Composting really isn’t a cut and dried activity; it’s more like what happens when you let things sit around and rot. Managing composting is about which things you let rot, and where, and how much you mess around with them while they’re rotting. It’s also about how the weather conditions where you live affect the process.
I’m going to focus a bit here on composting in the desert, because that’s where most of my experience is. Warm wet things rot fastest, so the easiest aspect of composting in the desert is the heat, and the most difficult is the dryness.
Ideally, a compost pile will not be wet (or not much of the time) and not dry (ever, if possible) because the microorganisms that are doing the work for you will die back. You need moisture, and warmth, but you also need air, or else you will have anaerobic compost, which smells bad. A well-aired and well-balanced compost heap shouldn’t have any strong or sharp smells. And, if you want it to get to 165oF inside, it has to be five feet or so across each way, and even then, it will be hard to kill everything you want to kill. An active compost pile is one that gets that hot and kills weed seeds, damping off virus, etc. A passive pile is one that does not get so hot and whose function is more simply decomposition.
There are a number of ways to get air into compost, and they are defined by the structure of the heap and the container (if any). Also turning the compost will help air it and speed the decomposition process; you can do this as often as every week or so, though most people aren’t that industrious. Turning also will discourage rodent infestations.
It is possible to purchase expensive plastic containers for composting. I do not recommend this unless you are willing to get one on a spindle that you can rotate with a handle. Otherwise, you can buy a plastic trash can or tote bin for less than $10 and drill a lot of ¼" holes in it (or fewer larger holes, if you wish). I like smaller holes because that keeps the mice out. You don’t really need to have holes all the way up the sides, and you don’t need them in the bottom; just enough for drainage and air circulation towards the bottom. A lid is good, to keep the moisture in and rodents out.
Weeds are an excellent additive to compost piles, if you don’t want to use them for mulch. I use weeds for mulch a lot when they don’t have seeds or rootable material, and sometimes if they do, if they aren’t especially invasive. If you don’t mind a messy looking garden, this works well to conserve moisture and feed the soil directly with the decomposing green plants.
Materials you put in your compost have varying percentages of nitrogen and carbon in their composition. This is an important thing to have some sort of handle on, as nitrogen is required to decompose carboniferous material, and if you have too much of the latter and too little of the former, your compost will decompose that much more slowly, or you will have to use more water, and/or add something else that has enough nitrogen to balance things out.
Conversely, too much nitrogen in the contents will get you compost that volatilizes the excess nitrogen, which won’t smell good (and is a waste of nitrogen as well). Almost all composters have an easier time finding carboniferous material than they do enough nitrogen. Carboniferous material includes wood and dead leaves; nitrogenous material includes animal wastes such as manure and urine, and also synthetic nitrogen additives such as ammonium sulfate or urea. Leguminous plant waste is relatively high in nitrogen as well (which is why it’s used as a green manure, grown and then dug directly into the soil) and thus is also especially useful in compost piles. Fresh green weeds, grass clippings, and kitchen vegetable trimmings are pretty well balanced in the carbon/nitrogen department, roughly about 10:1, while stuff like wood is closer to 100:1, to give you a rough idea.
If you don’t want or need to use plastic containers, you can easily build a simple container with chicken wire and pallets, or even just chicken wire. Setting a layer of chicken wire raised a few inches off the ground under the compost is a good way to aerate the bottom, too. However, if you live where it’s windy and dry and hot, chicken wire will let the compost dry out too fast and it will decompose much more slowly as a result, so you will want to design a container that has more solid walls. Something as simple as a damaged plastic tarp can help a great deal.
Another method is to dig a hole. There are two approaches I’d recommend: the small deep hole approach and the wide shallow hole approach. The deep hole approach can be effective when dealing with difficult soils, such as caliche substrate, where you essentially have to mine out the substrate to create the hole. Assiduous desert gardeners have actually created soil and gardens by doing this over and over again until they have made what might be considered buried planter boxes.
With more malleable soil, a large shallow pit can be effective, but if you go down very far, one way or the other it’s going to be harder on your back. People who live in damp climates don’t really need to be digging holes; it’s a better strategy for desert gardeners.
I’m currently working with my compostable materials in several different ways. I have one heap on the ground with sticks and small branches on the bottom for aeration, and that gets all the weeds and yard trash I don’t want to mulch with or use for garden supports. I keep it covered with a tarp that has holes in it (I trashpicked the tarp that way) and water it occasionally, including with dirty dishwashing water that I use greywater-friendly soap for; it has a little nitrogen so that helps.
