Myth 1: Start a compost pile to manage grass clippings
Why not try mulching before composting? Making piles of organic materials is more work than letting them lie. Instead of bagging, why not try "Grasscycling" or the "Don’t Bag It" system of using mulching mowers instead? There is no reason to bag grass if you cut it more often, use less fertilizer, and leave the grass higher. Composting (making piles) is a last resort, and should be practiced only when mulching is not practical, unless you want to make compost.
Myth 2: A compost bin is a compost bin; go with what is cheapest
Not all compost bins are the same. You might regret purchasing or building a compost bin that is not suited to do what you want the bin to do. For table scraps, for example, you might consider a worm box instead of a compost bin. Some people believe they can just let their organics sit for years without ever bothering with a bin at all! The two purposes of a pile are to hold heat and moisture. If your goal is to "hold" materials such as leaves for a year or so, a large open-air holding bin is most practical. For active, hot composting, smaller enclosed plastic bins are preferred. Bins with sidewalls may make turning more difficult. Wire bins may rust and decompose quickly.
Myth 3: Form layers in the bin
Even if you are using a passive composting system, it is better to mix ingredients together outside the bin first. Nearly every other composting guidebook or brochure has a picture of layers of organics inside the compost bin. The point these guides are missing is that organics should be layered and moistened outside the bin, not inside of it. The act of forking everything over into the bin, mixing it all together as it goes, is the key, missing step. Layers of organic material will not cook or heat properly until they are mixed. While it may seem that mixing materials together is extra work, this initial mixing stage can eliminate the bothersome job of turning a ripe pile in order to mix it later. I recommend mixing at the beginning before stuff gets stinky.
Myth 4: Add topsoil to inoculate the compost pile
Old compost is a better inoculant than topsoil. Adding topsoil to the compost pile is another myth that many composting educators are trying to get removed from the composting brochures and guides. Adding soil to a compost pile is like adding soil to a campfire; it puts the fire out! Soils are mostly minerals and add little other than weight to the pile, making it more difficult to turn and use. Topsoil adds no "fuel" to help the composting "fire". The idea behind adding soil is to inoculate the pile with a healthy culture of soil organisms that colonize the pile and "jump start" the active, hot composting process. The best source of this inoculant, however, is older compost. The trick is to always save some old compost from previous batches to mix in with the fresh material.
If this is your first pile, try old leaf mold from under trees. If that is impractical, buy a few bags of composted manure from the garden center. Adding a little packaged inoculant may help if it contains an active biological culture. A rich loamy garden soil should be used only as a last resort for the very first pile, never as a standard ingredient.
Myth 5: Add lime
There is no need to ever add lime to a compost pile. It can actually make things worse. Compost goes through natural pH changes, including an acidic stage while the pile is active, and a sudden rise in pH from adding lime can actually kill a whole generation of beneficial organisms! Lime also has the disadvantage of releasing and losing valuable nitrogen, which can actually create a foul ammonia smell. Lime may be added to acidic soils, but it serves no beneficial purpose in the compost pile.
Myth 6: Don’t add walnut leaves, eucalyptus, oleander, or rhubarb in the compost because they contain toxins
Everything that was once alive will eventually decompose back into humus. It is impossible to determine what plant or animal products comprise the humus by analysis. Natural chemicals found in plant matter that are toxic to plants or animals eventually degrade, and composting accelerates this decomposition process. Just because a plant such as rhubarb contains oxalic acid, for example, that may be toxic to humans, does not mean that the compost made from this plant matter will be toxic to plants. In fact, the research shows that it is not.
Myth 7: Build your bin on soil so microbes can enter the pile
Most commercial compost operations work just fine on top of concrete and asphalt. The number of microbes that will enter the pile from beneath it is insignificant. Add microbes in the form of old compost as an inoculant when the compost ingredients are mixed instead.
Myth 8: Add earthworms from the garden to the compost pile
If the pile is just being started, the heat may kill the earthworms. Earthworms from the garden might escape the heat if they are lucky and start a new burrow in the soil beneath the pile. But garden worms actually do little to assist the composting process compared to their cousins, the redworms. Not all worm species are identical, and in fact, of the over 1,800 species of earthworms found around the world, only two species of redworms are used regularly to assist the composting process. The beneficial redworms must be acquired from a worm grower and added after the pile has cooled, and then the pile has to be kept properly moist to make them happy.
