I’m fascinated by compost. Out of all the organic, regenerative gardening techniques that I’ve learned, composting is the most beneficial and is directly tied to soil and soil health.
At first, it seems intimidating. There’s so much to learn. What are the greens and browns? How do you properly layer them? What are all these types of systems?
But at its most simple, composting is just mimicking nature… to our and our garden’s benefit.
Composting is the process of using biological methods to decay organic matter into nutrients that feed plants.
Finished compost is when the product of the compost method has become a rich brown or black (looking like soil) and there’s no plant material visible to the human eye. If the compost uses animal manure, then it’s when it no longer smells like manure but smells like earth. It’s at this stage that most compost is added to garden beds.
Technically, finished compost isn’t completely finished decomposing. (That’s why I use the word decay instead.) The compost is still pretty much made up of plant material (or animal manure), it’s just broken up so small we can’t see it. It’s not nutrients yet.
It needs to be added to healthy soil, where the microbiology, beneficial insects, and worms further break this plant material into the nutrients that plants can absorb through their roots.
There’s a lot of blog posts and books still in circulation that talk about humus and all its benefits.
For the past hundred years, botany mostly agreed that humus was the dark, rich blackness in soil that was the real benefit to plants, even though no one could define its structure (which, as the Garden Myths blog says, is suspect in this day and age, when we can use microscopes to define the molecular structure of just about everything).
As it turns out, what we thought of as humus was actually what happens when you severely bleach healthy soil: it becomes a black substance. It’s not actually in the soil beforehand.
What is important is organic matter. Organic matter is what improves soil and provides nutrition to grow big yields and healthy plants. You can see a lot of benefit in your soil by raising your organic matter to even 5%. And how do you do that? No-dig gardening practises, cover crops, and compost.
(If you only take one thing away from this, remember that we actually know very little about soil and how it actually works. We may be in for a lot of new discoveries! And as such, it’s best to mimic what nature already does, as nature knows best.)
Composting is just us humans speeding along and complicating what nature already does.
Imagine that you’re in a forest in autumn. The leaves turn colour and drop to cover the forest floor. Annual plants wither and die, leaving their stems and leaves there as well.
Throughout the year, trees topple and branches fall and animals drop manure or are eaten, leaving only bits. The snow comes, covering all that up. By spring, some of that has broken down and disappeared. By autumn again, more has disappeared and new leaves and detritus cover the ground.
If you brush away the covering, you’ll find rich, fertile ground teeming with life that was protected by all the detritus.
Beneath the surface, beneficial microbes, insects and worms are at work breaking down that organic matter into nutrients. This biology also has other benefits, like aerating the soil.
Composting is just taking advantage of this natural process using particular methods, then feeding that compost to our garden beds to provide protection and food for healthy soil.
Browns and Greens refer to the types of organic matter that you put into compost and each adds different nutrients.
Browns add carbon and include things like autumn leaves, paper, carbon, wood, and any plant matter that’s been dried. They’re more likely to be brown, thus the name.
Greens add nitrogen and include anything green or another colour, like vegetable and fruit kitchen scraps, fresh grass cuttings, and garden cuttings. Animal manure is considered a green (despite its brown colour) because it’s high in nitrogen.
Most compost methods require certain amounts of both, ideally layering 30 parts browns with 1 part greens (but will depend on the type of composting).
Too much nitrogen will burn off as ammonia during the composting process and burn your plants’ roots.
Browns will also help keep your compost well-aerated and help heat your pile so the compost finishes faster.
Ash from wood
Dried garden clippings/plant matter
Dried grass clippings
Fresh garden clippings
Fresh grass clippings
Manure (chicken, rabbit, cow, horse)
Seaweed and kelp
Straw and hay
Wood (logs, branches, woodchips)
You can compost any organic matter.
That being said, each type of composting has do’s and don’ts and handle different types of organic matter better or worse than other types.
For example, while you use hot composting for meat, fats, and dairy products, you’ll have a lot of problems, like pests. You can’t feed them to worms at all. Bokashi, on the other hand, is the most effective for composting meat. (We’ll get into this more when discussing different composting methods.)