This is a fairly high-carbon heap, and I don’t put anything in it that I don’t have to. I do put Bermuda grass roots in it, but only after I’ve let them dry in the sun for a number of weeks so they will be less likely to re-root. It also gets the dead morning glory vine, because morning glories become invasive and I am already weeding out more of them than I need to. This pile would decompose faster if I had some animal manures to work with, but if I did I think I’d probably compost them separately and work them with leaves. One of the tricks of making composting simpler is to remember that the most problematic substance you put in your compost pile is going to determine the lowest common denominator; i.e. do you really want to keep sifting out all those pecan hulls, over and over again? Etc. I’d much rather take the leaves in the fall and work them separately in a fast heap so I have some finished organic matter to dig in by winter.
My kitchen scraps go into a perforated plastic trash can as noted above. Since kitchen scraps can run a bit higher than 10:1 C/N, I layer them with paper scraps; using used unbleached coffee filters, paper towel and toilet paper tubes and trimmings from cardboard boxes (I use the cardboard as packing material in another endeavor), and also used paper towels. I try not to use a lot of paper towels, but I like to use a bit of one to clean a cutting board, as sponges get so germy so fast, and one can always use recycled paper towels (as well as toilet paper), so I figure this is pretty environmentally friendly.
I keep the used coffee filters separate up front; let them dry out and collect the grinds and generally distribute them in the garden, as there is no particular reason to let whatever potassium content they might have leach out in the compost.
Another thing I keep separate is citrus rinds. They compost slowly and I’ve read enough about citrus being an ant repellent that I’ve decided to experiment with using them to repel harvester ants. These large ants are quite common in these parts, and they are an important part of the ecology if only because they are by far the preferred food of the Texas horned lizard, whose endangered-or-not status is always a little shaky these days. Harvesters are not the most aggressive ant species in the world by far, but they have one of the worst stings. One ant can give you a sting that is as bad as some wasp stings, and since they tend to wander around everywhere looking for seeds, it’s easy to miss seeing one and get stung, especially for those of us with a penchant for going about barefoot.
Harvesters tend to prefer to nest in hardpacked dry soil, which makes the easements on the streets around here often ideal for them. If one’s adjoining garden happens to be packed full with interesting small seed, it can be hard to keep them out. I’m hoping that distributing citrus rind regularly along the fence line will help to confuse and/or repel them, and also I distribute a little bird seed and meal out on the easement, and give them a bit of water regularly. This may sound nuts, and indeed it may just lead to more harvester ants, but if they come inside the yard I’ll just keep trying things like citrus infusions into the nest, because I really, really don’t want to kill them, though I have at times. If you’ve ever found baby Texas horned lizards hopping about your garden, I’m sure you’ll understand!
And in fact, they will not hang around an area that doesn’t have seed, so as with so much arthropod management, working out what the animals are eating and making sure there isn’t any of that food where you don’t want the animals to be, is an effective strategy.
Speaking of invertebrates, worms are used by some to compost their kitchen scraps. This is a neat idea and can be done indoors even. Red worms are composting worms; earthworms are for the garden. You can buy red worms and work up a worm bin out of a plastic tote bin lined with layers of newspapers and kitchen scraps and probably some dirt. I’ve never done this but it probably is pretty simple if you play around with it. You’ll have to make sure it all stays a bit moist, though; worms won’t like being dried out. I can’t recall ever seeing anyone around here selling red worms (though you can buy nightcrawlers at Walmart here in the hunting/fishing department, at least you used to be able to) or I’d have tried this by now.
I’ve mentioned that compost can (and often will) attract rodents. If you’re in a situation where you feel the need to trap for them, here are a few ideas and techniques that have worked for me.
I don’t use live traps, as house mice and Norwegian rats are problematic and common enough that I don’t care to spend my time attempting to relocate them. I also don’t use glue traps, as they are excessively cruel, and I don’t use poison, because the rodents may be eaten by another animal before dying, or conversely they may get you back by making the interior walls of your house their deathbeds. Snap traps work.
Rats are smart; they will learn to be trap wary if you don’t get them the first time. House mice, not so much. Traps with sensitive triggers work better, but if your traps do not have sensitive triggers, use some kind of hard bait that you can jam on the tab so the rodent is forced to move it to get the bait off (nuts, cheese). Otherwise, peanut butter is a great bait, and vanilla extract can be quite effective for getting the attention of the animals in the first place.
I hope this all is of some interest, and as always I’d be happy hear from any of you about your tricks and tips as well.