Composting correctly

Composting – what exactly is that?

During the composting process, organic matter (carbon compounds) is decomposed under controlled conditions by soil-dwelling organisms under the release of carbon dioxide. As a consequence, important plant nutrients such as nitrogen, phosphate, potassium and minerals are freed up, turning the finished compost soil into a valuable fertiliser. In compost piles or containers, we make use of this natural process which takes place on every forest floor on a daily basis by collecting and layering the organic material to be composted and optimising the conditions for the micro-organisms involved in the process of composting through a controlled supply of oxygen.

Compost describes partially decomposed organic material or even that which is still to be decomposed; humus, on the other hand, is organic material that has been entirely decomposed, i.e. mature compost. An essential component as well as a basic requirement for a successful composting process lies in the mixing ratio of the compost components. The main differences here are made between brown parts and green parts. Brown parts refer to the carbon components in the composting process, such as woodcutting and sawdust (hence the litter used in TROBOLO toilets). This particularly serves the compost as a structural material and enables a loose layering of the materials which is essential for the supply of oxygen. Green parts, on the other hand, refer to the nitrogen components, such as food waste, manure (faeces), grass cuttings or withered flowers.

For effective fertiliser humus, a mixing ratio of about 20-25:1 should be aimed for (20-25 brown parts : 1 green part). If the proportion of carbon components (brown parts) is too high, the decomposition proceeds more slowly. However, if the proportion of nitrogen components (green parts) is disproportionately high, the decomposition process takes place very quickly, but only a few stable humus compounds are established.

Which materials you can add to the compost in addition to those already mentioned and which materials you should not compost is explained in more detail below.

What can be composted?

The quality of the compost is largely influenced by the raw material. Not everything that is produced during gardening or in the household is suited for composting since it can impede the composting process or burden the resulting humus with harmful substances. In addition to the selection of the material to be composted, the layering is also crucial for successful conversion into fertiliser. Green and brown parts should be well mixed, for instance. On the one hand, this ensures adequate ventilation of the compost material and, on the other hand, it prevents the fresh components from rotting quickly if the layers are too dense.

The following materials can be composted without hesitation:

• Fruit and vegetable leftovers
• Foliage
• Fresh parts of plants such as grass clippings
• Manure or toilet waste of your TROBOLO
• Old wood
• Straw
• Tea leaves
• Coffee grounds
• Toilet paper
• Eggshells (in small measures)

The following should not be composted:

• Large amounts of pine needles and twigs
• Printed paper
• Oak and walnut tree leaves
• Fresh roots of weeds (nettles, couch grass, ground elder)
• Cigarettes and ash
• Cooked food leftovers, meat, fish, fat, bones

Notes: Kitchen paper (i.e. to line the collection container for kitchen waste) as well as the toilet paper from your TROBOLO can both be composted without any issues. Wrapping paper or paper with colourful print should not be composted, however, as these may contain large amounts of heavy metals.

Fir branches and needles as well as some types of leaves like those from oaks or walnut trees decompose relatively slowly which is why you should not use large amounts of these. Small quantities are good to compost. The composting of fresh weed roots and seeds should be avoided. If these have been thoroughly dried out, however, they can then also be added to the compost.

Food leftovers, particularly those specified here, can cause rats to spread which is why it’s usually not recommended to use these for composting. Eggshells are mineral-based which means they don’t rot and should therefore only be added in small amounts and only if crushed into small pieces. Yet in small measures they can be useful for enriching the compost soil with lime. Ultimately, however, it’s also the material of the compost container used that will make the difference.

Thermo composters usually generate high enough temperatures to allow even for materials that are dubious for open piles, such as roots of any weeds, to be added without hesitation.

Benefits of composting

Composting has less to do with the disposal of organic waste, but rather with the refinement thereof into effective humus which can be used as a fertiliser in the garden to help plants grow healthily and become more resistant. This is based on the fact, that mature compost not only improves the quality and structure of the soil but also its water storage capacity. What’s more, by adding the humus, the organic matter will be returned to the soil. This way, nutrients that have originally been absorbed by plants from the earth via their roots and eventually reach our metabolism through food intake are returned to the earth and thereby close the nutrient cycle.

Composting doesn’t only contribute to sustainability in this respect – the overall produced household waste can be reduced by a third due to consistently separating and composting the organic matter. By using a TROBOLO Composting toilets and its waterless functionality as part of the separation system, you also save valuable drinking water and thus make a major contribution to sustainability.

What should be kept in mind when composting?

If you want to compost your waste in your own garden correctly, then there are a number of points you should consider before obtaining compost as well as throughout the composting process in order to reap the benefits of fertile humus..

