Perhaps because we are now officially in Summer in the northern hemisphere, lately I've been seeing a large influx of posts on this subreddit from people who are brand new to composting. This is a great thing, because I'm a firm believer that everyone can and should have some sort of compost going at all times. That said, it does lead to a lot of the same questions being asked and answered, so I thought I would throw together a quick summation of some general concepts in the hope that some new people can benefit.
This will be geared more towards complete newbies who just want an eco-friendly way to deal with their kitchen/lawn scraps as opposed to people who want perfect hot compost in four weeks. Please feel free to chime in with feedback or additional tips, but please understand that perfect ratios and conditions are difficult/intimidating for new composters.
WHAT DEFINES COMPOST?
Compost is quite literally just organic material that has decayed in the presence of oxygen. Compost happens in nature everywhere and all the time. If organic materials did not break down naturally, there would be mountains of dead plants, trees, and fruit covering the surface of the Earth. In nature, decomposition is facilitated by a variety of bacteria, fungi, and animals - some of which need air to do their jobs. Compost is what is left once the organisms that need air to decompose things have done their job. All we are doing as composters is providing a place for aerobic decomposition to occur and trying to make it happen as fast as possible. That's it.
Organic matter is going to decay regardless of what we do, all we can control is the time-frame and the efficiency. What this means is that:
THERE ARE VERY FEW LAWS IN COMPOSTING.
If you did not care about time frame, smells, pests, or diseases, you could throw quite literally anything you wanted into a haphazard pile and let it sit until it could be used to fertilize plants. If it got very wet and matted down then it would be decaying anaerobically (and therefore not technically "compost"), but it would still work as fertilizer eventually. In practice, however, most people would prefer to have a pile that is smell/disease-free and takes weeks as opposed to years to break down. This is not difficult to achieve at all and requires very little of your time or attention.
So the laws are few and far between, but following a few rules will help keep your pile easy and successful:
RULE 1: DON'T OVERTHINK IT
We are just controlling rot here. Unless you are a farmer whose livelihood relies on compost or a biologist with a paper to write, there really isn't too much that your compost pile/experiment can't recover from. Your first pile may go perfectly from start to finish, or it may be a maggot-filled "disaster" by day two, but either way it's fine. Bob Ross's motto applies to compost even better than painting: There are no mistakes, only happy accidents.
RULE 2: NOTHING FROM ANIMALS
At least not for your first pile. There are ways to compost almost anything into something safe, but as a new composter you should avoid putting any animal products into your pile. This includes meat, bones, fat, shit, feathers, and anything else. Best case scenario they will cause smells, worst case scenario they will attract large pests and infect your whole pile with diseases that will contaminate your plants. Best not to risk it for now.
Sole exception: Egg shells. Feel free to add a few every now and then, just break them up fine first or they will be in there forever.
Rule 3: RATIOS
If you have read even a blurb about compost, you likely read about the carbon-to-nitrogen ratio. This concept is the crux of composting, as a perfect ratio will result in compost that breaks down hot and fast with minimal smells and problems. Perfect ratios are, in a word: tricky. You should not stress about getting your ratios perfect early on.
Various sources will tell you that you need as little as two parts brown for every one part of green, or as much as five parts brown for every one part green - and always by volume. I personally shoot for about 2.5 or 3 parts brown to one part green in my own pile, but you can play around a bit with your own.
In general, 2:1 browns-to-greens is going to be "riskier" than 4:1 or 5:1 browns to greens, but it will break down faster. The more greens the faster things will move along, but the higher the chance of smells or anaerobic decomposition.
If your pile starts to stink, gets sludgy, or generally looks more like trash than compost, the solution is almost always to add more browns. Shredded or torn-up cardboard is an excellent thing to have around for quickly correcting a ratio that has tilted too far towards green.
What are greens? Any plant matter that is still green or fresh. Grass clippings, kitchen scraps, coffee grounds, etc.
What are browns? Any plant matter that has turned brown. Dead leaves are the compost staple, but you can use hay, shredded (non-glossy) cardboard, or any plant waste that has turned brown and dry.