Non-organic fruit and vegetable scraps should be rinsed off before being added to compost piles to remove pesticide residue.
Black walnut leaves and wood should NOT be composted as they contain a toxin that prevents most (but not all) plants from growing.
Wood chips can be composted (or leave them on as a mulch), but they require a lot of nitrogen to decay. This means that composting wood chips takes a lot of nitrogen out of your compost pile. But there are other methods, like the hugelkultur beds, that compost wood to fantastic effect.
Seaweed and kelp can also be composted. Seaweed has been used for centuries as a compost by laying it on top of garden beds as it contains 10 times the minerals of land-based plants. Rinse them in freshwater before use to prevent salt buildup or, if your area gets rain throughout the winter, apply them in the fall and allow the weather to do it for you.
Don’t use pet waste (cats and dogs) as a compost near any garden bed growing food as pet waste can spread pathogens that you don’t want on your food. Rabbit manure can be used safely. See the section on manure composting for more info.
If you have municipal compost pick-up, check their guidelines to see if they allow pet waste.
Terminology is tricky. Just because it’s marketed as compostable, doesn’t mean it degrades like other organic matter.
If they’re home-compost certified, meaning they break down in the same manner as food scraps, then you can throw them onto your compost pile.
Other bioplastics require industrial composting facilities to break down and should instead be put in your municipal compost bin (if you have one). If you add them to your compost pile, they won’t break down for a long, long time.
Let’s see how composting works through this video:
Very few gardeners have perfect soil. We make-do with too sandy soil where water runs through it faster than pouring water from a bottle or clay soil where even the lightest of rains sits for days.
But there’s one way that you can improve the soil of your garden without having to spend hundreds or thousands of dollars replacing the topsoil: compost.
(Yep, I know you’re really surprised at this conclusion, in an article about compost.)
The more organic matter soil has, the better it retains water. That means if you add compost to sandy soil, the organic matter will soak up the water and keep it there for longer.
Organic matter also increases aeration in the soil, which allows plant roots to spread and breathe and water to drain away. Add layers of compost onto your heavy clay soil and, over the years, you’ll build up a garden bed of perfect, loamy soil.
Once you apply synthetic fertilisers, rain or watering either washes it away (erosion) or sinks so deep in your soil that it’s unreachable to your plants. Either way, the effects don’t last long and you have to keep applying more.
Compost sits on your soil while the nutrients are being continually broken down and released for months (or even years) by the microbiology in the soil. Instead of continually fertilising, you may only need to compost once a year (more, if you’re turning over vegetable beds sooner). It won’t wash away and helps prevent erosion, as we found out above.
Compost protects and encourages the diversity of microbiology, insects and worms in your soil, which then go on to nurture your garden plants.
- All three break down the compost into usable nutrients for the plants.
- Beneficial insects and worms aerate the soil.
- Mycorrhizae (fungi) create a symbiotic relationship with your plants where they feed and help each other.
- Compost helps suppress pest and disease problems. Because your plants are on a healthy diet and supported by mycorrhizae, they grow up healthier and better able to fend off pests and disease. Pests prefer to prey on unhealthy plants unable to raise their biological defences against them.
You can use compost as a mulch by adding two to four inches on top of your garden bed. This mulch layer will:
- Make it harder for weeds to appear, as they have to germinate through extra inches of soil, which is no mean feat,
- Make it easier for you to pull the weeds that do appear, as soil with lots of organic matter is very soft,
- Protects your healthy soil microbiology from the sun and the cold, and
- Provides all the benefits and nutrition of compost.
The biggest cost of making your own compost is the initial investment in your infrastructure. Depending on your preferences and the type of composting you choose to do, this investment can be as little as $5 (or even free) or as much as hundreds of dollars.
But for most methods (bokashi not included), that’s where the costs end. You’re making compost out of things you’d otherwise throw away on yard waste day or in the garbage bin (or hopefully the compost bin, if your region has municipal composting services).
So compost is cheap, great for your garden, and reduces waste. Awesome.
Composting can be as easy or as complicated, as cheap or as expensive, as you want it to be. Whether you live in a one-bedroom apartment or on an acreage, there’s a composting method for you.
