The world is truly made up of such amazing creatures. I was recently reading a book by Dr. Elaine Ingham and it occurred to me that we are taught that plants will take the nutrients they need from that soil and use it to grow. Chemical companies the world over will have us believe that we need to continuously add fertilisers to the plants to ensure there are enough available nutrients for them to grow. This misnomer is based on the presumption that the soil is not growing or living of its self. Dr. Elaine Ingham challenges this preconception and in fact, she turns it on its head. What has just been described is DIRT, not soil. As you can see from the image above there are numerous organisms or microbes living in the soil. For us to be able to grow strong and healthy plants we must feed the microbes and other life within the soil.
Why feed the microbes?
Dirt has no life. It is for all intents and purposes just dust. There is no discernable life to be seen under a microscope. On the other hand, the soil is teeming with life and that life is there to support your plants.
Plants work in symbiosis with the microbial population. Those microbes both take from and exchange vital components with the root systems of your plants. Plants require minerals and complex sugars to grow, microbes are the teeth of the soil. They reduce the dead and dying components into complex sugars and minerals the plants need. Without microbes, your plants will likely die.
How do we feed the microbes?
Feeding the soil microbes is relatively easy we just need to ensure that they have enough decaying humus in the soil. Sounds easy right? Unfortunately, it is both easy and difficult at the same time. This is due to many factors but some include desertification, rainfall, modern cropping practices and, climate change to name just a few.
‘Soil is essential for the maintenance of biodiversity above and below ground. The wealth of biodiversity below ground is vast and unappreciated: millions of microorganisms live and reproduce in a few grams of topsoil, an ecosystem essential for life on earth…’
Our soils have been depleted of the vital building blocks through short-sighted, profit-driven enterprise. Nature does not deplete itself, we do that. It’s time to start regenerating our soils and fixing the damage we continue to perpetuate. One way to do this is through the use of compost.
What is Compost?
Before we get into which microbes are present in compost we should first define what compost is. Compost is the process of taking waste products such as leaves, food scraps, grasses and the like and providing an environment that encourages decomposition. That decomposed matter becomes what we call compost.
Well-made compost will contain, for the most part, only beneficial bacteria or fungi. Think of the bacteria or fungal boxes in the soil food web picture above as having a dotted line down the middle: Half of the
species are “good guys” and help your plants grow, while the other half are “bad guys” that decompose plant tissues if growing on the plant surface. These “bad guys” bacteria and fungi are selected against in the
composting process, whether by high temperature, competition, inhibition or consumption by predators, or by passage through earthworm digestive systems, the result is the same.
Pathogens should be inactive and not detectable in well-made compost.
Organism biomass, diversity, and growth or activity can be enhanced by adding organisms, different kinds of foods, or nutrients to improve conditions for beneficial bacterial and fungal growth. Care needs to be taken to not add so much food resource that the growth of bacteria and fungi will consume oxygen to a detrimental level and allow the compost to become anaerobic or rancid.
The Stages of Composting
The Psychrophilic Stage
Psychrophiles are bacteria who are present in the beginning stages of composting. They prefer cold temperatures between 0 and 15 degrees but they are self limiting. What happens when you first build your compost pile is these guys start breaking the pile down and as they eat it up they generate heat. That heat reaction from their activity results in their death at approximately 20 degrees.
The Mesophilic Stage
As the heat begins to rise the Mesophile bacteria take over and continue the process. Again they are self limiting due to the heat generated by their activity. The mesophilic stage usually lasts just a few days before the heat becomes to high for these bacteria to continue to survive.
The Thermophilic Stage
The thermophilic stage begins with the high temperature created by the mesophilic stage and can last from 3 days to several months. The bacteria combined with oxygen and carbon from the materials in the compost pile to generate heat energy and carbon dioxide. Some of these are consumed by the bacteria in reproduction and the rest is given off as heat. Temperatures during this phase can reach in excess of 52 degrees.
The Curing Stage
The final stage of the composting process is called the curing, aging, or maturing stage, and it is a long and important one. Commercial composting professionals often want to make their compost as quickly as possible, usually sacrificing the compost’s curing time. One municipal compost operator remarked that if he could shorten his compost time to four months, he could make three batches of compost a year instead of only the two he was then making, thereby increasing his output by 50%. Municipal composters see truckloads of compost coming in to their facilities daily, and they want to make sure they don’t get inundated with organic material waiting to be composted. Therefore, they feel a need to move their material through the composting process as quickly as possible to make room for the new stuff coming in. Household composters don’t have that problem, although there seem to be plenty of backyard composters who are obsessed with making compost as quickly as possible. However, the curing, aging, or maturing of the compost is a critically important stage of the compost-making process. And, as in wine-making, an important element to figure into the equation is patience.
Immature compost can be harmful to plants. Uncured compost can produce phytotoxins (substances toxic to plants), can rob the soil of oxygen and nitrogen, and can contain high levels of organic acids. So relax, sit back, put your feet up, and let your compost reach full maturity before you even think about using it.
What will the compost do for my soil and plants?
According to Washington State University, using compost, in the soil, or as a component of your potting media is beneficial in many ways.
