating impact on the environment and public health.

Anthea, second left next to Sir Trevor McDonald, receiving the Gatwick Diamond Green Champion award.

On a trip back home, she took three Johannas as luggage instead of suitcases, wrapping her clothes around the Johannas’ circular sections. Using the same training methods as in East and West Sussex, she installed three Johannas in a communal garden managed by local women known as Kamammas (a term meaning matriarch, or community leader).

Anthea says the Kamammas quickly took to working with the Johannas.

 ‘They found the composters didn’t attract dogs or vermin and they were delighted when they saw the quality of compost that was produced and the food they could grow with it.’ This trial was then scaled up to introduce another 25 Johannas.

The food that is grown with the Johannas’ compost is used in the women’s work providing tourists with traditional South African cuisine.  

A Kamamma introduces tourists to traditional South African cuisine.

Anthea divides her time between the UK and South Africa, and she is still in contact with the people she got composting back in the South of England. She is delighted – but not surprised – that the schemes she helped to implement are still going strong.

‘Any system must be sustainable, otherwise there’s no point. To bring about real change you have to go truly local. You need the people to make it work.

‘It takes around three months to introduce a composting project. After that people can stand on their own two feet.

‘Once you give people the skills, knowledge and confidence they become compost evangelists!’

After all these years, Anthea is still a big Johanna fan.

‘We used many other composters before settling on the Green Johanna. I underpin everything with baseline research and I knew the Green Johanna was the one.’

She still loves introducing beginners to composting.

 ‘They might know nothing now but you know they soon will. People become fascinated to know about all these little creatures in the composter doing their work.’

She firmly believes that if you pay attention to what’s happening in your composter you will learn  how to ‘speak compost’.

‘You soon learn to tell if you need to do something to bring good conditions back. If you haven’t enough garden waste, you can use paper product waste, such as toilet rolls, cardboard, shredded paper. If the contents look dry sprinkle a little water on top.’

The Johanna may have been designed in Sweden to cope with harsh Scandinavian winters, but it has happily adjusted to the South African climate, often turning ‘psychedelic green’ in the sun.

Whatever the shade, it’s still doing a great green job for the planet, wherever on earth it happens to be.  

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