Composting: Part 1
I now have a garden, complete with baby vegetable plants and herbs. But before I had the garden, I had a compost pile. I wanted to grow our garden sans chemicals and artificial fertilizers, so I read a book about composting and another book about organic gardening and companion planting. What follows is a brief but hopefully thorough account of what composting involves. Don’t be intimidated by the length of this post. The main thing you need to know about compost: if you pile a bunch of organic matter, it will rot, whether or not you follow all of these tips. Have fun with it! All information is from Let It Rot! The Gardener’s Guide to Composting by Stu Campbell.
Compost is decomposed organic matter (leaves, manure, food scraps, etc.) used as fertilizer and to enrich the soil. It is usually made by piling organic matter in some kind of heap, layering different ingredients every two inches or so. Finished compost is dark and crumbly, earthy smelling, not rotten and moldy.
Compost needs the following to work:
1) An energy source, or carbon
2) Protein, or nitrogen
3) Oxygen
4) Moisture
Carbon is dry, tough, fibrous plant materials like leaves, straw, sawdust, cornstalks, leftover food, and other bulky plant material from the yard or garden.
Nitrogen is the activator for the compost pile, the “digestive enzymes,” the stuff that speeds the decomposition process. Examples are: manure (bat guano, cow, duck, goat, goose, hen, horse, pig, pigeon, rabbit, sheep, and turkey), green manure (buckwheat, rye, cornstalks, tomato vines, pea plants, thick rooted crops like kale), grass clippings, green vegetation, blood meal, kelp meal, alfalfa meal, bone meal, cottonseed meal, fish meal, hoof meal, horn meal, finished compost, and soil. Nitrogenous materials are not as bulky and fibrous as carbon materials, and they should be added to the compost pile in smaller quantities than the latter. If your compost doesn’t have enough nitrogen, decomposition is slowed; but if there is too much of it, then the pile smells of ammonia gas. Yuck.
Oxygen is the air we breathe. And it is required by aerobes, the microorganisms that work to breakdown (eat) everything in the pile. If you don’t have enough oxygen, then the anaerobes take over, and they slow down decomposition by about 90%. And they’re smelly. Aerobes, however, break down carbon into carbon dioxide and water, and they produce energy (heating up the pile). Aerobes use this energy to grow faster, and therefore decompose more material. They also excrete nutrients, like nitrogen, phosphorus, magnesium, etc. “Aerating” your compost pile is therefore very important (i.e. turning the compost with a shovel or pitch fork) because it gets more oxygen into the pile. Turning your pile more often means decreased decomposition time. Aerobic activity in your pile is more desirable than anaerobic, but remember, both are breaking down matter in the pile.
Moisture comes from the sky or your garden hose. If compost has too little moisture, decomposition is slowed. But if there is too much moisture, the oxygen is forced out, suffocating the microorganisms. Keep the moisture level between 45-50%. Remember to moisten the compost pile as you build it, and it will stay moistened.
Insects are an important part to the composting process. They are the bigger eaters compared to aerobes (bigger in size). Earthworms signify good microbial activity. They produce their weight in castings (their poo, which is nutrient rich) each day. The only critters you don’t really want near your compost are pets and raccoons and such. But most likely, that won’t be a problem. No neighborhood cats or roaming squirrels have taken a second glance at my compost.
FORMULA FOR GOOD COMPOST= 2 Parts Vegetable Matter (carbon materials) + 1 Part Animal Matter (nitrogenous material)
Compostable materials:
Wood Ashes These are a good source of potash (potassium carbonate), and they are a pest deterrent. You can also burn banana skins, lemon skins, cucumbers, and cocoa shells, which have a high phosphorus and potassium content.
Feathers A good source of nitrogen!
Garbage As in kitchen garbage. Bury meat scraps deep in the compost pile, or don’t use them. Larger critters are looking for these especially.
Grass Clippings If using green clippings, layer them into the compost in thin layers; these heat up the pile very quickly. Or you can dry them out first and mix them with other dry absorbent materials (like dead leaves).
Ground Stone / Shells Mineral rich. Pulverize oyster, clam, and lobster shells.
Hay and Straw Old is better. Bacteria use up nitrogen decomposing these if the hay or straw is too new and in too large amounts.
Hedge Trimmings Chop or shred these first. Or if you add them in smaller amounts, leave them unchopped to allow good air penetration.
Hops (brewery waste) No need to water your pile often if you use lots.
Leaves Rotted leaves are the closest thing to pure humus. Use thin layers if your leaves are whole. 5 parts leaves + 1 part manure would make good compost.
Leather Waste (dust) High in nitrogen and phosphorus.
Newspaper Carbon source. Use sparingly and/or shred as finely as possible.
Peat Moss When mixed thoroughly, this is a good texturizer and conditioner. Remember that it rots very slowly.
Pine Needles Also a good texturizer, but don’t use them as the main ingredient. Very slow breakdown and acidic (which some soils need. Contact your local Cooperative Extension Service Office for a soil testing kit to find out what kind of soil you have).
Sawdust Work this in thin sprinklings, sandwiched between manure. Softwood breaks down slower than hardwood. And weathered wood is better.
Seaweed and Kelp Potassium! Not to mention boron, iodine, calcium, magnesium, sodium, and other trace elements. Also a good insulator in winter (as a thick blanket overtop).
Sod Another good insulator. Adds loam and organic matter to the pile.
Weeds Be careful putting these into your compost, because you need sufficient heating to kill the seeds. Avoid them if your pile doesn’t get hot enough.
Chop up stubborn materials like: corncobs, apple pomace, citrus rinds, cotton stalks, sugar cane leaves, palm fronds, cornstalks, peanut hulls, walnut, almond and pecan shells, thorny things (”they can bite you later”).
Avoid: mud, sand, gravel, coal, charcoal, glossy colored paper (unless shredded), diseased plants, non-biodegradable items, pet litter, sludge (human waste), and toxic chemicals.
Composting Methods:
Classic Three Pile Method Set up a pile for each of the following: newly decomposing materials, “cooking” compost, and finished compost. The size of each pile shouldn’t exceed about 3 feet square or high. And they can be constructed as independent piles, in a wooden frame (like with chicken wire sides to allow sufficient aeration), or in plastic drums you can buy for composting. My piles are just free standing next to the garden. The drum method keeps everything contained easily, but they seem difficult to keep aerated.
FAST Composting: The University of California Method
1) Chop or shred to increase surface area of materials.
2) Blend nitrogenous activators throughly with carbonaceous material (like in a “layer cake”).
3) Frequently turn the compost, every three days at least, to improve aeration and expose all materials to heat at the center of the pile.
This is the composting method I’ve adopted, and it has worked well. You can have finished compost in just a couple of weeks (it takes months if you don’t turn it very much).
When To Add Compost Partially decomposed compost can be mixed into the earth before planting a garden to help loosen clay soils, and it is good in warm climates where decomposition is more rapid. Well decomposed compost should be mixed in when planting seeds, plants, or added on top of the garden; it helps sandy soils retain water and moisture and is good in cool climates.
Compost Tea is a good boost of nutrients to your plants. Mix 1 part compost to 5 parts water and stir several times. Let sit for several days, and then use it to water the garden. It is especially good for new transplants, house plants, and new seedlings.