Home Composting in 3 Steps
Term Definitions:
Turning: Physically stirring, moving, or flipping your compost (in order to improve aeration). Think of it like stirring a pot
Compost Pile: A pile of organic material, completely open to the weather or only partially contained. The traditional method of composting
Compost Bin: An enclosed bin that is stationary
Compost Tumbler: A enclosed bin that rotates (tumbles) in order to make turning compost easier
Greens: Fresh plant material to put in your compost (think green leaves, or fresh kitchen scraps) - for more info see below
Browns: High carbon material to put in your compost (think brown cardboard, brown leaves, brown paper bags) - for more info see below
Composting can seem intimidating. There are a million articles about what kind of composting, how to do it, how to achieve hot composting. How you are probably doing composting wrong….
Composting is not complicated. All you are doing is concentrating and accelerating the natural breakdown of organic material in a controlled fashion.
1 Key Rule and 3 Steps:
Key rule: Never put animal products (or anything that has touched an animal product, like being cooked in butter) into your compost. It will smell and attract vermin.
3 Steps:
1. STORE: Buy a bucket for your kitchen to store food scraps, fill with scraps. Set aside cardboard or paper bags
Preferably a bucket with a lid.
Air holes are optional, but if the bucket has them, I find the carbon filter inserts actually do work
Paper towel tubes, grocery store paper bags, non-color printed cardboard boxes (basically things you would have recycled)
I use this bucket, highly recommend:
2. FILL: Buy a compost tumbler for outside your house and dump the bucket in when full. Add one bucket worth of Browns (same bucket), and 1/3(ish) bucket of water (same bucket), for each bucket of Greens
Tumblers are good as they seal (keep out vermin), you can fill as you go, are very easy to turn, and are more attractive than a pile.
For the bucket I used above, its volume equals either one .5 Sqft cardboard box, or 2-3 brown paper supermarket bags. Paper towel / toilet paper cardboard tubes also are great. Tear everything up when adding
No need to be exact on the water, just add enough water that the browns look slightly soggy after turning the tumbler. I usually just add the greens and browns, turn it twice, and see if the browns are soggy. If not I add the 1/3 bucket of water
I use this tumbler. It works fine, but has not held up (I have had to keep the panels together using zipties).
See the buying guide Coming Soon! for tumblers that look like they may work (though I haven’t tried them)
3. TURN: Turn tumbler (3x rotations) at least once a week
Most tumblers already have fairly good airflow, this helps kick it up
If there are issues (like the tumbler smells) see below:
It’s done when material looks like gritty dirt (likely 2 months from the last time you added material)
That’s it.
More Info and Common Questions:
What's this Green / Brown thing and how much should I put in?
People use the term "Greens" to refer to anything high in nitrogen going into your compost. Think of this as any fresh plant product (ie. Green leaves). Coffee grounds also count as Greens (and are one of the best things for compost IMO)
"Browns" are anything high in carbon (ie. Cardboard, brown leaves, or wood mulch, etc). These act as the structure and bulk of the compost/soil you are helping create.
You will find as many different ratios of Green to Brown as there are articles on this topic. I have found that a 50/50 ish ratio works pretty well, remembering that cardboard is denser than you think.
My rule of thumb is for one bucket of food scraps, I put in one torn up small (.5 sqft) cardboard box or equivalent paper product (ie 2 - 3 grocery store brown paper bags).
How do you tell if your ratio is off?
Smell and temperature. Your compost should never smell like rot. If it smells like rot, you need to add more Browns. Add the amount of Browns I describe above, turn the tumbler and wait a day or two. If it still smells, repeat until it no longer smells.
If your compost is "working" aka there is active biological breakdown occurring, it should be reliably giving off heat. Stick you hand into the tumbler (you can hold it in above the compost). Does it feel like there is heat radiating off the compost? If so, you have enough Greens. If not (or if you're not sure if its giving off heat), you need to add more Greens.
You can also use a thermometer to check the temperature, but if the ambient air temp is above 80F, it can be hard to see if there’s a temperature differential caused by activity. (see below)
How do I know its working?
Temperature is the classic test. If it is between 80F - 100F (or higher) consistently, it means there is biological activity. You can buy a long compost probe (I use the one below), but frankly, if you stick your hand into the tumbler, and you can feel heat radiating off of it, that’s good enough.
(side note: with most tumblers you won’t feel heat outside the compartment regardless of state)
Do I need to add water?
Yes, but less than you think. Kitchen scraps tend to be fairly wet. If you are adding used coffee ground/ paper filters, the Greens going in will already be very moist. The easier test is do the browns look soggy? (its why I like cardboard, you can tell immediately if its soggy or not). If they don’t look soggy, add half a compost bucket worth of water and turn the tumbler. Give it a minute, and then look again. Repeat as necessary.
How much is too much water?
Water should never be dripping out of your tumbler (except immediately after you add some). The rule of thumb is "a damp paper towel, where if you squeeze only one drop of water comes out) level of moisture. Unless you stick your hard into it (which I do, but I understand that grosses a lot of people out) this is hard to approximate. My advice would simply use common sense. If things look "wet", there is too much moisture. Two ways to fix this: You can add another helping of browns and turn; Or you can wait and just skip adding water the next time you add greens / browns.
