First, here’s some great info-graphics for your reference that cover everything mentioned more in-depth below.
A comprehensive guide to complete composting from A-Z, especially for southern California’s dry climate.
First, an overview of compost chemistry and natural nitrogen & carbon cycles:
All organic matter is composed of large amounts of carbon (C) [or “BROWNS” in composting, woody material] and lesser amounts of nitrogen atoms (N) ]or “GREENS” or leafy material]. Carbon is of course abundant in the air (CO2) and helps create the rigid, structural nature of cellulose in wood and also is used in plant sugars (carbohydrates). Nitrogen helps create the proteins that use sugars to work in growing and repairing leaves and transporting nutrients. Plants need nitrogen to develop large, deep green leaves and strong stem growth. Although nitrogen is naturally present in soil, it’s not always there in amounts that are enough to sustain vigorous plant growth. This is because nitrogen is volatile and easily vaporizes into the atmosphere during soil-tilling or compost turning and when soil is left bare and exposed to the elements (not covered with mulch). Understanding how nitrogen works for plants can help guide your garden amendment choices.
“Ammonia and ammonium are other
forms in which nitrogen occurs. Ammonia
is a gas that becomes ammonium
when dissolved in water or when present
in soils or airborne particles. “
The balance of these two elements in composting is called the carbon-to-nitrogen ratio (C:N ratio). For optimal performance, the compost pile, or more specifically the composting micro-organisms, require the correct proportion or ratio of carbon and nitrogen in order to properly break down. Scientists have determined that the fastest way to produce rich, sweet-smelling compost is to maintain a C:N ratio somewhere around 25 to 30 parts carbon to 1 part nitrogen, or 25-30:1. If the C:N ratio is too high (excess carbon), decomposition slows down. If the C:N ratio is too low (excess nitrogen) you will end up with a stinky, anaerobic (without-oxygen) pile. For reference, straw or pine needs are already about 25 parts carbon to 1 part nitrogen, thus, a pile of pine needles will compost at a nearly optimal rate. Wood chips are about 300:1 carbon to nitrogen and grass/green leaves are about 15-20:1. Therefore, a pile of grass will become stinky and a pile of just wood chips will take forever to break down. This is not to say that anaerobic bacteria have no function in gardens; they just usually exist deep down in the soil and may or may not cause your plants to go into a funk if poured on top of the soil in large amounts.
Nitrogen in the atmosphere cannot be used directly by most organisms except for certain bacteria and archaea. These bacteria and archaea capable of assimilating and fixing atmospheric nitrogen (N 2) through natural means are referred to as diazotrophs.” 
Nitrogen & The Nitrogen cycles is important to understand in order to understand why most home gardeners feel like they don’t have a green thumb and/or have to rely on the nitrogen equivalent to “the pill” which is industrial chemical fertilizers to see plant growth. The way plants have obtained nitrogen for aeons without humans is through the natural Nitrogen cycles that exist. Air consists of 78 percent nitrogen in the form of N2 gas: two nitrogen atoms triple-bonded, requiring a large amount of energy to break apart the bond.
Not to worry – our plants don’t need to be industrial fertilizer junkies to have a garden that looks like it belongs on the front page of a magazine. Lightning strikes supply this energy during rainstorms and dissolve nitrogen into the accompanying rain! However, most nitrogen is processed into the soil and made available for plants by diazotrophs (free-living bacteria with nitrogenase) or rhizobia (bacteria that enter into symbiosis with certain plant roots). Nitrogen is added to the soil via nitrogen-fixing bacteria called Rhizobium naturally present in the root nodules of a variety of different plants loosely called “nitrogen-fixing plants”; i.e. the leguminous / pea (bean) family Fabaceae which includes alfalfa (Medicago sativa), 300+ different species of clover (Trifolium), beans, sweet peas, and more, etc.
Animals (including birds, mammals, reptiles, insects and humans!) introduce nitrogen into the soil through their waste. Dead and decaying organic matter allow nitrogen to be broken down into nitrites and nitrates by nitrifying bacteria in the soil. Our urine contains significant levels of nitrogen, as well as phosphorous and potassium (typically an N-P-K ratio around 11 – 1 – 2.5, similar to conventional store bought fertilizer)! As a basic premise, the urine must be mixed with carbon-rich materials in order for the nitrogen to become accessible to the plants.
30 parts carbon to 1 part nitrogen is the constant seen everywhere in nature required to perform metabolic functions at optimum efficiency: in the human body, in growing vegetable matter, and in compost. Since wood is 300-400 parts carbon to 1 part nitrogen, mixing them too deeply into soil can bind up nitrogen that plants need to grow because it is being used by microorganisms to break down the carbon-heavy matter. Nitrogen (coming from compost, bird droppings, rain, etc.) is not lost, rather it is “held up” until a certain point is reached and the majority of the carbon is composted, and then nitrogen levels will rebound and climb to more than existed prior to amending. In scientific terms, the nitrogen is a catalyst and so is not destroyed in the composting process.
