Compost is\nheralded as the fix-all black gold of the horticulture world. Not only can it\nimprove any soil type, but it is also free to make and extremely cheap to buy.\nIt reduces waste, improves soil health, and can even give you tastier veggies\nfrom the garden.\n\n\n\nSo, what is this\nmagic elixir, and how do we make it?\n\n\n\nIn order to\nunderstand how and where your compost will be most effective, you have to\nunderstand what compost truly is, and how it interacts with your soil. \n\n\n\nCompost is more than the sum of its parts; it\u2019s an ecosystem. Understanding each part of the system - and the interdependent web of life within - is the foundation for building a healthy compost pile.\n\n\n\n How Compost Is Made: The Basics\n\n\n\nCompost is the matured, humus-like remains of organic material that have been broken down through controlled aerobic biodegradation. (source) \n\n\n\nSo, what does\nthat mean?\n\n\n\nBasically, compost is the result of human intervention in the natural process of decomposition. Plant material will decompose on its own under most circumstances, but controlling the process yields the best possible product for soil improvement.\n\n\n\nIngredients\n\n\n\nTo build a basic compost pile, you\nneed to start with the right ingredients.\n\n\n\nComposting is a series of interactions between nitrogen and carbon. So, compost ingredients are measured in terms of nitrogen-heavy and carbon-heavy material.\n\n\n\nNitrogen-heavy (green) materials are fresh, flexible, moist plant waste. \n\n\n\n\n\n\n\nExamples of green ingredients are:\n\n\n\nGrass clippingsFruit peelsVegetable scrapsPulled weedsHerbaceous pruningsManure\n\n\n\nCarbon-heavy (brown) materials are old, rigid, dry plant waste. Examples of brown ingredients are:\n\n\n\nFallen leavesHardwood pruningsTwigsPaperCardboard\n\n\n\n\n\n\n\nIn general, the recommended ratio of carbon to nitrogen by volume is 2:1, with a brown layer on the top and bottom. Brown ingredients tend to be bulkier, and therefore help with the airflow. \n\n\n\nGreen ingredients are more compact and help retain moisture. Too much of either ingredient will result in a pile unable to maintain the correct balance of oxygen and water.\n\n\n\nMixture\n\n\n\nDecomposition can\nhappen in a number of environments, but the\nspecific process needed for healthy compost is aerobic\nbiodegradation, which means controlling the ratio of oxygen to\nwater within the pile.\n\n\n\nTo maintain aerobic conditions, you must have oxygen. A lack of oxygen results in anaerobic conditions and this will greatly reduce the quality of your finished compost. \n\n\n\nTo maintain biodegradation, you must have water. A\nlack of moisture results in the death of microorganisms that break down\nmaterials into humus.\n\n\n\nIn general, the recommended ratio of air to water is 1:1, which is roughly the moisture content of a damp sponge. This ratio begins with a balance of bulky and fine ingredients but is maintained by wetting and turning the pile.\n\n\n\nAs the pile begins to break down, it loses volume. The green material will lose water content and the\npile will shrink. This loss of mass helps to hold moisture in the center of the\npile. Moisture allows microorganisms to move and eat, which is the majority of\nthe decomposition process. \n\n\n\nHowever, if the pile is too compact, air will not be able to move through the center, which will kill off aerobic microbes and encourage the growth of anaerobic microbes. Some anaerobic activity is necessary to break down difficult plant material, but an overabundance will kill aerobic microbes and result in a lot of useless, potentially toxic waste.\n\n\n\nIf the pile is\ntoo loose, there will be a lack of moisture in the center, which will kill off\naerobic activity and halt decomposition. Large sticks and twigs, or piles that\nare too small, can contribute to lack of moisture. Use a chipper to break down\nbulky materials into more manageable pieces.\n\n\n\nTurn the pile about once per week to help reintroduce oxygen and pull new material into the center to be broken down. This will help avoid anaerobic conditions and will allow you to monitor moisture content. You may need to wet the pile with a hose to keep it damp.\n\n\n\nComposting Process\n\n\n\nUnder ideal conditions, the composting process only takes a few months. A compost thermometer will help you monitor the process to keep the pile active.