FAQs

A well functioning compost bin should hardly have an odour. Any smell should be fresh and earthy. You have probably added too much nitrogen-rich waste, such as grass clippings or food waste. Remedy this by adding plenty of carbon-rich garden waste (shredded twigs/branches/autumn leaves/wood chips),  shredded or scrunched paper and cardboard. You also need to get oxygen into the mix by stirring well with the aerator stick. You may also need to thoroughly aerate the compost deeper down by using a hoe or garden fork. Take a small batch of the finished compost or half-composted material from lower down the unit and sprinkle over the top.

If you have large amounts of fresh grass clippings (nitrogen-rich) this should not be added all at once and should be well balanced with carbon-rich materials such as shredded autumn leaves and newspaper. 

The Johanna is designed for a household of up to five people with the compostable waste produced from an average garden. However, since this is extremely variable, if you believe you are filling it too quickly it would be recommended to have a second Johanna. A garden produces less waste in winter, so if you have space you could store some waste to layer in with food waste during winter.

As micro-organisms break down waste and multiply, they generate heat. As the temperature in the compost fluctuates, the types of micro-organisms present also change. This diversity is important. How warm the compost gets depends on what you have put in together with levels of oxygen and moisture. Different micro-organisms work at different temperatures. 

There are three major phases in successful composting – mesophilic/thermophilic/maturation.

The mesophilic phase occurs at the start when decomposition is carried out under moderate temperatures by mesophilic organisms. The thermophilic phase occurs as the temperature rises and various thermophilic (heat-creating) bacteria carry out decomposition at temperatures of 50-60 degrees Celsius. The maturation phase occurs when the temperature starts to decrease as the supply of high-energy compounds dwindles and mesophilic bacteria once again predominate.

The optimum working temperature in the Johanna when wearing the Insulating Jacket will usually be around 40-60 degrees Celsius. If temperatures reach 70 degrees, steps should be taken to lower the temperature, such as by removing the Insulating Jacket and increasing ventilation by twisting the lid to the maximum setting. Temperatures of over 70 degrees will be too hot for the micro-organisms to survive.

Yes, if you add paper product waste (shredded paper and newspaper/ripped-up cardboard, toilet roll tubes, egg cartons) and/or sawdust and wood chips. These provide carbon to balance the nitrogen in food waste. It would be useful to store these materials so you have carbon content readily available for each time you add food waste. Most people find they have more nitrogen-rich content than carbon-rich so they stockpile carbon sources so they have it ready for when needed. 

 Cardboard should be torn up (with labels and stickers removed), paper and newspaper should be shredded or scrunched up. Toilet roll tubes and corrugated egg carton bases can be left whole in order to create air pockets.

Wood chips are useful as they hold structure and create pathways for air.  It can be helpful to have a bag of wood chips next to the compost bin. After emptying the kitchen caddy, add a caddy of woodchips etc.

If adding large amounts of sawdust, take care to separate it out in order to avoid clumps forming.   

Twigs, branches, dried leaves, sawdust, woodchips, paper, cardboard, garden soil.

Food waste, coffee grounds, fresh grass clippings, fresh green leaves.

The time required for waste materials to break down into compost depends on:

• the volume of material; a greater volume will maintain the thermophilic stage for longer. 
• the particle size of the inputs; smaller items break down faster.  
• the amount of mixing and aeration.

Depending on conditions, the usual time using the Green Johanna is 4 – 6 months. Using the Insulating Jacket, temperatures will remain high for longer and compost will be produced quicker. 

You need to keep your compost moist; ants are attracted to dry, soil-like materials. Gently add water to your mix using a small watering can and stir in well. You want the consistency to feel as damp as a wrung-out bath sponge. If you squeezed a handful of compost between both hands only a drop or two of liquid should come out.

This is an indication of poorly covered, nitrogen-rich content.  It is likely that the consistency is too wet. Add carbon-rich garden waste such as shredded twigs/branches/woodchips, shredded or scrunched paper and cardboard and mix in well. This will absorb some of the excess moisture and add air throughout the mix. Adding Bokashi Bran will speed up decomposition. Ensure food waste is always covered by carbon-rich materials. Deter flies by adding a surface layer of soil or compost to the top of the bin’s contents.  Also check that you are shutting the lid securely when filling up the composter.

The following blog contains tips for preventing and dealing with flies: Tips for fruit fly nuisance, Green Johanna, Green Cone (greatgreensystems.com)

Depending on the temperature and stage of decomposition there will be: worms, mites, beetles, woodlice, millipedes, centipedes, springtails, false scorpions, nematodes, earwigs.  There will also be a whole host of bacteria, micro-organisms and fungi that are invisible to the human eye.