Compost contains a full spectrum of essential plant nutrients. You can test the nutrient levels in your compost and soil to find out what other supplements it may need for specific plants. See our tools page for a good soil test you can do yourself.
- Compost contains macro and micronutrients often absent in synthetic fertilizers.
- Compost releases nutrients slowly—over months or years, unlike synthetic fertilizers
- Compost enriched soil retains fertilizers better. Less fertilizer runs off to pollute waterways.
- Compost buffers the soil, neutralizing both acid & alkaline soils, bringing pH levels to the optimum range for nutrient availability to plants.
Compost helps bind clusters of soil particles, called aggregates, which provide good soil structure. Such soil is full of tiny air channels & pores that hold air, moisture and nutrients.
- Compost helps sandy soil retain water and nutrients.
- Compost loosens tightly bound particles in clay or silt soil so roots can spread, water drain & air penetrate.
- Compost alters soil structure, making it less likely to erode, and prevents soil spattering on plants—spreading disease.
- Compost can hold nutrients tight enough to prevent them from washing out, but loosely enough so plants can take them up as needed.
- Compost makes any soil easier to work.
Compost brings and feeds diverse life in the soil. These bacteria, fungi, insects, worms and more support healthy plant growth.
- Compost bacteria break down organics into plant available nutrients. Some bacteria convert nitrogen from the air into a plant available nutrient.
- Compost enriched soil have lots of beneficial insects, worms and other organisms that burrow through soil keeping it well aerated.
- Compost may suppress diseases and harmful pests that could overrun poor, lifeless soil.
Healthy soil is an important factor in protecting our waters. Compost increases soil’s ability to retain water & decreases runoff. Runoff pollutes water by carrying soil, fertilizers and pesticides to nearby streams.
- Compost encourages healthy root systems, which decrease runoff
- Compost can reduce or eliminate the use of synthetic fertilizers
- Compost can reduce chemical pesticides since it contains beneficial microorganisms that may protect plants from diseases and pests.
- Only a 5% increase in organic material quadruples soils water holding capacity.
How do I make compost?
There a number of ways to get started making your own compost. And that is the subject of another article however we will focus on Hot composting as it will provide you with the fastest turn around and the better quality compost.
Hot or Cold
Taken directly from Geoff Lawton
There are two main techniques for making home-made compost. Cold compost means gathering the materials together in a pile and leaving them to decompose naturally at their own rate. For this technique you still need to get the ratio of “green” to “brown” to be about even but there is less work involved as once you have mixed the materials together you simply need to leave it to its own devices. This technique is useful for a small kitchen compost pile which you can add kitchen waste to on a daily basis, balancing it out with carbon-rich “brown” to keep the ratio healthy. A slightly more complicated method is that of hot compost.
Some things to consider about this style of hot composting:
– It uses a lot of material right at the beginning so you need to have access to a large amount of organic matter all at once
– It also uses a fair amount of space – 1m x 1m x 1m is the usual recommended minimum – so is maybe not that practical if you are just planting up your back garden
Having taken these factors into consideration, if you feel the Berkeley Method (as it is known) is for you then read on!
How it works
The idea of hot compost is that you collect enough green and brown material (in the correct ratio) together that when you pile it up in a heap which you then aerate by turning it creates really great conditions for speedy decomposition to happen. This is due mainly to the presence of aerobic bacteria, which are the fastest digesters of organic matter. They are the reason for the need to create the right balance of carbon to nitrogen, and they also need a significant amount of oxygen to survive, which is why hot compost is turned to aerate it. The Berkeley Method has developed an exact time period when it’s best to do your aerating, which culminates in finished compost in just 18 days. Be sure to allow it cool and cure for a few days before using it.
YOU WILL NEED:
- A space to put the pile which is over 2m x 2m
- A mix of green and brown materials
- Lots of water ready to hand (if you have a hose that will reach the pile this is probably easiest)
- Tarpaulin or other material to cover the pile
Gather your materials and select the position for your pile. Remember you will need to turn it frequently so give yourself some space to work.
Using a fork or shovel begin layering your mix alternating between brown and green as you go. Wet it down and continue. If you would like to add some fresh manure do this every two to three layers.
When the compost begins to heat up (usually around day 4) you will need to begin turning it inside out every 2nd day until it has turned into deep rich coloured soil that smells like the forest floor after rain.
The process of turning is a lot of work and you need to be sure that there is enough moisture and oxygen to keep the bacteria happy. You should be able to squeeze just a drop or two out of the material, if not you may need to add more water. If you get more than a few drops from this test you will need to add more brown to absorb the water.
Making compost can be tricky but when you have worked out your method it is the best thing you can add to any soil.
How do I use the finished compost?
Using the finished compost can be as simple as spreading it on your garden beds and covering with mulch. Alternatively you may want to use it to start seedlings. If that’s the case we recommend the following mix to get your seeds off to a happy start and you will never buy potting mix again.
Seed Raising Mix
3-part sifted worm castings
2 parts copra or sifted compost
1-part river sand
Mix well. And then mix well again.
What ever you do in the garden always look for ways to compliment and assist nature to perform its natural functions. Work together and you will always have a lush beautiful space.
