Composting 101: A Beginner’s Guide to Composting in Your Garden

Composting is a natural extension of your garden routine. This process reduces waste and feeds your garden, is sustainable long term, helps the environment, and isn’t even that much additional work! Learning how to compost will change the way you work in your garden and interact with your surrounding ecosystem. 

How Composting Works

Compost is the process of decomposition that results in a nutrient dense amendment that you can apply to your garden beds. Think about it - your garden, and your kitchen for that matter, is already producing waste. Instead of throwing this waste in the trash, let’s use it and cycle it back into the environment! 

The decomposition is the result of billions of tiny organisms that utilize the two main chemical components of organic matter (carbon - the brown, dry waste that comes from your garden and nitrogen - the green, fresh waste that comes from your garden) in their life processes. They consume carbon for energy and nitrogen for growth and reproduction. The matter works its way down the food chain of organisms in a pile, one organisms’ waste becoming the next one’s food - so on and so forth. What cannot be digested is left as decomposed organic matter (compost).  Therefore, the key to good compost is providing the right environment for these organisms. Decomposition rates are directly proportional to the number of organisms present. The better the conditions, the more organisms, the more compost you get to put back into your garden. 

What does my compost need?

Compost needs just a few basic ingredients to really get cooking (literally). The right combination of these ingredients will result in a happy ecosystem of decomposition. It may take some time to find the right balance for your environment, but once you do, there are often minimal issues. 

Your compost needs…

• Carbon-rich materials - think dry, brown, and brittle like dried leaves, straw, or wood chips

• Nitrogen-rich materials - think fresh and green such as grass clippings, animal manure, and kitchen scraps

• Air and moisture are also necessary components for these organisms. 

Any compost pile will decompose eventually but it can take a very long time and produce horrible smells if not done correctly by combining all of the necessary elements. For home composters, the process can be a bit of an art! Start with equal parts by volume of carbon- and nitrogen-rich materials in your pile and see how it performs. Try layering the piles like a lasagna, switching between nitrogen-rich and carbon-rich materials, layering any assistive additives throughout. Too much dry, brown materials can cause a pile to decompose very slowly, while too much fresh green materials causes rotting, making the pile stink and attracting pests.

As we mentioned, the organisms that break down organic material need oxygen to live and reproduce. They feed on surfaces that are in contact with the air. Therefore, the smaller the pieces of organic matter, the more surface area that is exposed, the faster the organisms can decompose them. This is the difference between whole sticks or wood chips or even chipped leaves versus whole leaves. Materials that are added to the compost pile should generally be broken up into smaller pieces. 

How to Compost

Typically when we’re talking about composting we’re referring to a compost pile. Mounding up organic matter into a pile increases the materials ability to absorb, store, and release heat. More heat can support a larger population of organisms. There is a balancing act here too, however. Too small of a pile won’t be able to create the necessary amount of heat to support the lives of these organisms, but too big of a pile will result in a limited amount of oxygen reaching the middle of the pile - which is also an important part of the composting process. We recommend starting with a 3x3x3 food mound - this is a great and reasonable size for folks just getting a handle on this process.

Oxygen and Compost

Organic materials can decompose without oxygen but the process can take a really long time. One of the benefits of building a pile with materials that vary in size, texture, and coarseness is that the piles are filled with air pockets. Turning the pile speeds up the process by introducing air and stimulating microbial activity. If you never turn the pile and don’t find another way to aerate, then the oxygen is slowly used up. Bacteria that function in little to no oxygen take over and the decomposition process takes a lot longer. These bacteria that can function without oxygen are known as anaerobic organisms. Bacteria that do need oxygen are known as aerobic organisms. With compost piles, we prefer the process of decomposition to be handled by aerobic organisms. 

Methods of Compost Aeration

Turning your pile is the most common method of aeration used by home gardeners. Composters can be purchased that are designed to turn easily - typically you’ll see them as a barrel on a stand that “turns” easily with the use of a handle. These are great tools. But - composting can be done with few to no tools as well - so long as you have a handy shovel! We like this multi-bin compost system for home gardeners, ensuring that there is a regular supply of compost ready to amend your beds!

