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What is Composting?
Black gold? Plant superfood? Organic fertilizer? Planet saver? Compost is many things to many people.
For our purposes, compost is what happens when various decomposing organisms – bacteria, fungi, and other microbial critters – take organic waste streams and turn them into a nutrient-rich soil amendment.
Compost is rich in organic matter, nutrients, and beneficial microbes. Yes, plants need probiotics too!
This combination provides plants with much to almost all – depending on the quality of the compost – they need to produce nutrient-rich foods, save water, additional soil, and sunlight. You will need to ensure plants have the remaining three!
Note that compost is not a “more is always better” soil amendment. Too much compost can actually harm your plants and over time, even your soil by causing nutrient imbalances. So make sure you are doing an annual soil test on your growing space!
How to Compost
Compost is a lot like people. It needs four things to survive – food, water, air, and shelter! It appreciates a little love as well, but that isn’t crucial. Let’s look at each one of these separately.
Food: What to Compost
The microbial critters that transform waste into compost need two types of food, greens, and browns. Generally, you want more browns than greens, in fact, about 3-5 times as much brown material!
You can add as much composting raw material as quickly and as often as you want. Just make sure that as you add food waste and greens, you also add ample browns to keep smells and other issues in check.
Examples of green material would be leftover bits from chopping vegetables and yard clippings. Examples of browns would be coffee grounds and wood chips.
While neither a green or a brown, eggshells are also excellent to compost. They add needed calcium.
What to NOT Compost
While you can theoretically compost anything, trying to in an urban environment isn’t always the smartest idea.
Meats, soups, stews, and other smelly, fatty, and liquidity stuff is hard to compost at a small scale, dramatically increasing the likelihood that your pile will create bad smells and attract unwanted pests.
This may thus result in upset family members or neighbors, neither of which is generally in your favor.
Also, if you are using your compost for vegetable growing, cat and dog poop or other types of manure are not appropriate to toss into your compost pile.
Bacteria don’t just need food, they need water as well. But like plants, both too much and too little water can cause problems for your compost. Too much can lead to smelly liquids draining from the pile (these liquids are sometimes called leachate, and in some areas you can actually be fined for having uncovered compost for this reason!) Too little means stuff won’t break down and your pile will just sit there, a dry dead lump of built-up detritus waiting for water or rain to help it along and for the bacteria and other decomposers to get back to work.
To avoid too much rain, I suggest making a compost bin that is easily covered. You can use different things for the cover – a tarp, plywood, or my favorite, a piece of sheet metal. A slanted roof is better than a flat surface since this allows water to naturally shed off to the side that makes the most sense.
The process of breaking down stuff requires a great deal of oxygen for all our little bacterial and fungal friends. Without sufficient air, a pile may go anaerobic – a decomposition process that uses different bacteria that also create some strong smells among other unwanted effects.
To avoid this, some people will turn their piles. I try to avoid extra chores whenever possible, so instead, I suggest you build a pile so that it naturally gets sufficient airflow. The design at the end of the article will give some options for you to consider!
Yes, compost piles need shelter. Too much heat, too much cold, too much rain, too much sun, too much wind can all cause a compost pile to break down more slowly than it should. Excess rain is one of the biggest issues a pile faces. Don’t place your pile under the side of a structure where lots of rain or water will fall on it! Even if you follow my advice and give it a roof, you don’t want your pile located in a swampy or otherwise soaked spot! This can lead to bad smells and other issues.
One reason compost piles fail over winter is that they freeze. This is partly because many are too small (a note on that below!). It is also because they are placed in a cold, shady spot that gets wind. A frozen compost pile is just a pile – no composting is taking place! So instead of having nice compost ready come spring, you have a frozen block of partially broken down material that won’t be ready until late Spring or early Summer. Not ideal at all!
Does Compost need Starter?
Also, note what compost piles don’t need. They don’t need a composting starter. You can spend money on a compost starter, but they are pretty unnecessary unless you happen to live in a very polluted area.
Compost bins don’t need additives and amendments – save those for applying directly to your soil after you know you need them because of a soil test. All compost needs is you to provide the 4 things listed above!
Mother Nature knows what to do. She’s been decomposing stuff for a long time. Just give her the basics and the rest will magically happen all by itself.