There are several reasons for a composter to stop working:

• Too much dry, carbon-rich material, such as autumn leaves, twigs and paper, meaning the contents may have dried out. Add nitrogen-rich material, such as food waste or fresh grass and stir thoroughly.  You may need to add a little water using a small watering can or water wand. The ideal consistency is like a squeezed, damp bath sponge. If you take a large handful of the compost and squeeze it, only a couple of drops of liquid should come out. 
•  A lack of material in general will always slow the process down and in some cases stop it completely. Add more waste materials, maintaining the carbon-nitrogen balance, to start up the process again.
• The mix lacks oxygen. Give the whole bin a really good stir and add some finely chopped twigs or wood chips to help with aeration.
• Cold weather and a poorly-fed Green Johanna can bring a halt to the composting process. In winter make sure that you are adding content regularly and the Johanna is wearing an Insulating Jacket.

You can dispose of up to one kilogram of waste per day in a well-positioned and fully working Green Cone. As long as the unit has a healthy population of bacteria, a consistent ambient temperature and a balanced ‘diet’, it can dispose of the food waste created by the average family of four per day.

No, grass cuttings and garden waste will stop the Cone from working properly. For garden waste,  you should consider the Green Johanna hot composter.

Yes, in moderation, if you are not using the residue on a vegetable patch and the Green Cone is not sited close to water sources. Pet excrement must be added to the Cone directly, never in a bag. Bags of any sort, even compostable or biodegradable, will prevent the Cone from working properly. Avoid adding cat litter as this may contain antibacterial agents and its quantity could quickly overwhelm the Cone.

No. The Green Cone is designed to break down waste naturally without assistance.

Yes, although it may slow down a little on darker, colder days. But a little accelerator powder will keep it working as usual no matter what the weather.

No. Any artificial additives will affect the way the Cone’s natural bacteria works to break down the food waste.

With a well-maintained Cone you may need to empty and clean it once every few years. Very little waste residue will be produced. Should the residue build up to approaching ground level and show no signs of reducing, the Cone can be removed to access the basket and the residue can be dug into any suitable area of ground.

Simply hand wash it in warm soapy water. Do not put in the dishwasher.

The Green Cone is a sealed unit and when properly installed, with the top of the black basket and bottom lip of the green outer cone below ground level and the lid shut securely, emits no smell; any smells are filtered out by the surrounding soil. This means there is no obvious attraction for flies and vermin. However, the eggs of fruit flies are already in the skins of many fruits and might hatch out in the Cone. Should this happen, a small squirt of organic fly spray will resolve the issue. It is important that the caddy is always kept well covered in the kitchen to prevent house flies laying eggs in the food waste, which would then be transferred to the Cone, putting flies into the system. Again, a squirt of organic fly spray will clear up the issue without hindering the eco-system in the unit.

Obviously, it is important not to spill food near the Green Cone.

Advice given in the handbook should be followed for the Green Cone to continue working properly:

• Position the Cone in as sunny an area as possible, not a dark, shady area as it is solar powered.
• The surrounding soil must be well drained and not heavy clay or chalk.
• The black underground basket must not be below the water table or in an area where water gathers.
• Accelerator powder should be added to the Cone so that there is enough natural bacteria to keep digesting the waste. This is particularly important in cold weather. If the level of waste in the basket is not decreasing, add accelerator powder, as directed in the handbook.

If the instructions are not followed, the digestion process could turn anaerobic (without oxygen) and the food waste may appear wet and slimy. The solution in this case is to reinstall the Cone in accordance with the instructions.

To correct wet compost we recommend reducing the amount of green waste (fruit, vegetable, kitchen scraps) and increasing the percentage of brown waste (dry grass, leaves, paper).
Generally the mix should be 50/50. However, in the case of wet compost it is necessary to increase the percentage of brown waste temporarily in order to get the mixture balanced again.
Once the mixture is moist (without being wet) it will be possible to revert to a 50/50 composition.
Exposure to sunlight and increased aeration are also helpful in getting the compost back to its correct balance.

If your compost tends to be rather too dry or too wet (or you are not sure how it is going), mixing the contents of the bin now and again gives you the opportunity to adjust the balance of materials. It can also speed up the process if the heap is short of air.
Turning and mixing is made easy with a Compost Tumbler.  However, material in a Tumbler can dry out, and you need to make sure it is sufficiently moist for the composting process to proceed effectively.