Moisture and Compost

Moisture is another essential part of the compost system. Too little water will slow decomposition and too much water will fill up air pockets, ultimately also slowing decomposition. We recommend you shoot for a 40 to 60% moisture content in your pile. Luckily - there’s an easy way to tell if your pile is at this level of water content. Take a handful of compost in your hand and squeeze it into a ball. Water should not seep out between your fingers. This is how you know the compost isn’t too wet. When you open your hand, the compost ball should stay intact in your palm and not crumble. This is how you know your compost isn’t too dry. 

Troubleshooting Overly Wet or Dry Compost

If you’re finding that your compost is too wet - fear not! Mix in dry bulking materials like woodchips, shredded cardboard or newspaper, straw, or other similar materials. These things will take in moisture, and the mixing will aerate, allowing for a better moisture content! 

Piles that are too dry should be watered. The best way to do this is to turn your pile and water with a hose as you’re digging through it. This will result in an evenly moist pile rather than a pile that is just really wet on top. 

The Process of Decomposition

When it comes to getting the hang of composting - understanding the processes happening in the background is really going to help you not only understand what’s happening in your pile but also help you trouble shoot. If you know generally where the ecosystem stands - you’ll be able to address any surprises more effectively. There are three steps to decomposition; degradation, conversion, and curing. All materials will do this but the speed in which it happens depends on the environment. 

Degradation

During this phase, organic materials are broken down and microorganisms consume nutrients in the materials. As they feed and multiply they create heat and release water and carbon dioxide. These microorganisms then become dormant and/or are consumed by other microorganisms as the temperature rises. 

Conversion

During conversion, humus (pronounced hyoo-mus, meaning decomposed organic matter)  is built up. Temperatures in the pile drop and microorganisms that work at lower temperatures take over and complete the process. The resulting compost is considered “fresh,” also sometimes referred to as “raw.” This is the compost that can nitrogen-burn plants and raises soil acidity. It’s best to wait for the next phase before applying this compost to your garden beds.

Curing 

During the curing process, microbial activity subsides. Earthworms return and as the compost sits it continues to decay and calms down. The length it takes to cure depends on what the compost is made of. Once the compost stops heating up after being turned, you can let it sit for about four weeks to cure. The longer it sits, the more nitrogen it loses, which is actually a good thing because it will be gentler on your plants.

Organisms

So what’s happening in your compost pile during these stages? No decomposition takes place without the actual organisms doing the work. These include various bacterias, fungi, and actinomycetes. The larger invertebrates include earthworms, centipedes, mites, nematodes, rove beetles, springtails, the list could go on. Knowing who to look out for - at least those which you can see, will help you intuit the health of your compost pile.

Bacteria

Many bacteria live on the surface of organic matter and are dormant until the right conditions are created. Once this happens, they can begin their jobs in the decomposition process. There are three main types of bacteria:

Psychrophiles

This bacteria prefers cool temperatures as low as 28 degrees. They do most of the winter work that happens in a compost pile. Materials don’t decompose below that temperature, but even on colder days, the middle of the pile can stay that hot. As they digest carbon, they generate heat.

Mesophiles

When the temperature in the pile reaches about 60-70 degrees, these guys take over. If you were to start a compost pile mid-summer, this bacteria would start the process. Mesophiles are responsible for most of the decomposition in a home compost pile. They are active up to 100 degrees. Raising the temperature any higher than 100 degrees usually isn’t necessary unless you’re trying to generate higher temperatures to kill diseases or weed seeds. Under particularly optimum conditions, the mesophiles create so much heat that they raise the temperature above 100 degrees.

Thermophiles 

After the pile reaches 100 degrees, this bacteria will work to raise the temperature even higher! The optimum temperature is between 130-140 degrees for a high heat compost system but sometimes this bacteria can raise the temperature too much. If the temperature gets above 160 degrees you risk killing the beneficial organisms including the thermophiles and end up with sterile compost. If your compost is getting too hot, you can cool the pile by turning it. While not strictly necessary, a compost thermometer can assist with getting an understanding of where your compost is at in the decomposition process and potentially help avoid the worst case described here. 

Fungi

Fungi in the pile breaks down cellulose and lignin- the fibrous, woody parts of organic materials after the bacteria gets started on the digestible parts. 