North American Indigenous peoples have been practising this form of composting for millennia. Instead of making the compost then adding it to your garden beds (requiring a ton of attention and labour), you make the compost in your garden bed.
In the autumn, simply dig a trench through the garden bed, throw in all your food scraps (the Indigenous people would also use fish heads and bones, which are high in nitrogen), then bury them under a layer of soil with a protective layer of mulch.
In the spring, you’ll find the soil has sunken where the trenches were, as the microbiology was busy over the winter. (You could also do this at other times of the year, although pests will be more of a problem.)
- Super easy and low maintenance, except for digging the trench.
- Retains more nitrogen during the composting process.
- Excellent for heavy-feeding annual plants.
- Pests (like raccoons, mice and rats) may dig up your trenches to get at the food scraps if they’re not buried deep enough (at least 12-18” deep). If you’re burying food scraps when you have plants in, then they may damage those plants to get to the scraps. (Don’t be too frustrated, though. They’re just trying to survive, and think that your trenches are their lucky lottery tickets.)
- Perennial garden beds or lawns, as you need to dig trenches and that will disturb your perennials.
- Yard scraps like leaves, straw, and other garden debris
- Kitchen scraps like leftover vegetables, apple cores, and fruit peels
- Meat, fish, dairy, cooked food (to avoid pests, bury them under at least 12-18” of soil)
Remember the forest description above? All the leaves come down to cover the forest ground, which will be broken down into nutrients.
You can do the same! Either leave fallen leaves on your garden bed to overwinter or, if you’re in an apartment, take a bin or garbage bag to your nearest park and scoop them up. Leave the bag in a closet for a year or two, and you’ll have leafmould.
- Easy and free to do if you’re in an apartment. Just go to your local park.
- No need to rake up leaves in the fall.
- You don’t have to balance out greens to browns.
- Doesn’t provide a source of nitrogen.
- Takes a long time, a year or two.
- If you have maple trees, you may wind up with a bunch of maple seedlings come spring. (I did.) On the other hand, I find it’s easier to pull up the maple seedlings than it is to rake up maple seeds.
- Dried leaves
This is the method that most people think about when they think of composting. You have a bin (or three) with air holes in the sides (or you can even just make a pile in the corner of your yard). To make the compost, you layer in your browns with some greens (30:1 ratio), and you turn it (mix everything up) with a shovel at least a few times.
Hot composting needs 3 things to work:
- Heat. The heat comes from the microbial activity in your compost. As they work, your pile will heat up. Organic-certified compost needs to reach temperatures of 131F or 55C. You’ll help this process by turning the compost (at least 5 times for organic standards) and feeding them 30:1 parts carbon to nitrogen.
- Moisture. The compost pile needs to be moist but not sopping. Too much and it’ll create anaerobic conditions. Too dry and the microbiology will suffer. This may mean that you’ll need to spray the pile with water or cover it from the rain. You will need a bin with drainage.
- Air. Getting air to the centre of the compost pile will speed up the process and will heat the pile hot enough to kill weed seeds and diseases. To make sure your compost gets enough air, you’ll need a bin with slats or chicken wire and you need to turn your compost regularly.
- Big Pile. Use a big pile in the corner of your yard. It won’t look great, but it works.
- Bin Composter. There are a few different designs, but all of them are basically a big box, either using slats on the sides or chicken wire. These are easy to DIY. You may want to get 2 or 3, so you can start your compost in one, turn it into the second while starting a new pile in the first, and then keep turning them into new bins.
- Tumbler Composter. These are the big cylinders on top of a rack that you turn by tumbling the cylinder. They’re a great option if you only have a small space or you’re unable to physically turn compost piles (although fuller tumblers are heavy and more difficult to turn). The downside is that you can’t make a lot of compost and rain may carry off a lot of the nutrients.
- Easy to make large volumes of compost.
- Can be fast to make compost if you tend it properly, between 1 – 2 months. If you take a laissez-faire approach, you can still make a large batch of compost once a year.
- When the compost heats up, it’ll kill off weed seeds and any diseased bacteria or fungi.