The presence of ants can indicate that the compost is too dry. If this is the case, mix in wetter materials or lightly water the mixture.

If you are new to composting, you may just need to be patient.
Composting is a biological process that does take time and slows down in cold weather. It will also be slower if the compost is too dry, or the contents are all rather tough. Try adjusting the moisture level and mixing in grass clippings and other materials that are quick to rot. Chopping up your organic waste before depositing it into your composter will also speed up the process (by exposing more surface area to microbes).

Yes, if ‘Greens’ ( grass clippings and vegetable scraps) and fine ‘Browns’ (shredded leaves and dry herbaceous plants) are composted in a Tumbler that is kept moist, turned regularly and kept in a sunny position
To make compost quickly in a traditional garden compost bin you will need to fill it completely in one go using a good mixture of green and brown materials (chopped up or shredded if chunky). You will notice that the contents of the bin will begin to get hot in a few days (this is a good thing!) Once they have cooled down, mix the heap well with a pitchfork or compost aerator. This keeps the pile uniform in consistency and helps introduce oxygen to the microbes. Keep on mixing every few days until the heap has turned into usable compost.
It is also important to note that external temperatures play an important part in the rate at which organic waste can decompose into compost. This is the reason why composting is faster in summer than in winter.

A large quantity of leaves at once could throw the composter’s carbon/nitrogen composition out of balance. Instead you can add them, wet, into black plastic sacks (or into a simple wire mesh container) and leave them to rot for a year. They will eventually turn into ‘leaf mould’, which is a good soil conditioner and potting compost ingredient. Two-year-old leaf mould makes good sowing compost on its own.

If there is a rodent infestation locally contact your local authority to deal with the problem. If possible site the bin way from fences, bushes and woodpiles and ensure it has a secure, tight-fitting lid. Compost Tumblers offer the added deterrent of being off the ground and fully enclosed.

Slugs are a useful part of the composting process and will stay feeding in the bin. When you finally spread the finished compost any slug eggs that might be present are likely to dry out before they can hatch. A compost bin will also harbour other creatures that eat slugs – so keep composting!

Annual weeds are fine to compost. If they have gone to seed they will still compost well, though you are likely to get seedling weeds growing in the compost when you apply it to the garden. These can easily be hoed off, or you can dig the compost into the soil to reduce germination.
Persistent perennial weeds that spread easily are best kept separate. Put them in a black plastic sack with some grass clippings and leave them in the sun to rot for up to six months. Once all signs of the roots have disappeared, add the sludge to your composter.
Alternatively take them to your local green waste collection site. Large-scale commercial compost heaps heat up to high temperatures that kill them off.

Yes, as long as you take the usual hygiene precautions. Keep any cuts covered, wear gloves when handling compost and wash hands well afterwards.

Yes.  It will compost when mixed with other ingredients.

Tough and chunky items will compost much more quickly if chopped or shredded. A power shredder is great if you have a lot of woody cuttings and evergreen hedge clippings to deal with. Small home shredders are often not powerful enough to be efficient.
It is probably more cost efficient to hire a shredder now and again, or to share a larger shredder with neighbours and friends.

Fresh clippings (whole or shredded) can be used for mulch on pathways or under mature trees. For other uses they should ideally be at least partially composted before use. Given that they usually come in large quantities we recommend keeping them in a separate compost heap.

While many diseases can only survive on living plants, other diseases can continue to prosper in the soil without any viable host. If in any doubt it is a good idea to err on the side of caution and not add the diseased plant to your compost mix.

A Bokashi bin is designed to collect kitchen scraps and initiate the breakdown of organic material.
A compost bin or tumbler is primarily used to convert kitchen and garden waste into usable compost.
If you live in a flat and don’t have a garden, a Bokashi bucket would be adequate, provided you have access to land where you can bury the fermented scraps. Wormeries can also be used for converting many kitchen scraps (not meat, fish and dairy products) into useful organic products and liquid fertiliser.
We find that the best set-up (room and garden permitting) involves using both a Bokashi system in conjunction with an outdoor bin.

Bokashi bins can accommodate all organic kitchen scraps (including meat, fish and dairy products). The addition of Bokashi microbes begins the process of fermentation anaerobically (without oxygen) and minimizes any unpleasant odours. Emptying is only necessary once the unit is filled and has been left sealed to ferment for around three weeks.
The kitchen caddy on the other hand has to be emptied regularly into a Green Johanna, Green Cone, or Compost Tumbler, where the breakdown process will take place aerobically.