When composting, "everything works". Details of the "right way" to build a compost heap only matter if you want to win a prize for "fastest heap in town", or "hottest heap".
True, a really hot, fast heap will kill more weed seeds than a cool, slow heap, but you could also avoid throwing weeds that have gone to seed into your main heap.
If you worry about pathogens from animal manure, or persistent herbicides or pesticides not breaking down, then you may want to make the hottest heap you can make, and age it further after it's done composting. And/or test it for herbicides before you add something to the heap or before you use the finished heap.
Almost everyone I read is careful to thoroughly compost most fresh animal manures. I think rabbit manure may be an exception. Cat poop is especially bad. It contains oocysts that persist in the soil for up to ten years and they actually CAN infect humans. (Google "oocysts of toxoplasma gondii").
The only way you could not succeed at composting is if your neighborhood association nags you.
Or wild animals could drag away your food scraps before they decompose. That's why most people won't compost meat or fatty scraps or dairy. I have gotten away with burying small amounts of spoiled meat deeply in the pile.
There are some invasive plants that spread by runnering (ivy and Burmuda grass). Don't compost them. Maybe roast them in the sun and burn them, then drive a stake through their hearts.
Instead of making a compost pile, you could sheet compost ("lasagna gardening") or spot compost (bury it in holes between rows).
No matter what you do with organic matter, it will rot.
(Just don't seal it tight in plastic bags and store it in a freezer.)
Well, a compost pile could go smelly and slimy if 2-3 things all go wrong at the same time:
- not enough air,
- and too much water,
- and too much "green" high-nitrogen stuff.
One fast fix is to deny it water. Dry compost rots very slowly, and then any amount of air is enough to make it smell OK.
The very best fix is to throw down an amount of paper or sawdust or brown shredded leaves equal to the pile you already have, and turn the slimy stuff on top of it. The anaerobic N-rich slime will soak down into the paper or leaves and cure itself. And then it will all be ready to use very soon.
But there are many ways to fix a slimy, smelly heap. The cause is that it is decomposing too fast for the amount of air that can diffuse in.
Air 1 -
Turning the heap will mix air back in.
Air 2 -
Throwing in some twigs or stiff stems from yard waste as you turn the heap will also keep it "fluffed up" so it has enough air whether you turn it again or not.
Air 3 -
Making the pile smaller or not-as-tall lets more air in.
Air 4 -
Clever people will use a length of rebar or pipe to punch or drill holes into the pile. If you "build the rebar into the pile" as you turn it or build it, it's easy. Just push it back and forth weekly with some heaving or cork-screwing to open an air channel.
Air 5 & Excess Water 1 -
Very clever people will throw down a layer of branches and twigs on the ground before they build up the heap. This will hold the heap up a little, and let air come in from underneath. It also helps excess water drain out if you have heavy clay soil.
However, as the OM decays, it will sift down and fill that air space, at which point you have to pull the twigs out or screen them out. I don't like that method because I like to shovel the black, crumbly bottom layer out, and spread it on top of the heap, or use it right away in my garden.
Excess Water 2 -
Stop adding any water. If it rains too much, shape the top of the heap to shed rain, and try to cover it with big leaves or part of a tarp or plastic bag.
Excess Water 3 -
Or build your pile under a tree with lots of leaves (but try to avoid tree roots taking over your pile). Pine tree roots sucked all the goodness out of my pile once.
Too Much High-N "green" stuff.
There can never be too much compost! Therefore, it isn't "too much green", it is really "not enough brown". Adding mostly-carbon stuff will make your pile much bigger and you'll get more compost out of it.
I think of the greens as expensive spices, or as the roast beef in a sandwich. The browns are the less nutritious bread or mashed potatoes. If I have too much roast beef for one sandwich, I make two sandwiches!
If I need lots of compost but only have a few greens, I use lots more brown than green, even if it cooks slower or is less rich when finished. The soil needs organic matter, and there are many cheap ways to add nitrogen.
- brown leaves
- shredded paper or any paper including newspaper or cardboard
- sawdust
- chipped wood, but chips and twigs break down SLOWLY in most climates. So FINELY chipped wood is better
- rice hulls
- cotton waste?
- mill waste
If you have a lot of paper or cardboard, but don't want it to mat down and choke out air, you can soak it and then tear it by hand or chop it up with a mattock or shovel. (Tip from Dave, I think)
Or alternate layers of paper and stiff green stems. When it does start to mat down tight, then chop it up with a mattock so it's easier to turn, and do turn it often enough to let air in despite big pieces of paper or cardboard.
Currently, my best source of high-N "greens" is a fruit stand where I buy apples. They let me take away supermarket bags-full of their discards. Not all are rotten and stinky!