- Great for composting yard scraps, like grass clippings, fallen leaves, and garden clippings.
- You need to make at least a cubic yard of compost and you need a lot of yard scraps (browns), so it won’t work as well if you live in an apartment.
- If you forget about it and don’t turn it, it’ll turn into cold compost (which decays very slowly) or anaerobic (slow decay and stinks).
- You should avoid composting meat, fat, or dairy. You can compost other kitchen scraps, but if you have pests like raccoons, you’ll want to bury food scraps and use a bin that’s harder for animals to get into.
- You need to pay attention to the ratios of greens to browns.
- Yard scraps like leaves, grass clippings, straw, plant cuttings.
- If you get the pile hot enough, you can compost weeds.
- Fruit and vegetable scraps
- Fresh animal manure (see manure compost)
- Shredded newspaper
Cold composting is hot composting but taking longer and without the work. You build up a pile of yard and kitchen scraps, then just leave it to decay on its own. Cold composting takes a lot longer, from one to two years. You can also just keep adding to the compost pile as you go.
- Super-low maintenance and doesn’t require regular attention. All you do is add organic matter to the pile.
- Easy to DIY. All you need is a bin with aeration and drainage, like in hot composting.
- If you also do hot composting, you can keep the scraps in a cold composting pile until you’re ready and have enough materials for a new hot composting pile and it’ll already be a little bit decayed.
- Because it doesn’t heat up like hot composting, it won’t kill off weed seeds or disease pathogens. Avoid adding these to your pile!
- Takes a long time to become finished compost.
- Anything you can compost with hot composting
While hot composting is mainly about microbial action, vermicompost is all about the worms. Worms (mainly a breed called Red Wrigglers, or Eisenia fetida) eat carbon and kitchen scraps and poop out, well, worm manure. Vermicompost comes out at around 1-1-1 NPK and is a nice amendment for your garden, houseplants, or container garden.
Vermicompost bins come in three variations:
- Single bin. Using a single container (with appropriate air and drainage holes), the worms, food scraps, and vermicompost reside in one area. A really simple DIY if you’re just getting started, but it’s harder to harvest the vermicompost without taking the worms as well.
- Stacked Method. In this method, instead of a single container, you have 3 or more. The bottom layer is for any moisture to drain out. The next layers are where the worms live. Place the food in one layer, and when that’s mostly turned into compost, add a layer on top with fresh food. The worms migrate to where the food is and you can remove the previous layer to harvest the compost, then use it to add the next layer of food.
- Continuous Flow-Through. This is like the single bin, in which you have everything in one container, but it’s made out of cloth and allows you to open and close the bottom hole to harvest the compost. As you add food to the top, the worms migrate up while the finished vermicompost sits at the bottom ready to harvest.
Whatever method you use, you’ll start with a bed of carbon (like shredded newspaper) and a bit of something gritty like soil or coffee grinds. Moisten the carbon so it’s moist and not soaked. When worms are first introduced, they’ll need a few days to settle in.
- Simple and cheap to DIY a single bin or stacked method from plastic bins.
- Worms can be bought either from a local breeder or from a pet food store (where they’re sold live as bait or to feed pets).
- So long as you feed and care for your worms, they’ll breed and sustain their population so you won’t need to buy more.
- Since vermicompost can be done indoors, you can compost throughout the year, even when other compost methods slow down for the winter.
- Vermicompost can be done wherever you live, even apartment buildings.
- You don’t need to worry about ratios of greens to browns, although you do need to keep adding carbon.
- Kids (and the young at heart) love to watch the worms and it’s a great introduction for them into gardening and nature.
- If you or someone you live with is particularly squeamish about worms. Worms generally don’t want to escape your bin so long as you keep them fed.
- Once fruit flies breed in a vermicompost bin, it’s impossible to get rid of them. To cut down on the likelihood of this happening, freeze scraps to kill off any fruit flies before feeding the scraps to your worms and bury scraps under the surface.