“N-fixing plants are primary colonizers or pioneer plants, often growing in disturbed soils and paving the way for other, more advanced species to establish by pumping nitrogen into the soil, creating humus layers and micro-climates and more.”
How Do Plants Fix Nitrogen? Nitrogen fixing plants don’t pull nitrogen from the air on their own. They actually need help from a common bacteria called Rhizobium. The bacteria infects legume plants such as peas and beans and uses the plant to help it draw nitrogen from the air. The bacteria converts this nitrogen gas and then stores it in the roots of the plant. When the plant stores the nitrogen in the roots, it produces a lump on the root called a nitrogen nodule. This is harmless to the plant but very beneficial to your garden. How Nitrogen Nodules Raise Nitrogen in Soil When legumes and other nitrogen fixing plants and the bacteria work together to store the nitrogen, they are creating a green warehouse in your garden. While they are growing, they release very little nitrogen into the soil, but when they are done growing and they die, their decomposition release the stored nitrogen and increases the total nitrogen in soil. Their death makes nitrogen for plants available later on. How to Use Nitrogen Fixing Plants in Your Garden Nitrogen for plants is essential to your garden but can be difficult to add without chemical assistance, which is not desirable for some gardeners. This is when nitrogen fixing plants are useful. Try planting a winter cover crop of legumes, such as clover or winter peas. In the spring, you can simply till under the plants into your garden beds. As these plants decompose, they will raise total nitrogen in soil and will make available the nitrogen for plants that are unable to get nitrogen from the air. Your garden will grow greener and more lush thanks to plants that fix nitrogen and their beneficial symbiotic relationship with bacteria.
Compost is vital for the garden. It provides nutrients, gives good texture, fixes poor soil, retains water, buffers pH, and provides a home for billions and trillions of beneficial microbes and fungi. Compost is a bit of an art, and not something you can rush. The best soils on earth have taken hundreds of thousands of years to be what they are today, so we must keep that in mind when we worry about five or six months to make a great compost. In this guide we are going to touch on every aspect of compost from what is compost, types of compost, how to make it, and lastly benefits of compost in the garden.
What is Compost? – Compost is any organic matter that is broken down into its simplest form. Finished compost is called humus (and no that is not what you eat, that is called hummus) pronounced HEW-MUS. It is black or dark brown, and almost all the original inputs are unidentifiable. The pH of compost is neutral or right around 7.0 making it a perfect buffer for acidic or alkaline soils. It also holds FIFTY to TWO HUNDRED times more water than the best clays (in its own weight). Humus
Types of Compost
o Cold Compost – This is a pile that is left for years to weather without ever being flipped or added to. The pile is essentially “cold” because it does not heat up like its closest relative; the HOT compost pile.
Pros: The benefits to a cold compost is that the lack of extreme heat allows for a more diverse range of beneficial bacteria, insects, and fungi to colonize the pile. It is by far the most natural route to composting.
Cons: The downside to cold composting is since there is no flipping or adding, or stimulating, the compost may take 1-3 years to fully break down.
o Hot Compost – Hot composting is the process of piling material up into a large pile, and actively wetting and flipping the pile to keep specific bacteria highly active. This high level of activity is what generated heat, and can reach up to 180 degrees! A hot compost pile is recognized by the steam that is emitted from the center when flipped. Pros: Hot composting is one of the fastest forms of composting. Due to the level of heat many weed seeds, diseases, and harmful fungal spores are killed off.
Cons: Due to the high levels of heat many species of beneficial bacteria, worms, and other beneficial insects will die in this environment. In rare cases compost piles have caught on fire.
o Vermicomposting – This type of compost is made from the process of digestion from worms. Vermicomposting is the act of putting worms into an enclosed container with food, and their natural function is to digest food making for convenient and very effortless compost.
Pros: The nutrient quality of vermicompost is nearly triple that of regular compost. The digestion process also incorporates billions of beneficial microbes into the compost which interact with plant roots and help to create a healthy environment for life. Vermicomposting is also very easy, they require very little care and the food has to be added only once every week or so.
Cons: Worms need to be fed in order to stay alive. Also worm bins need to have moisture and be indoors because of the many animals that feed on worms.
o Bokashi Compost – This type of composting that involves anaerobic bacteria breaking down food scraps in an enclosed bucket. Bokashi composting utilizes beneficial bacteria much like the bacteria found in our stomachs and soil. The bacteria belong primarily to three strains: yeasts, (Saccharomyces spp.), bacteria that produce lactic acids (Lactobacillus spp.), and (phototrophic) purple non-sulfur bacteria (Rhodopseudomonas spp.). These, or bacteria like them, are the active organisms in yogurt and in silage. Pros: Bokashi composting is easy, and does not require the maintenance that a hot compost pile does. The fact that it is beneficial bacteria in an anaerobic environment, many things that would normally never be safe to compost are. This allows for about 90% of the food we would normally have to throw away to actually be composted. Things like; meats, eggs, and greasy foods.