Larger Invertebrates

Various insects, mites, and worms also live in the compost pile. They feed on larger materials, breaking them down into smaller pieces, making them easier for microorganisms to process. They also help to transport microorganisms around and throughout the pile as they’re able to travel. Their poop (or excrement, if you prefer) represents the decomposition that has happened within their bodies. As temperatures rise in the middle of the pile, these invertebrates move to the outer edges, returning to the center as microbial activity subsides and temperatures drop. 

Seasonal Composting Tips

Composting is a year round garden task - but it looks a little different depending on the season! As the year progresses, take care to follow these tips to ensure your compost is performing and getting what it needs at every time of year. 

Spring

Happy spring! Whether you’re just getting your compost pile started or maintaining your long-time pile, this is an exciting time of year. For established piles, it’s time to aerate and turn your pile! As the temperatures warm up, so does biological activity in your pile. Add oxygen into the mix to heat things up (literally). Keep in mind to balance your greens and brown - nitrogen and carbon - this time of year. Spring clean up can offer plenty of carbons - like leaf mulch, but throw in kitchen scraps and grass clippings as well. 

Summer

This is peak composting time! Bacteria are most active and decomposition is accelerated. Keep your pile turned regularly. Keep an eye on moisture in summer as the high heat can dry piles out. And - if your pile is somewhat established - this is a great time to harvest compost from previous seasons to apply to your garden beds. 

Fall

Fall produces quite a bit of organic matter to add to your compost pile but keep in mind to keep things balanced. Mature compost should be left to cure - as it’ll be perfect by spring. 

Winter

While decomposition slows down in winter, you can continue to add to your compost pile. There may be a limited amount of carbon based additives while you’ll probably have an abundance of kitchen scraps. Try to keep your additions even by including wood chips or sawdust in the mix - even in deep winter. We’d recommend covering your pile with a tarp through the winter to prevent an excess buildup of moisture that may cause problems in spring. 

The Final Product

The size of the pile is usually one half to a quarter of the original size. Dark, moist, and earthy, it’s made up largely of microbial cells, exoskeletons, partially decomposed fibrous or woody matter and perhaps some inorganic particles like rocks or glass. Knowing the nutrient content of your compost is not super important and is difficult to calculate. It’ll pretty much always differ from pile to pile. In general, though, compost produced under higher temperatures tends to have somewhat higher nitrogen content than when produced at lower temperatures. You can also add amendments such as rock powders to piles to manipulate the phosphorus and potassium content. 

Common Composting Mistakes

When learning how to compost, you’ll likely run into more than one issue here or there. Luckily, most everything has a fairly simple solution! 

Designing your Compost Pile as Just One Pile

Compost “pile” is a bit of a misnomer, because as we’ve established, compost is best prepared with multiple piles. One pile that you’re continuously adding to will never result in fully composted organic matter, because there’s always more to compost! As the decomposition process progresses, take care to start a new pile (or use the aforementioned bin method) that will mature later, creating a constant succession of this amazing garden amendment. 

Incorrect Ingredient Balance of Nitrogen and Carbon

This is probably the most common composting mistake - depending on your circumstance - you’re likely to end up with an overabundance of either dry materials or fresh kitchen scraps and grass clippings. This lack of balance can result in an unproductive compost pile (too many dry materials) or a slow, stinky, wet compost pile (too much fresh material). It is essential to balance these ingredients for a productive compost set up. 

Not Paying Attention to What You’re Adding to Your Compost

You may hear people complain about their compost piles attracting pests - this can be due to a few different reasons. Typically pests will bother your pile if there is too much nitrogen which causes rotting, which attracts pests, but also adding the wrong materials like meat, seafood, oil, or dairy. These smells are highly attractive to pests. Further, adding diseased plants, weeds that have gone to seed, or straw or grass clippings that have been sprayed with herbicides will hurt your garden when you apply your compost to your beds. Disease can spread through compost, as can weed seeds, and compost with herbicides will stunt the growth of your crops! 

Composting Tips

We mentioned earlier that home composting is a bit of an art. And it can take a few tries and some experimenting to get it right! There’s nothing wrong with getting a little help and there are a few things that might benefit your pile of decomposing deliciousness.