What is this hot compost thing I should be trying to achieve?
Hot composting is when the biological activity produces enough heat for your compost to reach 140 - 160 F, which then turns the compost pile into (effectively) a bioreactor. You will not achieve this with a tumbler.
There is a minimum size of pile to achieve this. Consensus seems to be around 2 - 3 cubic yards of material if you mix in freshly cut grass. The smallest I have been able to achieve it with is a 2 cubic yard pile, and that was with 1 cubic yard of freshly cut grass, daily turning, and the reaction only lasted about a week before it burned through the "fuel". I had to then finish it at more normal temperatures.
However, your compost should be warmer than the surrounding air, or if the air is over 80F then consistently in the 80F - 100F range (with some variation). If its below that, its running low on fuel. Add more Greens and turn. (also see answer above)
Ultimately, hot composting vs “cold” composting doesn’t matter for you at a home scale. Don’t worry about it
How long will this take?
It depends (I know…). If the weather outside is warm (above 55f), for a normal 1 cubic yard tumbler, probably 2 months. (if you fill it all at once). If you are filling it as you go (which I do) until the tumbler is full, I assume 2 months in the summer from the last moment I added material. If finish filling In the spring / fall, I would assume 3 months (so long as the air temp stays above 55f).
If the air temp drops below 55f, that’s when biological activity starts to shut down. If you finish adding material late in the fall, it’s not going to finish until the next spring / summer. In a tumbler, that’s fine. The compost will freeze over the winter, and will start back up after the spring defrost. You can help it along in the spring by adding a handful or two of dirt from your garden (so long as its pesticide free) or a compost starter. This will act as a probiotic.
Can I compost Dog / Cat / Pet waste?
No. Remember the key rule. This also goes for human waste (we are just animals).
I have a bunch of leftover compost i’m not using yet, what do I do with it?
I buy cheap plastic storage tubs from Walmart/Home Depot etc and fill them up, then stick the compost in the back of my garage. The goal is to keep it out of the rain, so the nutrients don’t get washed out of it. The same goes for piles sitting outside over the winter, covering them with a tarp works fairly well.
There are recommendations that you “age” your finished compost, which is effectively storing it in plastic storage bins and sticking them in a temperate (55 - 70F) garage / shed/ basement for 3 - 6 months. There is some literature regarding how the microbiome changes as things continue to breakdown to plants benefit.
I have not seen any robust science saying that this is advantageous over using un-aged compost, however, I also can’t see that it would hurt it (so long as it’s not having water running through it, sucking nutrients out). By default this is what I do over the winter with unused compost / as I build up compost over the season. Again, plants love both un-aged and aged compost, i’ll run an experiment to see if I can see a difference.
Should I compost my plants at the end of the season?
No. Without achieving reliable hot compost (140+ F for a multi-week period), you will be transmitting diseases from the plants to the compost, and then back into your garden soil.
If you live in an area that does organic recycling, bag it up in brown paper bags (like the yard waste bags you can get at Home Depot / Lowes), and give it to them. Commercial level organic recycling / composting performs hot composting, which will kill anything in the soil.
If you don’t, give them to the trash guys in the same above. (at least it will break down better in a landfill in paper than a plastic trash bag)
The one exception to organic recycling rules are tomatoes / other nightshades. Because of tomato blight, you are supposed to either Burn your tomato plants at the end of the season, or Seal them in plastic trash bags and dispose. This is good practice for any plants you feel are diseased regardless of species.
Tomato blight is dangerous enough to agriculture that you are technically supposed to report any suspected cases to your State Agriculture department. Most home gardeners do not.
What is worm composting (vermiculture)? Should I do that? Is it better?
Vermiculture (composting with earthworms) is using captive worms in a contained environment to quickly break down your organic material. Its is much quicker than tumblers (worms digest their body weight in material per day), and reliably introduces earthworm casing’s into your compost (a great source of complex nutrients), but you are now taking care of worms. They like any animal, need constant attention, care, and tending.
If you are interested / good with small animal care (its like having a fish tank that makes compost), by all means take it on. There are many well reviewed options (i’ve listed some below).
However, it is a dedicated, nearly daily, time commitment, and requires a fair amount of research to get the environment right for your worms. For someone that’s already busy, I don’t recommend it.
I want to have a compost pile, how do I do that?
See my compost pile article. Coming Soon!
Can I compost colored or ink covered cardboard? Can I compost color printed paper?
Maybe. The problem with ink (particularly colored ink) is that it was made with heavy metals in the past. This has been banned in the US, but it’s hard to say where packaging was made these days. I avoid composting anything that is heavily printed or color printed (unless it explicitly says made with Soy based ink, tends to be with hyper environmentally friendly brand’s packaging).
Obviously, do not compost any treated cardboard (has a plasticy feel / sheen, like a pizza box) or treated / high sheen paper (magazines fall into this category, same with many newspaper inserts). Some would say not to compost used printer paper as well. I have not seen the science either way, but I err on the side of caution, so do not.