Cons: One of the downsides of bokashi composting is that the starter for the compost must be purchased on a very regular basis. Making your own bokashi compost starter is very dangerous and can breed E. Coli bacteria if done wrong. Also, the process can smell more foul than the other methods of composting, and since it requires plastic buckets, this is another expense to you.
How to Make Hot Compost – Hot compost as we discussed earlier in this article is the process of piling up organic matter to be broken down by extremely active bacteria. In this section we will also cover the ever so confusing “Carbon to Nitrogen Ratio”. The steps to getting to the point of heat is crucial, here is how.
Step 1 – Gather 1 part brown material (e.g. Shredded cardboard, mulched leaves,
dead grass clippings) this is a carbon source. Carbon makes up every living thing
and is the building block for life. You need that and 1 part green material (e.g.
green grass, plant matter, fruit and vegetable scraps) this is your nitrogen source.
Nitrogen feeds bacteria, and its only purpose is to act as a catalyst in the compost
pile to stimulate the bacteria.
Complete Guide on Composting 4
NOTE: “green” material DOES NOT have to be green in color. This adds
confusion – green material is anything that has a high nitrogen
makeup. Green plant material like grass is in fact green in color but also high in
nitrogen. An example of something not green but high in nitrogen is coffee
grounds, animal manures, and yes…. Urine. While they are not green they are
VERY high in nitrogen. So why the brown and green thing? Really that is just an
easy way to remember what is required for the compost pile to have the ability to
heat up enough to be considered “hot”. Really as gardeners what we are worried
about is equal parts carbon to equal parts nitrogen.
1 PART BROWN AND 1 PART GREEN
Step 2 – Take the brown and green ingredients and pile them up. This is where it
becomes crucial to the effectiveness of the compost pile. A small pile say 1 foot
wide by 1 foot tall will NEVER heat up because there is not enough organic matter
to feed the microbes and create a core hot enough. The pile must be AT LEAST 3
feet wide by 3 feet tall. Also, the pile cannot be something like 5 feet wide and 1
foot tall because that again will NEVER heat up to the point where hot composting
Complete Guide on Composting 5
Step 3 – Moisture is critical to help microbes survive. They need water just like
you and I do, and they need lots of it to keep going. After piling the ingredients
together, you want to wet the compost pile down. Soaking the pile is not necessary,
but you do want to feel a noticeable wet texture in the center of the pile, almost
that of a damp sponge.
Step 4 – Flipping a compost pile is vital to ensuring
everything composts at the same rate, and also provides
food for the microbes that they have not come in
contact with. It is important to flip the outside in, that
way the more composted material is on the outside. A
pitchfork also comes in handy when it comes time to
flip. When you flip the compost pile, you will know if
things are working when you see steam even on a warm
day. This is because a hot compost pile can reach
temperatures of up to 180 degrees! Flipping should be
done once every week or so as soon as the pile decreases by roughly a 1/3 its size.
Step 5 – After about 3-5 months your compost will cool down and begin to look
very black. No matter how much water or flipping you do the pile just won’t heat
up. This means that the pile is done and the compost is finished. It is important to
cover the compost pile with a tarp, this will ensure that the quality of compost will
remain until it is ready to be used on the garden.
Benefits of compost in the garden
Complete Guide on Composting 6
o Improving Soil Texture – Compost helps to break up clay soil by
preventing clay particles to bind to eachother. This improves aeration in
heavy clay soil. It also helps in sandy soil to give something for water
and nutrients to hold onto.
o pH Buffer – Compost has a pH of roughly 7.0. This makes for a great
way to fix acidic soil or alkaline soil.
o Retains the Perfect Amount of Moisture – Compost is very porous, this
acts as a sponge to soak up water, as well as hold onto it. As we
discussed this can help in sandy soil because of a lack in water retention.
This can also help in areas where droughts are common. Compost will
hold onto water, and allow plants to take what they need when they need
o Re-mineralize The Soil – Compost has many minerals essential for plant
life. Compost has an NPK of around 2-1-1 making for an extremely
gentile fertilizer that will never burn plants. Compost also has essential
minerals like calcium, iron, magnesium, and many other smaller amounts
of trace minerals. This well balanced feeding will give your plants
exactly what they need.
o Good Porosity – Porosity is the measure of how porous something is.
