I grew up with compost. My father Herschel Roberts had a large compost bin in the back yard and grew some of the best flowers and vegetables in the neighbourhood. He composted for 40 years. When my wife and I became homeowners 23 years ago we set up our own compost bin. Five years ago we moved to the country, to a sandy plain, and we've set up a new compost pile (larger than a bin) and are trying to build up the garden soil here to be as good as it was in the old place. We keep making compost and working it into the soil, and every year the garden produce grows a bit more lush and tastes better.
This article presents some thoughts about composting based upon personal experience. I don't claim to be an expert; nothing about our composting has been carried to extremes, and I can't tell you about the intricacies of bacterial action or horticulture. This is just for fun, to share some of our observations. And, I think you might like to build yourself a compost sifter using the design described near the end of this article if your compost operation is on a similar scale to ours: not too small, not huge.
Our compost pile is built in a square 10 ft by 10 ft, divided into four 5 ft by 5 ft sections. The boards around the sections are only 6 inches high but higher boards, up to about 18 inches, would also be suitable and would allow material to be piled higher. In metric, that's a pile 3 meters by 3 meters, with sides 15 to 50 cm high.
The compost pile is located in a sunny spot since we live in a cool climate. In a hot dry climate we would try to locate the pile in shade so it would tend to retain moisture.
The four sections are different stages in compost production:
The first three sections overlap, and are more of a concept for placing material than a strict categorization. We do try to keep the sifted compost clear of new material.
Anytime one of us is planting we can take a few shovels of compost out of the sifted section. At the end of the year some of the sifted compost is dug into the garden as we clean up the beds, and some is left over the winter and will be dug into plantings the next spring.
Almost any plant matter can go into the compost pile. For example, grass clippings, coffee grounds and filters, fruit peels and pits, weeds, spoiled potatoes. The compost pile receives kitchen scraps (we keep a little pail under the sink and empty it every couple of days), the plants we pull up from the garden, weeds from the adjoining field gathered when they get lush and worth some time, ashes from the wood stove, small amounts of clean sawdust, shredded oak leaves, eggshells, potted plants and much more.
We've been fortunate to get the compost bucket from my wife's work every other weekend (sharing with another compost enthusiast). The people at work are careful about what goes into the bucket, and we can just dump it onto the compost pile here without sorting.
Variety is important. You do not want your compost pile made up of a large proportion of a single simple material. It is easy to get large quantities of leaves, straw, sawdust, and pond muck but these can overwhelm the other materials if applied too thickly. Mix it up, include some kitchen garbage for "spice", pick a few weeds and throw them on, be creative. Making good compost is like making homemade soup for the delection of the bacteria and worms who are doing all the real composting work for you.
Recycle your finished compost. Pitch a bit of the digested compost, and especially a bit of the compost which is partially digesting and still actively working, back onto the new material pile. This will give the new material a good start with lots of bacteria and bugs.
During the summer we don't put fat into the compost pile because it smells bad and attracts animals - that is, no bacon grease, meat scraps, or salad dressings in quantity. A bit of salad leftover with dressing on it is OK, in our rural setting, but we would not put even that much oil into an urban compost pile. On the other hand, some people compost even their meat scraps. This past winter we've been putting a few meat scraps onto the compost because it gives the wild cats and foxes some protein, we're quite a distance from the pile which is up in the garden, and there are no neighbours to be bothered by anything. This is a new practice though and I don't know if we'll be happy with the results in the spring; we'll see.
Don't ever put poison ivy vines into the compost pile, since the oil in the vines will not be destroyed by the heat of composting and may cause rashes when you work with the compost in later years.
Nothing toxic should go into the compost. For example, yew trees and bushes are poisonous to people; discard their clippings elsewhere. You would not likely be harmed by the slight amount of yew toxin which was carried through your compost into your food, but why have any toxins at all in your food chain?
Sunflower seed hulls, heads, stalks should also be excluded. They are toxic to other plant life, so why put them in your garden? You may have noticed that around the base of a birdfeeder where the sunflower seed hulls have dropped there are no or few plants.
Many people exclude hard materials from their compost pile - woody stems, fruit pits - but they do eventually digest. It depends on how patient you want to be in working your compost pile. You may find that gathering a larger quantity of weeds is more efficient in producing the same quantity of compost.