Composting location:

Correctly prepared compost should be located in an easily accessible place of the garden. When applied and maintained properly, it will produce little or no unpleasant odour at all. In order to consistently prevent potential and mostly short-term odours, you should leave plenty of space between the compost and windows, doors, terraces and neighbouring houses. Finally, it’s best to place the compost in a semi-shaded location where it is protected from direct sunlight (especially around midday) and wind, but where the occasional sunray will still be able to reach it. This way, you effectively prevent unwanted drying up in the long run and still provide your compost with a little occasional warmth which benefits the decomposition process.

Compost container:

If you don’t want to set up a compost pile where the materials would be added onto an open pile without a container in layers, then there are a few aspects you ought to consider when choosing the right compost container. Firstly, it’s important that the compost is sufficiently protected by a cover against weather conditions and troublesome animals like rats. This will also prevent rainwater from seeping through the compost and will reduce any leakages of nutrient-rich excess water and, if you’re composting toilet waste, the development of black water. What’s more, you should place the container onto a flat, even piece of wire fence with a close mesh to prevent rat and mice infestations. On top of that, the container will need to have a sufficiently large capacity due to the long decomposition period. Finally, natural air supply should be ensured. Although the oxygen supply is guaranteed thanks to the correct layering of the compost and the sufficient use of structural material (brown parts), this should also be one of the container’s functionalities.

In addtion to the TROBOLO composter which is made from solid wood and boasting a capacity of 300 litres, also the TROBOLO thermo composter (100% recycled plastic, 400 litres capacity) offers ideal conditions for long-term decomposition of compost materials due to its isolating outer walls and optimal venting system.

Temperature:

The composting process should ideally take place aerobically throughout, i.e. under influence of oxygen. During the process, the temperature will rise significantly as a result of the active microorganisms’ metabolic activity. Towards the end of the decomposition process, the temperature will drop again, causing small animals like mites, woodlice and earthworms to settle in the compost. The changing temperatures create optimal conditions for the respective microorganisms and small animals involved in the composting process. In order to maintain these conditions, you should check the temperature of your compost every now and then and turn it if the temperature rises above 60°C or above 38°C. In the case of insufficient oxygen supply, the decomposition process will move to an anaerobic stage. This should be avoided by any means, however, as the activity of the microorganisms decreases due to the lack of oxygen or only those remain active that can survive in low oxygen content environments. As a result, the decomposition process will come to a halt, the materials begin to rot and will produce an unpleasant odour. It is therefore advised to regulate the oxygen content and temperature by simply turning the compost material from time to time.

Moisture

In order for the microorganisms involved in the decomposition process to feel comfortable and do their job, it is important to ensure sufficient warmth as well as a certain basic moisture level in the compost. If the compost is too wet due to materials with high water contents or if it’s too densely layered and thus poorly aerated, then anaerobic microorganisms will dominate, i.e. those that can survive without oxygen. As a result, the decomposition process will slow down and the compost will start smelling foul or fermented very quickly. If the compost is too dry, however, the decomposition process won’t be able to start and important fungi and germs will be at risk of being blown away with the wind. A moisture of 40% – 60% – approximately the moisture of a squeezed sponge – is thereby optimal for the bacteria and should be maintained by a regular turning of the compost material, the correct composition and potentially by slightly moistening the compost.

Maintenance of the compost pile

After a certain amount of time has passed, you should turn over the compost with a shovel or pitchfork completely to ensure the materials on the sides of the compost container or pile will be decomposed. The exact time of this varies depending on the chosen type of compost container. If you’re using a hot composter, this will already be necessary after about two or three months, but in the case of a conventional closed composter, the point in time will be slightly later. You can use the volume of the compost as a guideline as it will have decreased significantly when it’s ready to be turned. In order to ensure sufficient air supply and thereby guarantee optimal conditions for the microorganisms creating the compost, a regular turning of the compost at intervals of a few weeks is then recommended. When working on the compost, you should pay close attention to hygiene, i.e. not drink anything at the same time, avoid open wounds and wash your hands once the work is done.

Duration:

Fresh compost which is extracted as mulch material after around 6 months usually has larger amounts of nutrients and biologically active substances than mature compost – however, there is a risk that the germs it contains have not been completely eliminated yet. These can then contaminate the beds and patches on which the fresh compost has been applied and pollute them with pathogens. This would have particularly serious consequences if you were to apply the fresh compost to vegetable patches as the pathogens could eventually be directed into the metabolic system via food intake. In order to avoid these risks, a decomposition period of at least one year is recommended. The compost should then have completely matured, which becomes apparent thanks to the typical smell of forest soil.

In addition to this, the compost should be dark and crumbly and should not contain any chunky elements anymore. However, if you have added shredded branches to it, you will still find remnants of these in your compost after the one-year decomposition period as they take considerably longer to decompose. You can either add them to your patches together with the compost or, if you prefer, you can simply sift the compost to remove the shredded branches.

You can find further information here:

• Federal Environmental Agency: Compost, home composting
• Nature Conservation Association: Composting correctly. Suggestions for home gardeners and allotment holders