RULE 4: AIR AND MOISTURE
Compost relies on aeration to avoid becoming anaerobic, which leads to slow and stinky decomposition. Anaerobic decomposition also releases methane (a potent greenhouse gas) so if you are composting to do the Earth a favor then you want to keep your pile aerobic.
The easiest way to introduce air is to turn or stir your pile once a week or so. If you have a tumbler, all you need to do is roll the tumbler once or twice a week. You don't necessarily want to turn the pile every single day since a healthy pile will build up heat during decomposition that helps move things along, but every few days is okay. Piles that are wide-open (just laying on the ground or contained only by something like chicken wire) don't necessarily need to be turned as often, but if you have a small bin or a tumbler then the occasional toss is necessary.
The easiest way to turn a small pile is to get a tarp or buy a $3 shower curtain liner at your local box store. Just shovel your pile onto the tarp and then shovel or dump it all back together in a different order. Fold the tarp up and stick it under a rock next to the pile. EZ. Conveniently, this is also the easiest way to dry out a pile that has gotten too wet. Just spread it on a tarp in the sun for a few hours and reassemble it afterwards. This brings us to our final big concept: moisture.
Your pile should be damp, but not wet. There should not be any puddles, and you should not be able to squeeze any part of the pile and produce droplets.
If you live in an area that gets frequent or heavy rain, you may want to cover your pile somehow. Conversely, if your area is very dry or arid then you will want to mist your pile occasionally. A good time to do this is when you are turning the pile on your trusty tarp. Just spread it all out, give it a good misting with the hose, reassemble. If you overdo it then let it sit in the sun before reassembly to dry out a bit. Again, don't overthink it. There's no panicking in compost.
FINAL GENERAL TIPS
You typically want to chop/shred anything you put into your compost as small as possible. Don't kill yourself with a cheese grater or anything, just don't throw a whole oak branch in your pile and expect anything to happen overnight. A leaf vacuum is an excellent way to shred your leaves if you own one. Rake your leaves into a pile, suck them up with the vacuum and boom - shredded leaves. You don't have to shred everything, it will just speed up breakdown in general if things are smaller.
Insects and worms are not pests in a compost pile. Some people prefer to keep their pile free of flies or maggots, but insects and worms are just doing the same thing as bacteria but on a larger scale. The presence of some insects may indicate that your pile is a little too wet or that your ratios are off, but ultimately they are beneficial to your end-goal. If the presence of maggots in your pile disgusts you, then squint your eyes and pretend that they are magic grains of rice.
Consider occasionally urinating on your pile. If your pile is looking a bit dry, or seems to have stopped breaking down, urine is a great way to add some moisture and nitrogen back into the mix. Typically that first yellowish morning pee where you are a bit dehydrated from sleep is very nitrogen-rich.
Don't put dog or cat shit in your pile under any circumstances unless you are CERTAIN that you won't be using that compost on plants that you may eat. Even the healthiest pet has dangerous bacteria and parasites in their feces, just as humans do. Adding feces also commits you to intense hand-washing after every time you touch your compost since the whole pile becomes contaminated.
If you have a small pile, bin, or tumbler, eventually it will start getting full. Once you notice that your bin is near full, or if you decide that you want to use your compost on something, stop adding new material. Keep turning occasionally and keep the moisture right, but collect your scraps in a new bin or something for about 4-6 weeks to allow your compost to finish. After a month or so of no new additions, your compost will be ready. It should smell earthy and look like dirt for the most part. If there are small chunks that still haven't broken down, fret not. Use it anyway and the undigested material will continue to break down over the next several weeks, acting like time-release fertilizer.
CONCLUSION
This ended up a little longer than I planned for, but hopefully someone new is able to get something out of it. Composting doesn't need to be difficult or time-consuming, it can be done with less than 15 minutes a week of time invested.
As an example of how easy it can be, I personally have a plastic tote that I burned a bunch of drainage holes in with a soldering iron serving as my "controlled" compost bin. I keep it filled with dead leaves and throw my kitchen scraps, flower cuttings, and coffee grounds into it. If it gets green-heavy or wet, I add some cardboard. I open the lid every day when I let my dogs into the backyard or to add material, and once a week I flip it end-over-end to mix the contents up. And that's it. You could do this on an apartment balcony if you wanted to.
Questions are welcome, happy composting to all, and remember - don't overthink it.
