Which composter is best for me?

An image of a green johanna

If you’re new to composting it can be difficult to know which bin (or system, if you like to think in systems rather than bins) is best for your home and lifestyle. Our handy guide can help.

Food waste composter/digester

The Green Johanna Food Waste Composter and Green Cone Food Waste Digester are both designed to accept foods that regular garden composters don’t, such as cooked food, meat, fish and dairy, so all your food waste can go in together. Compare them to see which one best suits your needs.

Green Johanna Food Waste Composter

  • Produces compost.
  • Also accepts garden waste.
  • Added waste should be a balance of nitrogen-rich content, commonly called Greens, (food waste/fresh grass cuttings/fresh green leaves) and carbon-rich content, commonly called Browns (chopped branches and twigs/wood chips/dead leaves/shredded paper and cardboard).
  • Comes with aerator stick provided to aerate the contents regularly.
  •  Ideally placed on soil or grass
  • One Johanna accepts the average food waste of a household of five and the garden waste from an average-sized garden.
  • With hot composting techniques, higher temperatures are reached than with regular composting.

Green Cone Food Waste Digester

  • Must be dug into a hole in free-draining soil (not clay or chalk).
  • Accepts all food waste, even bones.
  • Doesn’t accept garden waste or paper waste.
  • Doesn’t produce compost – instead it produces nutritious water which drains from its underground basket and feeds surrounding soil.
  • No turning or stirring required.
  • Uses solar energy so requires a sunny spot.
  • Comes with kitchen caddy provided.

Lack of space?

Worm farms

Worm farms, also called wormeries, are ideal for small-scale composting and for introducing children to the fascinating world of worms, which is an education in itself.

  • Require a sheltered spot.
  • Worms will digest many kinds of foods cut up into small pieces and other kitchen waste such as shredded paper, egg cartons, scrunched up newspaper.
  • A little management is needed to maintain the ideal environment for your worms, so be sure to read the instruction booklet.
  • Produce excellent worm-made compost – vermicompost – for your garden.
  • Learning fascinating facts about these tiny eco-heroes is sure to turn children into composters of the future.

Bokashi Bins

  • Kitchen food waste bins that can sit on a worktop or under a sink and accept all chopped-up food waste.
  • Food waste is fermented, resulting in a pre-compost mixture which can be added to a compost bin or wormery, buried in soil in the garden or in large planters in order to break down into compost.
  • Requires the addition of friendly bacteria in a bran or spray to accelerate fermentation.
  • When full of food waste, the container is left sealed for two to three weeks for fermentation to take place anaerobically (without air).
  • Nutritious liquid is drained from a tap at the bottom of the bin and can be used diluted as plant fertiliser or concentrated as organic drain cleaner.
  • Bokashi comes from the Japanese term for ‘fermented organic matter’.

Choosing a compost bin – by the experts

This advice – in note-form taken from a webinar by master composters from Garden Organic – provides extra help.

Green Johanna – reaches higher temperatures – as an enclosed unit it offers greater rodent protection – the twistable top controls ventilation – the solid perforated base means liquid can drain out and micro-organisms can enter – if adding meat, add small amounts, mixed with lots of greens and browns – aerate the top layer every time you add materials – for speedier composting an insulating jacket is available. An alternative way of taking compost out, rather than accessing through the hatches, is to loosen the screws and lift off one or two sections.  Composting slows down in winter but the Johanna continues well and does better than other composters.

Wormery – small and self-contained – ideal for small amounts of waste – year-round composting – can be indoors – worms eat the bacteria on the organic matter – no spicy foods or citrus, only small amounts of meat – food scraps are placed on the top section, casts fall to the bottom. Use the worm-made compost on pot plants or round trees and shrubs. NOTE: If the liquid that is produced smells bad it has gone anaerobic and should be flushed away.

Also:

  • Wormery compost is a great improver to shop-bought compost; you can buy the cheapest of composts but turn it into black gold with the addition of your vermicompost.
  • Sheds are not a good place to house a wormery due to temperature fluctuations – a garage or indoors is better.
  • If you need your worms to move out of way as you harvest casts, add melon or banana – worms love these and will obligingly wriggle over to them.  
  • Don’t forget that with a wormery you are responsible for living creatures.
An image of a toddler using a worm farm. She looks very happy!

Bokashi bin – ferments waste instead of composting so the contents need to be transferred to a composter after a couple of weeks – this pre-compost  acts as an activator in your compost bin – Bokashi bran is needed – fermented contents of the bin will still be recognisable (some people expect compost) – produces liquid which can be used as a drain cleaner or diluted as fertiliser – good to use two bins to keep the process going – ongoing bran purchase required.

Man emptying food into a bokashi bin

Top 10 tips for composting in schools

Composting is a fantastic opportunity for communities to get together to create a greener environment.

Nowhere is this more valuable than in schools, where children can be taught skills that will last them a lifetime.