\n\n\n\nAs compost breaks down, it goes through three phases. Initially, the pile heats up as decomposition begins. Once the center is hot, different microbes take over and break down the material. As it breaks down, the food source for those microbes disappears, and they die off. This is signaled by a drop in temperature, which is your sign to turn the pile.\n\n\n\nHeat is a key component of active compost.\n\n\n\nFolding new\nmaterial into the center will introduce new food for microbes. The process\nbegins again as the pile heats up, uses up the new material, and cools off. If\nthe pile is turned as it cools, the time between these phases is reduced, and\nthe compost will finish in 6-8 weeks.\n\n\n\nAllowing more\ntime in between phases will not harm the compost, but it will extend the amount of time needed for a finished product. Once\nthe pile cools, it transitions from active to passive, and it must be turned\nand moistened to return to an active state of decomposition.\n\n\n\nAfter 5-7\nrotations, most of the material will be used up, and temperature fluctuations\nwill even out. This is the sign that your compost is nearly finished, and is\nready for the maturation stage.\n\n\n\nMaturity\n\n\n\nCompost is not\ntruly finished until it has cured. If you turn your pile, and the internal\ntemperature remains close to the ambient temperature, it is in the maturation\nstage. \n\n\n\nMaturation is an important, but often overlooked, stage of composting. Although the temperature does not change much, many chemical processes continue to take place. These chemical reactions are transforming complex compounds into forms plants can use. \n\n\n\nIf this stage is skipped, and compost is used without curing, it will tie up nutrients in the soil to finish decomposing. This will result in a temporary decrease in nutrient availability for plants and can do more harm than good as a soil amendment. \n\n\n\nDepending on the amount of decomposition that still needs to take place, the negative effects of using young, or hot, compost can last from a few weeks up to two years.\n\n\n\nWhen is compost ready? Compost is mature when the temperature remains constant after turning, and there is no remaining recognizable organic material. \n\n\n\nMature compost is\ndark, crumbly, and has an earthy odor. Compost with remnants of leaves,\nvegetable scraps, twigs, or other ingredients should be turned, moistened, and\nallowed to continue decomposing.\n\n\n\nComposted manure\nwill no longer smell like manure if it is aged properly. If there is still an\nodor of manure, it will cause nitrogen burn if it is applied to the soil.\n\n\n\nFinished compost can be used as a soil amendment, fertilizer, mulch, topdressing, seed starter, and container mix. Each application will require a slightly different finished product. \n\n\n\nSeed starter may require sifting, where mulch should be bulky. A topdressing can be somewhat young, but a fertilizer should be fully matured. \n\n\n\nCompost improves the soil on a chemical, physical, and biological level. It can be modified to improve certain soil properties, such as nutrition, pH, and structure. \n\n\n\nUnderstanding the true finished nature of compost, and the processes that influence it is crucial to creating or purchasing a product that will specifically address your needs.\n\n\n\nNow that we\u2019ve\ncovered the basics of the composting process, it\u2019s time to explore the science\nbehind the scenes.\n\n\n\n\n\n\n\nHow Compost Is Made: The Details\n\n\n\nIf you\u2019ve made\nyour own compost before, chances are we haven\u2019t told you anything you didn\u2019t\nalready know. There are tons of books, articles, and videos explaining how\nto build a basic compost pile, and how\nto use the finished product.\n\n\n\nThere\u2019s plenty of information out there about the how of composting. Now, we\u2019re going to explore the why behind it all.\n\n\n\nComposting Ingredients (Organic Materials)\n\n\n\nCompost\ningredients are classified as either green or brown. Green ingredients are\nnitrogen-heavy, and brown ingredients are carbon-heavy. Finding the right ratio\nbetween green and brown ingredients helps compost decompose quickly and\nefficiently.\n\n\n\nBut, why are nitrogen and carbon the key ingredients? All living things, including \u201cgreen\u201d ingredients, are full of carbon. Nitrogen is only one of the three most crucial vitamins for plant growth. So, why do we single out nitrogen?