Alfalfa Meal

This is a common plant fertilizer that helps to increase organic matter in the soil. It also works to encourage beneficial microbes and earthworms to break down nutrients. This is exactly what we’re looking for in a compost helper. In compost piles, this additive decomposes rapidly which creates heat and helps the rest of your compost to decompose, making more nutrients available to your plants. 

All Purpose Fertilizer

This is not only a great fertilizer but this mixture of feather meal, fish meal, alfalfa meal, kelp meal, and blood meal also acts as a compost activator. The additions of these ingredients will add organic matter and a wide range of nutrients to your compost pile and help heat this up. 

Blood Meal

Blood meal is very high in nitrogen which makes it a great addition to piles that struggle to balance between greens and browns - and tend to end up with mostly browns. The high nitrogen content will help boost the productivity and biological activity of your compost pile.

Biochar

Biochar most notably increases aeration in compost - kind of acting how perlite would in a seed starting mix - and this ultimately helps to speed up the composting process. Some research suggests that biochar in the right quantities can speed up the composting process by as much as 20% - pretty impressive! It also reduces odors and reduces nutrient leaching from compost. It’s pretty much a harm-free additive and absolutely worth throwing in the mix. 

Garden Lime

Compost that is very raw or fresh is really high in nitrogen which can burn seedlings and harm plants. This high nitrogen content translates to compost being quite acidic. Garden lime helps to calm soil acidity and also adds calcium to soils. Can be helpful when turned into “raw” compost piles in autumn that are in the curing stage to be used in the Spring. 

How Do I Use It?

Compost has so many different incredible uses. It acts as a homemade fertilizer, adds organic matter into the soil, helps to break up clay soils over time and builds healthy soil ecosystems. Lay your cured compost on your garden beds in autumn or early spring, a few weeks before planting. You could even use a broadfork or tiller to turn it into the soil. You can even mix it into a potting mix to give your indoor plants a little nutrient boost! 

Compost Tea

Compost tea is a homemade liquid fertilizer. Fill a compost tea bag or other burlap sack with finished compost. Place your bag in a bucket and add water. Let your compost tea stew for a week or so, swirling around once or twice a day. Once complete, dilute your tea 1:1 with water and spray on your plants! This makes a great foliar or root fertilizer. Compost teas are particularly good at preventing and controlling fungal leaf spot diseases. 

How to Get Started

Ready to start composting? Let’s get going! Start your pile now so that next year’s growing season has an abundance of this waste-free amendment to add to your garden. 

1. Choose a Location

When deciding where to put your compost pile - make sure it’s out of the way of where you might be spending time, but not too far from the garden that it won’t get used. While composting is cool, and if done right should be fairly stench-free, we wouldn’t recommend putting it right next to your patio. Pick a spot where you’ll remember to maintain it! Sun and shade will both work but just remember full sun will cause your compost to dry out faster while shade will cause it to stay wet longer.

2. Decide on Your Materials

Are you building loose piles? Are you using bins? Are you using a compost spinner? Think about what materials you might need to design your compost system and collect them. Pallets are typically easy to find (and often free) but three trash bins will also work great and keep your system contained. 

3. Assemble Your Organic Matter

Collect your carbon-based and nitrogen-based organic materials! Layer them like you would a lasagna so they can start doing the work. Make sure to not add too much of one or the other. You want your contributions to be fairly equal. 

4. Experiment with a Maintenance Schedule That Works for You

Composting is low maintenance in general but keeping an eye on it, ensuring it stays evenly moist without becoming too wet or too dry, and turning it regularly will result in high quality compost that is easily handled by the average home gardener. Find what schedule of checking on your pile and maintaining it works for you! 

5. Let Nature Do the Work

Sit back and watch your compost magic happen! Over time you’ll have a regular supply of high quality amendments to add to your garden beds every time you’re ready to plant. Get started today! Your future self will thank you. 

	Article Written by: Hannah Gibbons
	About the Author: Hannah Gibbons, an employee at Sow True Seed since 2020, has nearly a decade of experience in the agricultural industry. Their passion for environmental education and regenerative agriculture has been the cornerstone of their work, aimed at making gardening accessible to all.