- Fruit peels (but not citrus) and melon rinds (if not organic, rinse off pesticides before feeding them to the worms)
- Vegetable scraps
- Coffee grounds and used tea (check that the teabag is compostable)
- Grain products like bread, unsweetened cereal, plain pasta, cornmeal
- Carbon, like shredded paper, shredded cardboard, and dried leaves
- Meat, fats, and dairy products
- Animal feces
- Citrus fruit and rinds
- Onions and potatoes
A good rule of thumb is one pound of worms (approximately 1,000 worms) per one pound of food waste.
While all worms will process organic matter into worm castings, red wrigglers (Eisenia fetida) and red earthworms (Lumbricus rubellus) are ideal for vermicomposting:
- They prefer living in compost (rather than plain soil).
- They breed prolifically.
- They process organic matter quickly.
- They also prefer to live within the top 6” of the soil. (Nightcrawlers, what we usually think of as earthworms, prefer to live deeper, which while good for your garden beds is not ideal for vermicompost.)
Bokashi is technically a fermentation process rather than compost, but is still beneficial for your garden. You put your food scraps in a special bokashi bucket with bokashi bran, squeeze the air out of it, and allow it to ferment. After a few weeks, you bury it in your compost pile or in a trench in your garden beds to finish breaking down.
- Unlike other methods, you can compost meat, fat, and dairy products.
- The process is much quicker, completing in just 2 weeks. Once applied to compost or living soil, it breaks down much faster than finished compost.
- It’s a compact method that does not smell, so a good option for composting in an apartment or your kitchen.
- Doesn’t require turning or worrying about the ratio of greens and browns.
- The only regular attention it needs is to make sure you squeeze out all the air after adding new food scraps, adding bokashi bran, and regularly draining the liquid through the tap.
- No pest issues.
- Doesn’t smell.
- You can DIY the bucket using two 5-gallon plastic buckets, a lid, a drill, and a spigot (if you want to be to drain). You just need to make sure that the resulting bucket is air-tight!
- Bokashi isn’t finished compost. It must be buried under compost or living soil to finish. If you don’t have access to garden beds, regular compost, or garden containers large enough to support microbiology, you won’t be able to use the product.
- It’s expensive. It’s best to use two bokashi bins (as one will be tied up for ten days to ferment) and bokashi starter kits start at $50, including the bin and the bokashi bran. You can DIY the bin, but you need to keep buying bokashi bran to work.
- All food scraps, including cooked food, dairy, meat, grains, pasta, eggs, fruits and veggies
Manure compost uses the feces of livestock animals (herbivores) and has been used by farmers for hundreds of years. As animals digest organic matter, that organic matter is then broken down in their stomachs through anaerobic bacteria before being defecated.
Manure compost reintroduces bacteria into your soil and supplies both the primary nutrients (NPK: nitrogen, phosphorous, and potassium) and micronutrients.
Manure compost may come just as manure (also known as “pure”) or include bedding like straw or sawdust and animal urine (which can also be high in nitrogen).
- You’re reusing a byproduct of livestock farming and you can get it for free. Many horse stables will thank you for taking it away.
- Once manure compost is finished (also known as rotted manure), it doesn’t smell.
- You can easily buy bags of finished/rotted manure compost from garden stores and nurseries.
- Manure compost can be organic. (It depends on how the animals are cared for.)
- Reintroduces bacteria in your soil, increasing the diversity of microbiology and improving soil health.
- Supplies primary nutrients and micronutrients.
- Unfinished manure compost smells and needs to be composted using hot composting methods before use (unfinished manure may burn your crops from high nitrogen and high salt content). How long this takes depends on the animal. Horse manure takes the longest. Cow manure takes a year. Other manure, like chicken and rabbit, can be applied directly. Alternatively, if you’re applying to a field or large garden bed, you can apply unfinished manure in the autumn after harvest to be finished by spring (again, depending on the animal).
- If you are going to apply fresh manure on fruits and vegetables, you should do it at least 90 days before harvest, or 120 days if the vegetable comes into direct contact with the soil. Your intestines will thank you. (Finished manure is fine.)
- Improperly composted manure can have pathogens like E. coli and salmonella. When properly composted, internal temperatures reach 55C or 130F for two weeks or long which kills off these pathogens. Properly composted manure is considered safe by the CFIA and USDA regulatory bodies.
