Compost is the best form of organic matter to add to your soil. It's a mix of organic materials, such as grass clippings, garden waste, and kitchen scraps, which have decayed into a crumbly, dark mass. A balanced, slow-release source of nutrients, compost can keep soils stocked with all the micronutrients plants need. It supplies small amounts of major nutrients and helps soil hold onto nutrients and water long enough for plants to use them. It increases the overall health of your garden by suppressing disease organisms in the soil. When sprayed on leaves in the form of compost ^a, it can suppress leaf spots, mildews, molds, and other leaf diseases. Compost also encourages beneficial soil organisms, which feed on disease organisms or make nutrients available to plants.
Compost is so simple that you might as well make it yourself instead of buying it. After all, you're just trying to speed up nature's nutrient recycling program, which goes on constantly all around us. There's no need for an elaborate system. Simply piling leaves will do if you're not in a rush. If you don't have deciduous trees, you can make concentrated compost — pUre humus — from kitchen scraps with a low-maintenance indoor worm bin.
If you want to make compost quickly, build a "hot," or active, pile. 1 nder ideal conditions, the organisms responsible for decomposition will experience a population explosion, generat ing a lot of heat. You need to m,x the l ight balance of materials that are carbon-rich and nitrogen-rich and turn piles often to give the organisms enough oxygen. If you'd rather uot bother with hot piles, you can make great compost using "cold," or Passive, piles. Just pile up whatever materials you have on hand and turn ,he piles rarely or not at all. (To speed things up, turn often and chop all mgredients before piling.)
■ Not-So-Secret ingredients 1 Siting Your Bin or Pile
1 Triple Bin: Cadillac of Composters
M-mv materials are good for composting. Including a variety helps SSe atlLan "d supply of micronutrient, Remember that tough Sals such as sticks and cornstalks take much longer to break down than softer materials, unless you chop them into small pieces.
The best compost is made from a mix of "browns" and "greens. Browns are dry or dead plant materials such as fallen leaves, straw, and wood shavings; they supply lots of carbon. Greens are fresh plant materials and fruit and vegetable scraps from the kitchen, regardless of color, that supply nitrogen and protein. The best sources of protein are animal by-products, such as manure, milk, blood, and wool; these don't fit into a color category.
The microorganisms that produce compost need a balanced diet of carbon (their energy source) and nitrogen-rich protein. Unless you use materials that provide a balance of these (see chart on page 57), top each 6-inch layer of carbon-rich material with a 2- to 4-inch layer rich in nitrogen. Or, add about a pound of nitrogen-/protein-rich material for every 30 pounds of carbon-rich material (about three-fourths of a hay bale). Extra-high-carbon newspapers and fresh sawdust need twice as much nitrogen-rich material to balance their effects. Anything that's already started decomposing has a more balanced content than fresh material and therefore needs less nitrogen. If you have too much nitrogen, the pile could start to smell.
If you don't want to bother keeping track, don't worry. Without enough nitrogen (assuming that no other factors in the "Compost Troubleshooter" on page 82 apply), your pile will still break down, only more slowly. It also won't heat up.
Master Gardening T
Any substance that speeds decomposition in your co pile is an activator. Generally, vators supply nitrogen (protei microorganisms, or both. Sa money by making your own fro the ingredients here. Avoid s thetic fertilizers, which contain n protein and seem to inhibit co post organisms. Activators w best if mixed in thoroughly, you'll be turning your pile soo simply spread a thin layer every inches or so. Use only 1 cup of di meal per layer but up to a 2-in layer of soil or compost.
Boost Nutrient Content
Some ingredients are added to supply nutrients to the soil when you ---
and T TP°St ™n SprinkHngS °f W00d ashes ^e potassium
SS^S T^ °f rk P0WderS Such as « and greensand supply potassium some N^SSiS; ntv D°n't add limes,0ne <0r «** *»" of «od ashes, which co ammonia „ J££X "a ™^ ~ * —
What to Use
Nitrogen-/ Protein-Rich ("Greens")
Fresh grass clippings
Kelp meal, seaweed
Legume plants (peas, beans, etc.)
Alfalfa hay or meal
Cabbage leaves, broccoli
Apple or winery pomace Blood meal Cottonseed meal Wool
Soybean meal Human hair Coffee grounds
Straw and hay Leaves
Pine needles (slow to break down)
Dry grass clippings
Dry, brown weeds and garden trimmings at season's end
Rice or cocoa hulls
Manure with bedding Well-aged manure Pea and bean pods Fruit peels, cores Vegetable peelings Sod and soil Fresh weeds Rotted wood
Soft, green garden trimmings
Weeds with seeds, or weeds that can sprout from bits of root fresh sewage Cbiosolids"), pet feces, used kitty litter
Nonbiodegradable items (glass, synthetics, pressure-treated wood)
loxic chemicals (pesticides, etc.)