Composting enables people to take responsibility for their own waste and deal with it in the most environmentally-friendly way – onsite where it is produced – reducing the energy and cost required to transport it further afield for treatment.

 When people compost they become aware of how much waste they produce; as a result they tend to waste less and recycle more.

What is composting?

Composting is the natural process that occurs when insects, worms and micro-organisms break down organic waste (food scraps, garden waste, paper waste) into a nutritious substance – compost – that can be used to feed soil and plants.

By managing the composting process, we help the micro-organisms to thrive and produce compost faster.    

What are the benefits of composting?

Composting is one of the most worthwhile things you can learn. There are only a few rules, and you only have to learn them once – the laws of nature don’t change. This knowledge will serve you well through life.

Composting:

 * creates free nutrient-rich soil food for your own use

* retains moisture in the soil, so reduces the need for watering

* helps plants to grow stronger and healthier

* cuts the amount of waste sent to landfill or incineration

* reduces your carbon footprint

* has a positive impact on the environment

*  inspires children to become composters of the future

How to make it work

Compost bins are not ordinary bins; some degree of management is needed and there are a few golden rules to follow.

Experience has taught us to give composting communities the following advice:

  • At least one person/member of staff should have overall responsibility and check in on the composter every couple of days to prevent issues developing.
  • Ensure as many people as possible have access to an instruction manual so they get to know the three golden rules: the balance needed between materials; aeration; moisture levels.
  • In a school, composting should ideally be a whole-school project. For example, a lot of carbon-rich materials will be needed and it’s much easier if this can be stored in lidded containers so it’s ready for use. This can prompt fun activities such as cardboard tearing sessions. Children could also bring cardboard from home to get parents involved too.
  • To educate the whole school – staff as well as pupils – put up posters giving basic composting information for everyone who will be adding organic waste to the bin. We have A3 posters available for schools and groups, or children could design their own.  
  • Help everyone to understand that every time a caddy of food waste is added to a compost bin (adding nitrogen-rich materials) this should be followed by an equal amount of carbon-rich materials.
  • Many schools produce a lot of fruit waste, especially in the younger classes, and this needs particular attention as it has a high water content which can create a soggy mess if it’s not balanced with appropriate materials and aerated well.  Sawdust works well as a biofilter to absorb unpleasant smells. Fruit waste and sawdust should be added in thin layers and mixed well.
  • It’s a good idea if someone can keep the composting going during holidays by taking waste from home every couple of days so the bin continues to be fed.
  • Teach children that micro-organisms are living creatures, and the composting process is all about nurturing them.
  • Our blog – Compost School – a guide for absolute beginners – is a useful aid for lesson planning. It’s written simply for children to understand but is also aimed at anyone who may not have composted before.
  • Master composters are people who are passionate about composting and have trained as volunteers to share their composting knowledge. They visit schools and groups to offer advice. Check with Garden Organic – www.gardenorganic.org.uk – to see if there are any in your area.

If all goes well, your composting project can expand to compost even more waste by using several compost bins or a Ridan giant tumbler, which has a cog and gear system that makes the handle easier to turn.

 Get a ‘compost chief’!

Projects involving a lot of people can hit problems if composting methods are not followed by everyone.

Occasionally, Green Johannas have been used in schools as general wastebins for food waste, without the necessary balance with carbon-rich materials, and this has inevitably led to problems. This has usually been the result of there not being a nominated ‘compost chief’ in charge.

Disappointing experiences give the impression that composting doesn’t work, which isn’t the case, so we are keen to help where we can.

What about the Green Cone?  

If you think a Green Cone Food Waste Digester might suit your aims, consider the following points:

  • You need a sunny spot in well-draining soil (not clay or chalk) where you can dig the hole required for the Cone’s underground basket.
  • One Green Cone can accept the food waste of the average family of four – about 1kg per day.
  •  Food waste lands in the underground basket; once the underground basket is full, you should stop adding waste until there is space in the basket for more.
  • Regular additions of accelerator powder are recommended – aim to use one sachet per month. Accelerator powder contains beneficial bacteria which digest the waste and boost the breakdown process.
  • As this is a food waste digester rather than a composter, no compost is produced. Instead, a nutrient-rich liquid seeps from the Cone’s underground basket and feeds surrounding soil.
  • The Green Cone doesn’t accept garden waste or paper waste.

Helpful advice

Some people are put off composting because of a fear of pests, but there are steps you can take to make a compost bin and the surrounding area so unattractive to unwanted visitors that they will go somewhere else instead. Read our blogs about how to deter pests and flies.  

How we can help

We are keen to support community composting projects. We can send you several copies of the instruction manuals for the Green Johanna and Green Cone so they can be shared out, as well as colourful A3-size posters about the Green Johanna.   Contact us at [email protected].

Why should I compost?

‘I don’t garden so why should I compost?’ This was what a friend said to me recently.

Where to start to answer this question?

