How should I avoid pests in an open compost bin

Question

I am starting composting. I have a pot (basically, a huge knee-high pot) that I want to use; it doesn't have much in the way of aeration holes, but it's open on top.

Two concerns I have are:

• Open bins bring more pests than closed bins
• I don't have existing compost to kickstart it with

What can I do to super accelerate the rate of composting (at least for the first run -- I don't have any existing compost, just a backyard) and how do I avoid those icky pests?

Bonus points for smell management. This might be my only shot at composting, and if I get bugs or bad smells, the wife will not permit future experiments. :(

Answer 1

In my opinion, an open bin is much better than a closed bin, but I'm not sure that what you have is really open enough:

it doesn't have much in the way of aeration holes, but it's open on top.

You need both drainage and aeration. I wouldn't use a pot, or if I did, I would make a bunch of holes in the bottom of it to both let excess water out and air in.

You have slightly conflicting goals: "super accelerate" and "no pests". If no pests (and no smells) is the most important thing, I would aim for slow composting by going heavy on the carbon side of the carbon/nitrogen ratio. Ingredients to do this would be autumn leaves, shredded newspaper, or [smaller amounts of] wood chips. Then add coffee grounds. If you absolutely do not want flies, and you want the first experiment to go well so your wife approves, do not add kitchen scraps yet. In the spring when the lawn is growing vigorously (at least it does here), I think it's ok to remove clippings from your lawn and add them in small quantities to the compost bin. (At other times of year the lawn clippings are a valuable source of nitrogen that you should leave on the lawn.) Always cover your "greens" (coffee, clippings, etc) with "browns" (leaves, newspaper, wood chips): this helps capture nitrogen from escaping into the atmosphere, and can help with smells. If you do this properly, your pile will not smell much more than earthy smell you'd get off the forest floor.

The end result of this pile will not be super rich compost. It will be more like leaf mould -- slightly richer. But it makes a really nice amendment for your carrot beds or other root vegetables that don't want over-rich soil but do enjoy loose soil with lots of organic matter.

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In terms of "accelerating", you should add a thin layer of healthy garden soil on top of your pile to help inoculate it with the bacteria that will start breaking everything down. This is a good practice even if your primary aim is no pests/smells.

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If your primary goal is a "fast" pile, and you can tolerate some risk of smells and flies, then you can aim for a 30:1 carbon:nitrogen ratio. This would mean not using wood chips or sawdust, since they are very high carbon -- stick with newspaper, straw, or autumn leaves (ideally shredded). And add more nitrogen-rich materials like lawn clippings, coffee grounds, human hair (very thin layers), "vegan" kitchen scraps (no meat or dairy), small amounts of poultry manure if you have it available, etc -- but not too much nitrogen, and only in thin layers between the browns. You may need to add water if your feedstocks are dry. The pile should heat up within a day or two. When the pile starts to cool off, turn it, and it should heat up again. Repeat; when you turn it and it doesn't heat up, then it's probably nearly fully composted.

If you get bad smells, use them to diagnose and fix problems (e.g. too wet, too much nitrogen). The normal smell for this is "barnyard"-like as described by @Ed Staub in his answer; I find this to be a pleasant smell, but I grew up around a barnyard full of animals, YMMV.

HOWEVER, a hot pile has a critical mass -- I've typically seen 3x3x3' recommended for a pile size, which about matches up with my experience. Any smaller and it won't heat up; much larger and the interior doesn't get enough oxygen and it's hard to turn. It doesn't sound like your bin is big enough to qualify -- so it won't heat up.

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I recommend using the slow method I outlined above: you're more likely to have (eventual) success, less likely to have bad smells, less likely to have pests. As you gain experience, you can start adding small amounts of kitchen scraps (i.e. gradually decreasing the carbon ratio) and see how it goes.

Answer 2

Put it in the shade, cover it, and get a pound of red worms... Vermicomposting is much faster, and the resulting worm castings are more valuable than compost.

Answer 3

I have been doing this same thing with good success.

I drilled about 6-8 holes on the side near the bottom for drainage. I usually add lawn/ garden clippings, weeds, food scraps (no meat or dairy) and spent grains from brewing beer. I am not sure on the exact percentages of each but as they say "Compost happens". It can get pretty warm in there, and I do have to take a shovel and turn it about once a week, more if it rains.

To keep away pests (mainly only flys) I place about a 4 inch thick covering of lawn grass/hay that covers everything below.

To prevent smell I and pick a few vines from my mint to set on top. This keeps the mint a little more under control and makes them not smell at all.

The only problems I still have is maggots (at least I think they are) that show up if I don't turn it often enough. but they just die when it dried out and compost out as well.

Answer 4

Compost needs oxygen, water, nitrogen, carbon, and bacteria. If you don't have enough oxygen, the pile can go anaerobic which stinks - literally. So your precautions may cause what you're trying to avoid if you don't somehow aerate.

"Super accelerating" means having a good mix of everything - most notably, the right amount of nitrogenous stuff. But the fastest pile will put out a lot of smells too - though a lot more pleasant, barnyard aromas than the dead-body smells you can get from an anaerobic pile.

The easiest way to keep from getting too much smell is to control the amount of water.

As for pests... to avoid carnivorous mammals, never put meat or bones in compost. Use good judgement on insects - if whatever you're putting in would normally attract a lot of flies, be sure to turn it in. You will get a lot of other insects in the pile, but in my experience, none I'd call a nuisance.

I'm guessing a lot about holes, drainage, etc... but I'd be worried about there not being enough aeration and drainage, especially if you get a lot of rain. If that's a concern, you might want to put a removable "roof" over it that leaves it open to air but keeps some of the rain out.