Charcoal (as in briquettes)
Coal, coal dust, coal ashes oils, grease
^feat scraps, bones, cheese
What to Avoid ahd Why
May spread the disease if compost doesn't get hot enough.
Seeds or bits of root may survive and sprout in garden if compost doesn't get hot enough to kill them.
May carry parasites and diseases that infect humans.
Will not break down, so you'll just have to pull them out of finished compost.
Could kill composting organisms. Does not break down in compost
May contain levels of sulfur or iron that are toxic to plants.
Large amounts attract animals and keep anything they coat from breaking down.
Urge amounts attract animals and are very slow to break down.
Hoi composting and cold composting are the main systems; all the rest are. variations. Bins or boxes and tumblers are making hot or cold compost; many appeal" under "Survey of Composing Bms on pages 66-67. i fat tSS^ZSSvolume: Bins or piles must be at least 3 fee, by 3 feet and filled to about 4 fee, to allow for settling. Bins and tumblers that hold less than a cubic yard are only good for cold composing. The last three systems are easy alternatives to piles; all three are variations on cold composting.
Hot (fast) outdoor pile
Cold (slow) outdoor pile
Fast results; kills weed seeds and pathogens; more nutrient-rich than slow (cold) piles because there's less leaching of nutrients; less likely to attract animals or flies. Also called active composting.
Easy to start and add to; you can add material continuously, a little at a time; low maintenance; resulting compost is especially rich in beneficial soil organisms. Also called passive composting.
Neat appearance: holds heat more easily than freestanding piles; deters animals if covered; lid keeps rain from leaching nutrients. Can use for hot or cold piles.
Neat appearance; can produce compost quickly if ingredients are chopped finely and balanced; easy to aerate by turning; odor not usually a problem; no nutrient leaching into ground. Good for cold composting (usually not large enough for hot composting).
Garbage can Easy to do year-round; can be done in small space; (or plastic bag) requires little effort, though you must poke aeration and drainage holes in garbage can; inexpensive. Only for cold piles.
Relatively easy to turn material into adjacent bin; one bin can be used to stockpile ingredients while another holds unfinished compost Accommodates either hot or cold piles.
Easy; little or no odor; can be done indoors or out in a small space; can be added to continuously; castings are so nutrient-rich they can be used as fertilizer; good way to compost food waste.
Can handle large amounts of organic matter; no container or turning required; easy way to improve soil over large areas; boosts earthworm populations.
Quick and easy; no maintenance; no investment for materials; boasts earthworm populations; doesn't attract flies or animals; kills many weeds and diseases.
Requires careful management and lots of effort to turn and aerate; works best when you add a lot of material at once.
Takes a year or more to decompose; some nutrients are lost to leaching unless rtiln 1P nAtrÛWirl» /-"~t »-\ *S i '("i mimnln nnJ
pile is covered; can attract animals and flies; doesn't kill weeds or diseases.
Requires time to build or money to buy; decomposition is slow unless you turn materials inside bins; may need to add water from time to time.
Relatively expensive; volume is relativ small, rarely large enough to heat up as a hot pile; works best if material is chopped and added all at once; may m to add water from time to time.
Mostly anaerobic, so smell can be a prol> lem; can attract fruit flies; you must ensure correct carbon/nitrogen ratio to avoid a slimy mess; doesn't kill weeds or diseases.
Best for large volume of material; turning and aerating requires some effort.
Requires some care when adding materials and removing castings; you must protect worms from temperature extremes; can attract fruit flies; may not kill weeds or diseases.
Materials take several months to pose; requires effort to spread: kill weeds or diseases.
Requires some effort to dig pit or tre incorporates relative!) small amounts organic matter; improves only small
îo gkiat soil
Siting Your Bin or Pile
To start composting in your yard, first choose a good site Pick a rrfat;,, 11, I
finished compost uphill to the garden. If you plan to use- m nur *!' ^ W°n,t have t0 haul vou can:easily dump these nearby. Shade is .deal in hoTchmats-Z^T ^ ^ 8 SP°' whw
Lmpens composting enthusiasm like a sour smell waftingTta thi >'" t7 "°thing upX, from or riglu next to the house, at least not «EXttf^S? <*
If your site is in a low spot or is poorly drained, elevate the pile on a mound of soil, rot-resistant boards, or a discarded pallet.