Composting is an obvious activity for gardeners – you make your own top-quality plant food by recycling your organic waste.

 Like my friend, I too am no gardener.  I started growing a few things during the pandemic and finally realised when I saw the transforming effect of plants why gardeners do what they do.   

But the point I tried to make in answering my friend was that it wasn’t for the sake of plants that I started composting but for the sake of the soil itself.

A health soil sign that reads 'Healthy soil is the beating heart of organic growing - full of life and support life'.

 When I learned a few years ago what magical powers compost has in rebuilding the poor, degraded earth of the Earth, I realised that composting was a no-brainer.

The health of our soils is fundamental to life as we know it, but according to the charity Garden Organic, half the planet’s topsoil has been lost in the last 150 years.

And yet there’s something we can all do about it! Home composting might seem a small act on an individual level but multiplied by millions it’s huge.    

Climate crisis ally

For instance, did you know that one of compost’s superpowers is to help soil capture carbon in the atmosphere and pull it down into the ground? Along with oceans and forests, soil is an important carbon storage medium. And yet we’ve been letting the organic ingredients for compost rot in landfill for years, emitting greenhouse gases instead of capturing them. It makes no sense to throw nutrients away as rubbish when we can easily separate them to speed up the natural breakdown process.

 According to WRAP, the waste reduction charity, a home composting bin can divert approximately 150 kg per household per year of organic waste from landfill or treatment centres.

Save our soils

The minimum we can all do is to ensure that soil is not left bare. Bare soil is vulnerable to erosion, weeds and carbon loss.

  • Cover soil with mulch and just leave it. Chuck it on in layers of around 5cms. You can cover borders, around shrubs, trees and bushes. Worms will come up and take the compost back down into the earth where it will improve the soil structure.
  • Compost also helps worms to thrive, and they need all the help they can get, under onslaught as they are from chemical sprays, artificial grass and the paving-over of gardens.    
  • Give your lawn a boost by spreading compost thinly over it. Worms will pull it down into the soil, which will boost soil quality and by extension the grass.

Benefits for us

Michael Kennard (pictured) the founder of the food waste collection service Compost Club, has studied soil biology and is keen to spread the word about how soil is the foundation of our health. If we destroy it, it’s to our detriment.

‘Everything is a reflection of the soil,’ he says. ‘If the plants have that natural cycle going on, they’re really healthy. When we eat those plants, that’s what informs our gut health.’

Other benefits that compost provides include:  

  • preventing erosion
  • improving drainage
  • encouraging worm activity. Studies have shown that the simple act of introducing worms to degraded soil in poor regions of the world has increased plant yields by 280%.
  • preventing flooding. As more and more gardens are paved over there is less and less earth to absorb heavy rainfall. In order to slow down runoff and encourage water infiltration into soil, swap paving for plants and mulch, or ensure paving is permeable. In his book The Science of Gardening, Dr Stu Farrimond says that covering soil with mulches in late autumn protects it from pummelling winter rainfall (each bullet-like drop travels up to 20mph).

Benefits for plants;

Used on plants, compost holds on to important nutrients, improving the plant’s quality while also protecting it from pests and diseases.

 As compost breaks down further, it releases important nutrients into the soil, including the main nutrients that plants need: nitrogen, phosphorous, and potassium. Compost also increases the number and variety of beneficial bacteria and fungi in the soil, which helps plants to grow.

The ability of compost to absorb water is important as it’s able to slowly release water to grass and plants so they need watering less frequently. This is obviously vital in hot weather and droughts. Studies on compost’s water-retaining abilities have shown that for every 1% of organic matter content, soil can hold 16,500 gallons of plant-available water per acre of soil down to one foot deep.

Compost also helps water to get to plant roots more effectively by reducing crust forming on soil, so water can get into the soil more easily, and by helping to disperse water laterally from where it hits the ground, which means it will evaporate less quickly.

But I don’t have time to compost

Composting can be as time-consuming as you want to make it. If you’re pushed for time, go for cold composting.  If you want to invest a bit more time and effort, try hot composting, which means a wider variety of food waste can be added to the bin and compost produced faster.  

Or use bokashi bins, which ferment food waste thanks to the addition of beneficial bacteria in the form of a bran or spray. Once it has been left to ferment for a couple of weeks, this pre-compost mixture can then be added to a composter.

People whose local council operates a food waste collection might think, Well the council composts my food waste, so I don’t have to. But many people take the view that if they are already separating food waste to leave out for the council to collect, they might as well compost this valuable resource themselves at home for the benefit of their own garden or allotment.

 By 2026 all councils throughout the UK will have to comply with regulations requiring them to operate separate food waste collections.  

There are around 15 million gardens in the UK. We call them ‘our’ gardens but of course that portion of the earth isn’t really ours – we’re merely its custodians for a while.

Once you see the difference you can make to that tiny patch of the planet, without much effort, you can’t help but become a compost convert.

Julie

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