Myth 9: Composting is Nature’s way of managing dead organic material
Nature does not build piles; nature mulches in layers. Composting is a "pile making" behavior characteristic of humans which converts organic materials into dark crumbly stuff so that it can be converted back into a layer, as nature intended. Composting is perfectly "natural", but piles are not nature’s way of degrading organic materials into humus. Composting is an ingenious human response that speeds up the natural decomposition process.
Myth 10: Doing or adding ‘such and such’ accelerates composting
Composting can never be accelerated; it can only be delayed. There is an optimum rate of decomposition that occurs when moisture, air, temperature, and nutrients are properly balanced and blended. If any of the essential components to decomposition are out of balance, the decomposition rate can be slowed. Since most people practice passive composting where organic materials just sit there, they think that composting takes years since it takes years for them. When they add moisture, mix ingredients, inoculate, retain heat, or do other activities that optimize the decomposition process, they naturally think that they have "sped up" the composting process. In fact, they have merely eliminated some of the delays. Composting rates may be relative from batch to batch, and some materials decompose more quickly than others. But there is in fact an optimum and ideal rate of composting that remains constant.
Keep in mind however, that humus produced from slow decomposition is just as beneficial for the soil as organic matter produced from the best of the hot
composting piles. Optimum rate composting allows the individual to process more material in the same space than delayed rate composting. It is your
decision and management skills that determine how quickly or slowly your compost is finished. Fast is not necessarily better.
Myth 11: Don’t add grass clippings because they contain herbicides
Grass clippings, even those treated with over-the-counter herbicides are safe to use for composting. Even without composting, the common household
herbicide 2,4-D is not significantly toxic to established plants after a week or so. Fresh clippings may retain some high levels of herbicide if they are used as a mulch. Compost, however, is rarely used until six months or a year after it is made. I have seen no studies showing that 2,4-D is persistent in the soil and on foliage for this length of time. I have reviewed numerous studies that show that 2,4-D degrades 87% within ten weeks in the compost pile. Other studies show them to be non-detectable after six months.
Myth 12: Don’t add paper, it contains toxic metals and inks
Paper products are safe to use in the compost pile. Heavy metals such as nickel, lead and cadmium are a problem in some industrial sludges, and lead used to be a problem in paper. But lead-printing plates were banned in North America over twenty years ago and lead is now at background levels in paper. Numerous tests have been conducted of various grades of mixed paper and the heavy metal levels are virtually the same as a variety of other ingredients. All plant matter contains trace amounts of heavy metals, and the EPA has set limits regarding the concentrations of a variety of metals that can be safely used in the soil. Paper products are well below these levels.
Regarding the inks themselves, the amount of hydrocarbons in the ink is insignificant, and the composting process is widely used as a technique by bioremediation specialists for degrading a variety of hydrocarbons, even gasoline, oil and diesel. The tiny amount of hydrocarbon solvents in paper will be quickly degraded in the compost pile. Soy inks are used not to reduce toxicity of the paper as much as to promote the use of renewable
resources over non-renewable fossil fuels. Don’t add hydrocarbon-contaminated soils or motor oil to the composting process. Bioremediation requires extensive testing and rigidly controlled processes.
Myth 13: Black dirt or topsoil is better than compost
Organic, fertile soils are living ecosystems that took thousands of years to become fertile by Nature’s process of annual mulching. When people move into a new frontier, the soils are rich in organic matter and are highly fertile. Once depleted, however, a process that can occur in a few years or generations, it will take thousands of years to enrich the topsoil with organic matter again. We can accelerate this process of building up soil fertility by tilling in compost in a single afternoon, creating living soils in a fraction of the time. There is no point purchasing "black dirt" that was mined off someone else’s depleted land; it is probably just as worthless as the soil you are trying to enrich. It is better to enrich the soil you already have with compost or remove the old soil and replace it with soil mixed with compost.
The soil is not just a bunch of mineral-stuff to hold roots so that we can feed it hydroponically with chemicals. If it is to be alive, it must have food for the organisms that live in the soil. This food is either compost or humus. A virgin prairie or forest soil can have as much as 7% organic matter. Most of our farm soils have between 1% to 4% organic matter, not a high enough percentage to support a dynamic soil ecosystem. Most soils in modern subdivisions have only an inch of topsoil on top of poor subsoils that have 0% to 1% organic matter. It is a crime, in my opinion, to remove the topsoil and leave such poor soils for the householder to try and grow trees, shrubs, lawn or a garden. But this disadvantage can be corrected with a proper application of compost-enriched soils, bringing even the worst subsoil up to high fertility standards.