Introduction: Compost

Compost is obtained using all sorts of leftover organic materials. The best compost is obtained by keeping air, moisture, and temperature ideal within the mix of materials. This manual is aimed at composting in a compost bin and informs you on which materials to compost, and how to manage air, and moisture. This should result in an optimal process where the temperature within the heap of compost can rise to as high as 60 degrees Celsius (140 Fahrenheit).

Step 1: Construction

When constructing a compost heap, diversity of materials and aeration are the main elements to keep in mind. Temperature and the amount of moisture in the heap can be adjusted at later stages and need time to develop after construction of the heap.

Starting the heap
Start the compost heap with a layer of several decimeters (about a foot) of coarse materials, such as large branches. These help aerate the lower parts of the compost heap, which will become quite dense during the composting process.

The actual compost heap consists of a mix of so called green and brown materials. Green materials provide the initial heat in the heap, are typically moist, and rich in nitrogen. Examples of green materials are fruits, vegetables, fresh grass clippings, and coffee grounds. Brown materials provide the fibers in the heap, are dry (or dried up), and rich in carbon. Examples of brown materials are autumn leaves, dead plants, weeds, and sawdust. Materials with the right mixture of carbon and nitrogen, like manure, straw, and hay, can be used interchangeably with green and brown layers.

Create a mixture using 1-3 parts of brown material on 1 part of green material. This ratio has been proven to result in a good initial level of moisture, and also starts up the composting process which will generate the needed heat for the bacteria which turn your materials into compost. Mix the brown and green materials so carbon and nitrogen can interact with the bacteria.

Closing the heap
Close the heap using dry materials. Flies are usually attracted to the more moist parts of the heap of compost, and in particular to food scraps. Make sure these materials are mixed well inside the heap and close off the heap with for example some fall leafs.

Step 2: Maintainance

Although the initial heap of compost can provide good circumstances for the process, (small) adjustments may be necessary to keep the process going as good as possible. All of the adjustments in this step help maintain optimal aeration and moisture in order to increase the process speed (and temperature as a result).

Keeping the heap aerated
Stir and turn the mixture on a regular basis. Turning the whole heap should be done monthly, while stirring the mixture with a pitchfork can be done as often as you'd like. This will increase the access to oxygen for the bacteria creating the compost. When multiple bins are available, you can turn the whole heap from one bin to the other.

Smelling the heap
A nasty smell can be developed by a compost heap when there is not enough air to facilitate the process. Aerate the heap if this should occur. Another possibility is that the heap became too moist. Therefore, also test and possibly adjust the moisture level.

Adjusting moisture level
It is wise to keep your composting materials moist enough to keep the process going. Watering the heap once a week is a good start. If your heap is too moist, add some brown material to the mixture. Dry material can absorb some of the moist, which decreases overall moist level. If the heap is mostly too moist, adding a lid to the heap can solve the problem.

Testing the moisture level
When the material is turning into compost and looks more like soil, you can test the level of moisture using the following method. Take one hand of material, and squeeze it. If it falls apart like sand (or if the mixture contains ants), it is too dry. When water drips out of the hand of material, the material is too wet. When the hand of material keeps together, and does not lose water as if it where a sponge, you are the happy owner of good compost.

Step 3: Harvest

Turning the material into compost will take at least a couple of months and depends on the conditions discussed in the previous step (moisture and aeration) and on the mixture between carbon-rich and nitrogen-rich materials. As soon as the pile feels like dry garden soil and smells like fresh forest soil, the compost is ready to use on your garden. Another indicator is when the materials are no longer recognizable; no more material can then be processed into compost and you can use what you have.