Go Big or Go Home
One reason composting doesn’t work for people is that they don’t produce enough material to make a sufficiently large enough pile. You need a big enough amount of material to create the kind of mass that makes compost magic take place. Here are a few solutions if you have trouble producing enough compostable material to make your pile happy.
Band together – Get a few other families involved with providing you with scraps and other compostable materials. They can be family, friends, neighbors, people from church, or strangers you shakedown on the street.
Commercial Food Waste – Commercial composting companies like EcoScraps collect food waste from restaurants, grocery stores, and produce wholesalers. No reason you can’t get some of that for your compost bin as well. Just be sure the food waste is high quality. For example, waste composted from some restaurants apparently kills plants within 12 hours.
Coffee shops – An average small coffee shop produces 5 gallons (about 45-60 lbs!) of coffee grounds PER DAY! At one point, I was picking up over 2000 pounds of grounds a week from us a handful of shops in the city. A large city produces tens of thousands of pounds of coffee grounds each year. Sadly, most go to the landfill.
Coffee grounds are one of the BEST, lowest cost, and CLEANEST ways to build beautiful garden soil. They also make a great compost addition.
So if you need more bulk for your compost pile, call around to a few shops and see if they need someone to take some of their grounds on occasion. Skip fast food places that serve cheaper coffee and seek grounds from Starbucks and independent cafes that serve high-quality brew.
The Best Compost
Plan to stop adding greens and browns to your compost bin about 30 days before you need it. You will know your compost is ready to use from the smell and the texture.
Compost that is ready has a dark color with a good consistency in your hands with no remaining visible signs of food or other scraps. It has a clean, earthy smell that is very pleasant!
If you wish to continue to add raw materials after the 30-day cutoff, it is best to keep two compost bins side by side. This way, while one compost bin finishes, the other can continue to be filled.
How Much Compost to Use in the Garden
- How rich the compost is.
- The condition of your soil.
- Intensity of cultivation.
As mentioned earlier, an annual soil test is very important to help determine how much compost you will need in any given year.
DIY Compost Bin (simple, inexpensive)
My favorite small scale compost maker uses five wooden pallets and takes under thirty minutes to make. It looks nice and is easy to manage.
Four of the pallets are left whole, while one is cut in half to provide an easy to access front edge and to also make the make a slanted roof to protect the pile from rain. You can make the roof from wood, metal, or some other material. To attach the roof, we use rope, metal wire, or leftover baling twine.
The spot should be relatively level for where you locate the pallets and pile. Also, make sure that the spot in winter isn’t shady or windswept. Try to choose a spot that will get lots of winter sun and is somewhat sheltered from wind. This is especially important the farther north you are.
Once the pallets are assembled, it is best to layer a bunch of branches, sticks or similar material on the bottom, about 4-6 inches deep. This provides additional space for your compost pile to draw in air and helps reduce the need for turning. Another option for providing more airflow is to use pieces of scrap PVC pipe with ¼ inch holes drilled in them buried in the pile. The pipe should extend beyond the sides of the pile and they will draw in air to the very center of the pile, keeping things moving along nicely. Scrap PVC is easy to find and a very good way to reuse something that is rarely recycled!
Below is a picture of this DIY compost bin without the cover. It is courtesy of Rachel James.
Keeping Animals Out of Your Compost Bin
Compost can sometimes create issues with unwanted critters seeking a free meal. With the above design, putting hardware cloth underneath and all around the sides if one way to keep them out. For the lid, you will need to make sure you can either lock it closed or weight it down to keep them out.
If you have a great deal of rat pressure, you may need to set traps, get a few cats or use other measures to reduce their population. I have seen them chew through metal if there are too many in an area, and they are aggressively searching for food!
Another option to keep critters away is to purchase or build a barrel tumbler composter. They keep pests out better than the DIY compost bin above. There are many available for a good price online such as this one.
There are many free plans online to build your own composting bin or tumbler as well. Note that this type of bin design will compost faster than the design I give above, but also require a bit more work along the way.
Composting in the City
I often suggest for city folk to keep a large trash can full of wood chips or similar high carbon, brown bedding material next to their compost pile (with the lid on!).
This lets you easily add more browns anytime your pile could use more material to capture smells.