- Depending on the type of animal, improperly composted manure may have weed seeds. (Again, if composted properly, it reaches high enough temperatures to kill off weed seeds) Chicken manure generally contains no weed seeds.
- Don’t use manure from your household pets, like cats and dogs. Cat feces can contain viruses and bacteria harmful to humans.
- Livestock manure, like chicken, rabbit, cow, and horse
- Anything you can put into a hot composting pile
Avoid human and household pet feces.
Biodynamics is a form of organic farming that follows certain principles, ecological and esoteric, as set out by its founder Rudolf Steiner in 1924 in response to the rise of synthetic fertilisers and pesticides in farming. The farm is a whole, complete system that when healthy, is self-sustaining.
Biodynamic compost preparations are a key part of biodynamics as biodynamics seeks to keep nutrients within the farm, without needing to break in outside amendments. They are made from specific herbs, like yarrow, chamomile, stinging nettle, oak bark, dandelion, and valerian. These herbs are composted separately, then small amounts are added to the main manure/hot composting pile.
Maria Thun developed the Barrel Compost 502-507 for gardeners, using small amounts of fresh cow manure, basalt, and sun-dried eggshells as the base, then adding the herbal preparations.
- Brings a spiritual focus to gardening/farming, giving space for the gardener to remember why they’re growing their own food.
- If you know other biodynamics gardeners or farmers, you can trade preparations.
- More labour consuming than just using hot composting and most practices are best for farm-scale.
- Part of a larger spiritual philosophy and practices.
- Requires cow manure, or other livestock manure.
Biodynamic compost preparations are pretty specific about what ingredients go into it. Follow the recipes.
Hugelkultur takes trench composting to the next level. You’re essentially building a permanent no-dig bed on top of a massive deposit of organic matter, especially logs, branches, and other wood, that will take decades to fully decay. These beds can continue to supply nutrients for 20 years or longer.
- You set it up once and it’ll last you decades.
- With the addition of wood, beds continue to supply nutrients for up to 20 years, or even longer.
- Soil aeration increases over the long term as the wood breaks down.
- The logs and branches soak up rainwater to be stored during drier times.
- By building hugelkultur beds steeply (in a triangle, or like a Toblerone), you can grow vertically, maximising growing space and minimising the amount of time you’re bent over or kneeling on the ground.
- Hugelkultur beds require a ton of labour to set up. If you have a disability or health issues, you’ll definitely need help setting up. On the other hand, once they’re set up, they’re very low maintenance, unlike other composting methods.
- You need a source of wood logs and branches. Wood is a key feature to ensure it continues in the long-term.
- You need to be using in-ground garden beds, ideally ones that you will be gardening on for years to come. So give this one a miss if you’re container gardening, gardening in a community garden plot, or gardening on short-term rented land.
- Wood logs, branches, and any natural lumber that’s finished its days as furniture
- Any yard scraps
- Any kitchen scraps
- Seaweed and kelp
- Finished manure
- Straw and other mulch
- Back locust (won’t decay), black walnut (juglone toxin will prevent most vegetables from growing), old-growth redwood (won’t decay and can prevent seed germination)
- Wood that’s been pressure-treated or stained (due to harmful chemicals).
The best compost method for you depends on:
- What you want to compost (kitchen scraps, yard waste) and in what quantities
- How much space you have and how much access you have to living soil
If you have a lot of yard waste, go with hot or cold composting.
If you have garden beds but don’t want to regularly tend a compost pile, go with trench composting. If you want to set it up only once, go with hugelkultur.
If you have a lot of kitchen scraps, go with vermicompost or bokashi.
If you want to reuse animal manure or just buy compost, then go with manure compost.
You can always choose more than one method! For example, using a vermicompost bin indoors for your kitchen scraps and a hot compost pile for your yard waste.
Once your compost smells and feels loamy and is dark like rich earth, it’s ready to use.
- Apply 2 – 4 inches on top of your vegetable garden beds as a mulch and to replenish nutrients. Not only will you replenish your garden beds, but while the compost is being broken down into nutrients, it will also help prevent weeds and make it easier to weed.