We already discussed how the porous nature of compost is good for
retaining water, it also retains nutrients. Nutrients flow out of the soil in a
process called leaching. Leached nutrients can be soaked up by
compost’s sponge like properties and held on to for future use.
o Home for Beneficial Microbes & Fungi – As we just discussed in
regards to porosity, this has to do with it as well. The sponge like nature
of compost has TONS of surface area. This surface area allows for
microbes and fungi to colonize. Having good amounts of beneficial fungi
Complete Guide on Composting 7
and bacteria in your soil is very good since research has shown a direct
correlation between plant health and soil microbial counts.
Conclusion – I hope this guide has helped you in some way to make better
compost, and to incorporate compost into your garden. Composting is something
as gardeners we must start doing in order to give back to the soil what we took out.
Modern agroculture is based on the premise of keep taking but give nothing back.
We cannot sustain that path or we will be looking at our own dry, cracked, and
barren land we once used to grow crops on. Always remember.
“The nation that destroys its soil, destroys itself” – Franklin D. Roosevelt
Thank you for reading!
~End Document~Convert kitchen, yard and garden waste into soil-nourishing organic matter with our backyard tested composting bins and supplies. Decreasing household waste and building your soil has never been so easy!
Many home gardeners prefer to put up with a slight odor and keep some excess nitrogen in the pile, just to make sure there is always enough around to keep the pile “cooking!” Learn more about building a compost pile here.
THANKS TO MIGARDENER.COM
Soil “Clay has super fine particles that cling together and prohibit water and nutrient movement, while sand has course particles which allow water and nutrients to leach too rapidly.
There actually is one more classification called silt which has particles sized between clay and sand.
Loam is a mixture of these sizes and is the favorite of most plants because it is usually richer in nutrients and humus and will retain water while allowing the excess to drain away.
There are other soil types in between these as well, sandy loam, clay loam, silty clay, etc.
Clay, sand and silt are definitions of textures. The following picture show respective sizes of these 3 different particles;”
Ventura County, a Mediterranean or dry summer subtropical climate, is the climate typical of areas in the Mediterranean Basin, Southern California and more, and is usually characterized by mild rainy winters and dry, warm to hot summers allowing us to grow many tropical fruits and vegetables that the rest of the United States can’t grow like bananas, papayas, dragon fruit, passion fruit, kiwis, pomegranties, and all kinds of amazing fruits you may have never heard of like Sapote, Jabuticaba, Strawberry Trees, etc. etc! Obviously, we’ve been thirsty for rainy winters for a good amount of time now, but converting your property into a food forest still helps heal the planet by 1. reducing the amount of water needed on your property to 1/2 that of a normal lawn (save on your own water bill), 2. growing your food in a way that uses less water than conventional agriculture via proper planting, mulching & deep perennial root systems saves more planetary fresh water in the long run!, and 3. reducing the amount of gas, energy & time used transporting your food and yourself to and from the store (do your part in reducing your carbon footprint, atmospheric co2 levels, and other green house gases!).
The subtropics are geographic and climate zones located roughly between the tropics at latitude 23.5° (the Tropic of Cancer and Tropic of Capricorn) and temperate zones (normally referring to latitudes 35–66.5°) north and south of the Equator.
Subtropical climates are often characterized by warm to hot summers and cool to mild winters with infrequent frost. Most subtropical climates fall into two basic types – humid subtropical, where rainfall is often concentrated in the warmest months (for example Brisbane, Queensland or Jacksonville, Florida) and dry summer (or Mediterranean), where seasonal rainfall is concentrated in the cooler months (for example Naples, Italy or Los Angeles, California).
Subtropical climates can occur at high elevations within the tropics, such as in the southern end of the Mexican Plateau and in Vietnam and Taiwan. Six climate classifications use the term to help define the various temperature and precipitation regimes for the planet Earth.
A great portion of the world’s deserts are located within the subtropics, due to the development of the subtropical ridge. Within savanna regimes in the subtropics, a wet season is seen annually during the summer, which is when most of the yearly rainfall falls. Within Mediterranean climate regimes, the wet season occurs during the winter. Areas bordering warm oceans are prone to locally heavy rainfall from tropical cyclones, which can contribute a significant percentage of the annual rainfall. Plants such as palms, citrus, mango, pistachio, lychee, and avocado are grown within the subtropics.
In geography, temperate or tepid climates or latitudes of Earth lie between the tropics and the polar regions. These regions generally have more variety in temperature over the course of the year and more distinct changes between seasons compared with tropical climates, where such variations are often small.
The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arctic Circle (approximately 66.5° north latitude). The south temperate zone extends from the Tropic of Capricorn (approximately 23.5° south latitude) to the Antarctic Circle (at approximately 66.5° south latitude).”
Sources / References:
- “NITROGEN IN THE NATION’S RAIN” – http://nadp.slh.wisc.edu/lib/brochures/nitrogen.pdf