DID VOU KNOW?
The Power of Compost: A Case Study
Researchers at the Connecticut Agricultural Experiment Station have been running experiments since 1982 to see how compost affects yields of common vegetables. While it took four or five years for the benefits to show, the results are impressive.
In some soils, compost can completely replace added lime (test your soil periodically to make sure). It also greatly reduces the need for fertilizer. Yields of vegetables from unfertilized soil given an inch (2.5 cm) of compost each year equal those grown in fertilized, but uncomposted, soils. Small amounts of fertilizer (preferably based on a soil test) really boost yields when teamed up with a little compost.
For the experiments, amendments were applied every year. Compost made from oak and maple leaves was sPread 1 inch thick on all but one of the beds. The control ^ got no compost but received the full recommended 0f fertilizer and lime. Other beds got ditterent founts of fertilizer and lime, plus the compost.
■After 12 years, the yield from the bed that got everything (full rate of amendments plus compost) was 25 percent higher than the bed that got no compost but just the full rate of fertilizer! Another bed got two-thirds the recommended fertilizer, plus compost; it produced similarly higher yields. And the plot that got no fertilizer or lime, just the leaf compost, produced the same amount of vegetables as the control bed!
The soil getting compost had almost twice as much organic matter as the bed with no compost. As a result, the compost-amended soil held nearly a two-week supply of water. This reduces plants' water stress and i fie need to irrigate. All that organic mailer also buffered the soils acidity. The pH of the bed that got only compost and no lime increased from 5.6 to 6.6. right into the optimum range. Later tests that substituted other types of compost for the leaf compost produced similar results.
No-Fuss Cold Compost
Anv pile that doesn't heat up is bv default a cold pile. If you don't want to fuss about ingredients and layers J exert the effort to turn piles, you don't have to. Cold compost is great for the garden. It contains an even wide| array of beneficial soil microbes than hot compost. It just takes longer to make.
Cold composting works well with any size or type of bin or pile. The simplest form of cold compost is leaf I mold. Pile leaves (chopped, if possible) in a corner of the yard and forget about them. In a couple of years you™ have wonderful leaf mold, which is just nature's compost. A fancy tumbler can produce compost relatively fl quickly, but many are too small for the contents to heat up, so these also make cold compost. Even a well- 3 layered, frequently turned bin may produce cold compost if it has too much carbon, the ingredients are too dry, or soaks it.
You can make cold compost anywhere, even in a plastic garbage bag. Unlike the other methods discussed in this chapter, this is anaerobic — oxygen-deprived — composting. The most noticeable difference is that anaerobic compost smells; people who make anaerobic compost unintentionally by creating totally soggy piles find this out. You won't be able to smell anything as long as the bag is sealed. Be prepared for a strong odor when you open the bag, though. Fortunately, the smell disappears quickly once contents are spread out and exposed to oxygen.
Fill a large bag with a mix of chopped leaves, grass clippings, and kitchen scraps. Or odd a' sprinkle of activator for every couple of shovelfuls of bulky, carbon-rich material until the bag i nearly full. Sprinkle a couple of quarts of water over the contents and mix until all ingredients are moistened. (Shake small or light bags- roll large or heavy ones.)
Tie the bag closed and leave in an out-of-
for a few months For faster results, turn it over every few days by simply rolling it on the ground.
Is It Done Yet?
Compost is finished when it develops the sweet, woodsy smell of rich soil and most ingredients have become a crumbly or fluffy, dark brown, soil-like material. Some large or recognizable pieces usually remain, but everything's a relatively uniform dark brown color. The center of a hot pile is no longer warm, and if you turn your pile it no longer heats up. After you've made a couple of batches, you'll recognize the difference between finished and unfinished compost. If you're not sure, try the following.
Master Gardening Tips
► To save oh fertilizer casts
A Simple Test
Soak a couple of large spoonfuls of your compost in a cup of water. Fill another cup with plain water (distilled is best, or let tap water sit overnight so chlorine can evaporate). Put 8 or 10 radish or lettuce seeds in each cup and soak them overnight. Dampen two paper towels. Strain off the water and spread the seeds on separate paper towels. Place towels _
in separate plastic bags and keep warm for a few days until the seeds sprout. (Check periodically to give them some air and make sure they're moist but not soggy.)
Both batches should germinate equally well. If there's a difference of only one or two seeds, it may be the seeds rather than the compost. If significantly more of the seeds soaked in plain water sprout, it shows that your compost needs to sit longer before being used near seedlings. Use unfinished compost only as mulch for shrubs or trees.
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