Step 4 - Composting
Composting for Beginners
Composting is a ratio and a habit. Get both right and the rest genuinely takes care of itself.
Janet H. - the hands-on owner behind Janet Media Group.
Published - last updated
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Two to three parts browns to one part greens by volume, kept about as damp as a wrung-out sponge, turned when you remember. That is composting. Everything else is refinement.
The ratio, explained
Decomposing organisms need both carbon for energy and nitrogen for protein. Extension and EPA guidance converge on roughly two to three parts brown material to one part green by volume, which works out to something like a 25 to 30 to 1 carbon-to-nitrogen ratio by element.
You do not need to measure any of this. What you need is the habit of adding a handful of dry material every time you add a bucket of wet material.
| Browns (carbon) | Greens (nitrogen) |
|---|---|
| Dry fallen leaves | Fruit and vegetable scraps |
| Cardboard and paper, torn up | Fresh grass clippings |
| Straw | Coffee grounds and tea leaves |
| Sawdust from untreated wood | Soft garden prunings and green leaves |
| Small twigs and woody prunings | Spent plants at the end of the season |
| Used potting soil | Crushed eggshells |
Starting a pile
- 1
Start with a coarse base
Four to six inches of twigs, woody prunings or coarse browns at the bottom. It absorbs excess liquid and lets air get in underneath.
- 2
Layer greens and browns
Roughly one part greens to two or three parts browns by volume. Do not obsess over the measurement -- a handful of browns per bucket of scraps is close enough.
- 3
Bury fresh scraps
Push new material into the middle rather than leaving it on top. It breaks down faster, and it does not attract flies.
- 4
Check the moisture
Squeeze a handful: it should feel like a wrung-out sponge and release a drop or two, not run. Add water if it is dusty, add browns if it is soggy.
- 5
Turn it when you remember
Every couple of weeks is ideal. Turning adds oxygen and mixes wet with dry, and it is the single biggest difference between compost in two months and compost in a year.
What to leave out
Meat, fish, dairy, oils and cooked food -- home piles do not get hot enough, for long enough, to handle them, and they attract rodents. Cat and dog waste, for pathogen reasons. Diseased plant material, and weeds that have gone to seed, unless your pile genuinely heats, which most home piles do not.
The full list is in what to put in a compost bin.
Troubleshooting
| Symptom | Cause | Fix |
|---|---|---|
| Smells sour or like ammonia | Too many greens, not enough air | Add plenty of browns and turn it thoroughly |
| Nothing is happening | Too dry, too many browns, or too small | Add greens and water, and turn it |
| Flies around the bin | Fresh scraps sitting on the surface | Bury scraps and cover with browns |
| Soggy and matted | Too wet, often grass clippings in thick layers | Add dry browns, turn, cover if rain is the cause |
| Rodent activity | Meat, dairy or cooked food, or an open bin | Remove those inputs; consider an enclosed tumbler |
Knowing when it is done
Finished compost is dark, crumbly and smells of earth. You should not be able to identify what went into it beyond the odd twig or eggshell fragment. If it still smells sour, or you can recognize food in it, it needs longer -- and unfinished compost temporarily locks up nitrogen when it goes into a bed, which shows up as pale, stalled plants.
Then it goes onto the bed: 1 to 2 inches across the surface each spring. See the best compost for raised beds for how much and when.
What to buy
The products that fit the advice above, chosen by the process on our how we choose page. We have not hands-on tested them; specifications are the manufacturers’ own.
Quick picks
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 |  Top pickFCMP Outdoor IM4000 Tumbling ComposterDual chamber, roughly 37 gal total | Most backyards | 9.1 | Check price on Amazon |
| 2 |  OXO Good Grips Easy-Clean Compost BinSmall lidded pail, smooth-walled for rinsing | The counter caddy | 8.3 | Check price on Amazon |
| 3 |  GEOBIN Expandable Compost BinExpands to roughly 216 gal, 36 in tall | Leaves and yard waste | 8.7 | Check price on Amazon |
#ad We may earn a commission - prices are shown by Amazon, not by us
Scores are our own editorial judgment, formed from published specifications and independent sources. They are not aggregated customer ratings, and they are not the result of hands-on testing, which we do not currently do. See how we choose.
Common questions
What is the correct ratio of greens to browns in compost?
Roughly two to three parts browns to one part greens by volume. Browns are dry carbon-rich material such as leaves and cardboard; greens are wet nitrogen-rich material such as kitchen scraps and grass clippings. You do not need to measure -- a handful of browns per bucket of scraps works.
How long does compost take to make?
A few weeks in a well-balanced, regularly turned tumbler in warm weather. Six months to a year in a static pile that is never turned. Cold weather effectively stops the process until spring, though the material does not spoil while it waits.
What should you not put in a compost bin?
Meat, fish, dairy, oils and cooked food, because home piles do not get hot enough to handle them and they attract rodents. Also cat and dog waste, diseased plant material, and weeds that have set seed unless your pile genuinely heats.
Why is my compost not breaking down?
Usually too dry, too many browns, or too small a volume to hold warmth. Add nitrogen-rich greens, water it to the dampness of a wrung-out sponge, and turn it thoroughly. A pile smaller than about a cubic yard struggles to build any heat.
Sources
Factual claims on this page are backed by the published sources below, and product specifications are the manufacturers’ own. Where a figure is not published, we say so rather than estimating it.