Newspapers are not composted here because we don't like the idea of eating printers ink. Similarly, although we compost wood ashes from the stoves (we burn only clean wood, no paint, no cardboard or paper which has printing on it) we do not compost any other ashes. Those go to the dump.
Be careful of sawdust, since it can contain undesirable fungus-killing wood preservatives unless you get it from a place which you know uses untreated lumber. You want the fungi in your compost and later in your garden soil; they are essential for transport of minerals and other nutrients to the roots of plants. In any case, too much sawdust can inhibit the composting action. The simplest thing is to only add sawdust when you have produced it from your own work and know that no pressure-treated wood was involved.
My personal experience with muck from the bottom of a pond has not been satisfactory; it does not appear to be very rich and takes a long time to digest. But in moderation and mixed around it can add body to your compost and give you more to work with. I would not go to very much trouble to obtain pond muck though.
Cat litter and other pet waste has no place in the compost pile. It may contain worms and other parasites which can get into the garden food chain. We have a separate pit, away from the garden and compost pile, where we can dump the cat litter and sprinkle dirt over it.
It is not necessary to aerate your compost pile but you will get good compost quicker if you do. Two or three times in the year turn your compost to get air into it. Use a spade fork and simply dig around a bit in the pile. If you have a multi-section pile and feel energetic you can turn one section over into another. Do major turnovers only once in a while (once a month at most) since you can otherwise disturb the digestion of the pile.
Nothing should be too thick or tightly packed. You want air in the compost pile. For example, grass clippings will pack down and become slimy if left a week. A few days after dumping a bunch of grass clippings on the compost pile, take a spade fork or shovel and loosen them up so that air gets in and they will continue to digest cleanly. Similarly, if you put leaves or straw on the compost pile, put moderate amounts on at a time or chop them up first with the lawn mower.
On the other hand, one of the wonders of composting is that given time almost anything will digest. If you have slimy compost with the bad smell of anaerobic bacteria, simply giving it a stir with the spade fork to let air in will soon enable it to complete digestion aerobically and will produce clean sweet-smelling dirt.
I'm not fond of the commercial black urban composting bins. They seem to me to be mainly a concession to appearances, as they do not have nearly enough air holes to produce good compost. But, even with the output of such a composter, once you get the material out (which aerates it) and let it lie around in the sun for a week you should have good results and a compost which you will not mind handling.
To get the best finished compost for gardening you should sift it. Not strictly necessary, and not possible for a commercial operation, but desirable when making compost for a home garden. Besides ensuring that you exclude larger sticks, stones and undigested materials from your finished compost the sifting process also aerates any undigested material and speeds up its further decomposition. Sifted compost, even if not fully digested, is fine enough to be dug into the ground as-is; any further digestion will be completed there.
The mesh on your sifter should be one-inch (2 or 2.5 cm) spacing, not smaller. One might think that a smaller mesh would be better as it would pass only small particles of dirt, but in practice a half-inch mesh will clog up when the compost is at all moist and you will waste lots of time cleaning the sifter mesh.
To sift our compost, I built a low-cost sifter which looks like a tall wobbly table. The legs are 4 feet high and thin (2 x 2) lumber, so the table will wobble back and forth if you push on the edge. The top of the table is a tray with sides made of 1 x 4 lumber and with 1-inch mesh on the bottom. Those dimensions in metric: legs are 1.3 meters high, made of 5 cm by 5cm lumber. Sides of sifter tray are 2.5 cm by 10 cm lumber, and the bottom mesh is 2.5 cm square.
In use, one positions the sifter over the section to receive the sifted compost, shovels partly digested compost into the top of the sifter, wiggles the sifter until the new dirt falls through, and then dumps the larger materials back into another section of the compost pile to be digested further.
Using a sifter with legs saves lots of back work. My old sifter was handheld and it was exhausting (though it did a good job). It was suitable for the smaller 3 ft by 3 ft compost pile we had years ago, but the new pile is ten times as large. With a handheld sifter, one has to hold the weight of the compost in the air while shaking it, and one has to do all the shaking using arms and shoulders.
How do you know if you've got great compost? See if large earthworms will thrive in it. They will also keep the sifted compost aerated, and will benefit the rest of your garden soil. The more earthworms the better.
If you have composting advice or questions, please reply by email. I'm no Mr. Compost but I'm always happy to exchange ideas.
E-Mail: Ken Roberts ken2@mirror.org
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http://www.mirror.org/ken.roberts/compost.html
Last revised September 2, 1997 by
Ken Roberts
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