- Mix DIY potting mix. When you need to buy a lot of potting mix, the cost starts to add up. You can cut down on the cost by mixing compost with other amendments.
- Revitalize old potting mix with compost to boost nutrients and aerate the potting mix. (Just be careful not to reuse soil that may have been infected with pathogens, disease, fungi, or pests.)
- Brew compost tea. While directly applying compost will always add more nutrients, the run-off from vermicompost or brewed compost tea can give plant containers added nutrients.
- Spread on a new or established lawn. Instead of synthetic fertilisers, sprinkle on compost. Alternatively, you can run the lawnmower over the autumn leaves until they’re in small pieces and they’ll decay into compost on the spot.
- Top dress around fruit trees. Like vegetable gardens, fruit trees can benefit from adding a layer of compost around their roots.
- Add compost to your perennials in the fall or early spring to give them an added boost.
- Don’t have a garden? Donate the compost to a nearby school, community program, or community garden.
Guide to composting for beginners:
The easiest composting methods for beginners are:
- Trench composting (if you have a garden bed)
- Cold composting (if you have space and yard scraps)
- Vermicompost (if you’re composting indoors)
- Bokashi (if you’re composting indoors with access to a garden bed)
If you’re using hot composting:
- Set your compost bin on bare earth. (This helps microbiology and worms get into your pile.)
- Lay down a few inches deep layer of twigs, straw and/or dried leaves. You may also want to add a layer of garden soil or finished compost to introduce more beneficial bacteria to your compost pile.
- Add brown and green organic matter in layers. Aim for a ratio of 30 browns (carbon) to 1 greens (nitrogen)
- Moisten the compost pile with a hose until it’s moist, not sopping. If it gets dry, hose it down again.
- Turn every few weeks with a pitchfork. In other words, mix the contents up every few weeks to help aerate the pile, increase the heat, and allow the organic matter to be decayed evenly.
- When the pile becomes a dark rich colour with a crumbly consistency and smells like earth, the compost is finished and ready to use.
How long compost takes to finish depends on the method you choose, how much labour and skill you put into it (turning, aerating, etc), the season, and the size of the organic matter you add to the compost pile. The smaller the pieces, the faster they break down.
Trench composting takes a season, generally from autumn to spring.
Leafmould indoors will take a year or two.
Hot composting can take as long as a year, or as short as two months, depending on the temperature you raise it to, the season, the size of the pile, and the aeration.
Vermicomposting can take from 1 – 3 months. Generally, when you start a new bin, it’ll take longer. Once the worms become established and proliferate, it’ll take as little as one month.
Bokashi can take as little as ten days before it’s added to the garden, then another 4 – 6 weeks as it fully decomposes.
Manure compost depends on the animal, with chicken and rabbit manure ready to apply as is, cow manure taking a year, and horse manure taking several.
You can compost non-organic food scraps (they are still food scraps), but ideally, rinse them off before you add them to your compost pile to remove any lingering pesticides and other synthetic chemicals.
Traditionally, gardeners and farmers have been taught that you have to work compost into the soil with back-breaking labour. But if you look at nature, you’ll find the composting matter is the top, protective layer. So save yourself the trouble. Apply new compost on top of your soil, and the microbiology will continue to break it down and water will bring the nutrients through the soil layers.
Finished compost is a great amendment to add more nutrients to your potting mix. You can even revitalise your spent potting mix by mixing it with a bit of compost or create your own.
But what about unfinished compost? Can you just add your kitchen scraps into your plant pots?
You can recreate some of the natural soil ecosystem when you’re using larger containers, at least 5 gallons. Smaller than that, and you’ll find it difficult to sustain the microbiology.
Compost may be nutrient-rich, but plants need other components of soil to live. The ideal soil only needs about 5% organic matter (compost). A little compost helps a lot. When revitalising potting mix, only use a 50-50 ratio. When spreading compost on top of garden beds, only go to a maximum of 4 inches.
You can tell when compost is ready (or finished) when it’s:
- A rich, dark brown colour
- Smells loamy (like walking in a forest) or smells like earth
- Feels like soil and has a crumbly texture.