There’s compost, and then there’s great compost. It’s as much about what you put in it as it is what you do with it. By simple definition, composting is the process of converting organic, biodegradable material (along with its nutrients) into material that can be added to or used in the place of soil. Primarily used for farming and agriculture, this process commonly relies upon decomposition aided by anything from insects and worms to bacteria and fungi. It’s extremely easy to create compost, but understanding what’s really going on is the key to making to great.
Generally compost is used as a nutrient-rich soil supplement and fertilizer which can be added to plant pots, gardens or fields when their existing soil has a deficiency in the nutrients required by plants for growth. It can be used in the planting stage or even after plants have taken root, as water and weathering will transfer nutrients throughout the soil. Depending on circumstances you can mix it in with existing soil or simply spread a layer on top.
Making compost requires us to force the decomposition process, meaning anything we add to assist this is welcome, but generally you will need two ingredients; fresh organic material which is high in nitrogen, and dead organic material which is high in carbon. When you mix these two together, things start to happen. Microorganisms (like bacteria) will start to show up and consume organic matter, breaking it down and excreting decomposed elements. While worms and fungi help largely with the physical process of breaking material down, bacteria primarily assists in the chemical process of converting broken down material into heat, carbon dioxide and ammonium. Ammonium is the primary form of nitrogen which is used by plants, and they don’t dislike the other bi-products either.
The decomposition process can take place under a variety of conditions and utilize different organisms and bacteria to do so, but we will highlight how to do so using aerobic bacteria (bacteria that needs oxygen), because it is the most simple way to get great results.
So you will need some fresh organic material, dead organic material, air and moisture.
Your fresh organic material (green waste) needs to be high in nitrogen content and can include anything from plant waste (like fresh leaves and grass clippings), fruits and vegetables among other food waste, to even urine (nitrogen rich) and manure so long as it has had a chance to decompose a bit on its own already (to rid it of fecal bacteria and viruses). If using manure, take considerations to make sure it does not contain harmful bacteria or viruses associated with fecal matter. Most fecal matter is not safe for use in agriculture unless it has been treated, so if you are going to use something; use something simple like bird or rabbit manure. If you want to pitch in personally, remember that humans excrete almost all of what a plant would want in our water-soluble urine alone; 90% of the nitrogen, potassium and phosphorus excreted versus the 10% found in fecal matter. That said, a healthy human’s urine alone can be used as a fertilizer in its own right, recommended at a ratio of at least 6 parts water to 1 part urine (as its concentrations can burn living plants). If you want to add it to fertilizer that you are making, just toss it in!
Your dead organic material (brown waste) is essentially just dead weight carbon; one of our “building blocks of life”. Most organic concentrations of carbon tend to be brown and dry, which is why we refer to it as brown waste, but you could still have brown-colored green waste. This can include dead leaves, dead plants, wood, paper, straw, etc.
A good rule of thumb is to create a mixture of 3 parts brown waste to 1 part green waste.
You will want to keep this contained in some way, but that can be as simple as keeping it contained in a pile on the ground. One thing you will definitely want to consider is contamination by disease-carrying bugs or disruption from animals looking for an easy snack. This is why we build (or purchase) compost bins, and often add covers. Covers can keep critters out and heat in, if you are in a region that gets cold. Just like when you cultivate yeast, if things get too cold the microorganisms like bacteria can slow down substantially or even die, which will slow or stop the decomposition process altogether. If you can’t afford a cover or figure out how to make one, make sure you are burying the tastiest green waste to deter pests and critters from just picking it off the top.
Remember that if you want to promote the cultivation of aerobic bacteria you will have to keep your compost aerated which means turning it, digging it up and mixing it in order to distribute air throughout the materials. Composting can be achieved with anaerobic bacteria (which does not require air) but this is almost always less pleasant to be around in both appearance and smell, and can require several additional considerations. You should mix up and turn your compost every week or so.
You also don’t want your compost to dry out. If it does, many of the organisms will not be able to function or live and you can kiss your physical and chemical reactions goodbye. Make sure your compost stays moist and warm. The best way to check this is as simple as touching it, which you should not be afraid to do. If the compost is getting dry, add some water (or even healthy urine, as mentioned before).
If the compost is struggling to stay warm, remember to keep it covered. If you are composting in a cold environment which is proving difficult to work around, try insulating the compost or adding something like a decomposing log to the middle of it. The log will continue to decompose but remain structurally intact for some time, emitting heat and keeping the surrounding compost warm.
Compost is something that you will have to feed until you are working with a volume you require or are comfortable with. Unlike cultivating yeast, it is not something that will grow in size on its own, it will only convert what you add into another form of similar (if not exact same) volume. However that being said you do still have to feed it. If you start your compost by just accumulating waste when you produce it you will need to continue to add material as you go and continue to turn it on a weekly basis. When you eventually reach the volume you want to work with, you will need to stop adding material and feeding the compost so that the organisms working away on breaking it down can finish up their job without having to perpetually move on to new material. If you need to make more compost, start another bin, or pile, or pit. It is not uncommon to have several composts decomposing at the same time.
As you continue to turn the compost on a weekly basis you will notice much of the material starting to break down into soil-like humus, which is what you want. If you let compost continue to decompose its material, it will eventually break down completely into this consistent, fluffy, aerated soil mixture. Minus a few solid non-biodegradable elements that may have found their way into the compost, you are good to go.
Use your new compost mixture to fertilize soil for agricultural use and you will see the results in your plants. They will grow bigger, faster and stronger. That being said, compost is not the only way to fertilize soil and plants, but it’s one of the easiest and it makes use of the waste we are generating (and finding) anyway.