\n\n\n\nNitrogen\n\n\n\nNitrogen is the most important vitamin for plant growth. It is the main component in chlorophyll, which is the mechanism that allows plants to transform carbon dioxide and water into sugar. Nitrogen is also a key ingredient in amino acids. \n\n\n\nWithout nitrogen,\nplants would have no energy for growth, and no building blocks to grow with. \n\n\n\nBut, what is\nnitrogen\u2019s role in compost?\n\n\n\nCompost is one large digestive system. Nitrogen is one of the two main foods that are taken in, and thousands\nof different organisms produce enzymes to digest this food and turn it into\nsimple compounds. \n\n\n\nIn very simple terms, compost is microbe poop. And nitrogen is microbe food.\n\n\n\nProteins break down into amino acids, which then break down into inorganic ions like ammonium (NH\u2084\u207a) and nitrate (NO\u2083\u207b). These ions are water-soluble, and can be taken up by plant roots and used to rebuild amino acids, which are then used to form proteins. \n\n\n\nMicrobes use nitrogen to grow and reproduce, and their rapid growth is responsible for the heat generated at the\ncenter of the compost pile. As microbes begin to feed on nitrogen, they\nmultiply exponentially and consume the available nitrogen at the center of the\npile where moisture is ideal.\n\n\n\nTheir activity is so voracious that they heat the pile to the point where they kill themselves off, while simultaneously eating themselves out of food. This intense heat kills off many microbes, while the rest starve for lack of nitrogen. \n\n\n\nThe pile begins to cool, and this is the signal that it needs to be turned. As new nitrogen is incorporated into the center of the pile, the microbial population begins rapid regrowth, and the process repeats.\n\n\n\nMost nitrogen in compost is organic, meaning the majority of nitrogen is not available for immediate use. Nitrification is the process of organic nitrogen being broken down into ammonium and nitrate. This process will continue for years after the compost is incorporated into the soil, and is one of the reasons compost is an excellent fertilizer.\n\n\n\nMature compost only releases a small amount of available nitrogen and continues to release nitrogen at a slow, consistent rate. Many synthetic fertilizers are high in immediately-available nitrogen, which encourages rapid, unsustainable growth, and quickly leaches through the soil if it is not used.\n\n\n\nNitrification releases ammonia and other harmful substances. In a compost pile, this will off-gas without doing any damage. However, immature compost will release these substances into the soil, and it can cause plants to dehydrate and wither. \n\n\n\nThis is why it is especially important to allow high-nitrogen compost piles to mature completely before use. Composting piles of grass clippings or manure will take longer to cure, and may need to be incorporated into fallow ground.\n\n\n\nCarbon\n\n\n\nCarbon is\nfundamental to life. Plants are nearly half carbon, and while there\nis no lack of carbon for plants to use as fuel, an improper balance in a\ncompost pile will create problems.\n\n\n\nMicrobes are 50% carbon, and they also consume carbon as their prime energy source. \n\n\n\nMost microbes have a carbon to nitrogen ratio of about 6:1, but the demands of decomposing large amounts of organic material require a much higher carbon content. \n\n\n\nIf there is not enough carbon in a compost pile, microbes will feed primarily on nitrogen and break it down too quickly. This will result in large amounts of ammonia gas, which both smells terrible and lowers nitrogen content.If there is too much carbon, microbes will not have enough nitrogen for rapid reproduction, and decomposition will occur at a much slower, cooler rate. Heat is a primary component for breaking down tough plant fibers, so excess carbon may result in organic material that takes years to fully decompose.\n\n\n\nCarbon is mostly lost to the atmosphere as compost breaks down. Finished compost will have a carbon to nitrogen ratio of about 10:1, but a beginning ratio of 30:1 is needed for proper decomposition. As microbes break down plant material, 67% of carbon is released into the atmosphere as carbon dioxide, while the free nitrogen is then used as an energy source for other organisms.\n\n\n\nInvertebrates play an important role in breaking down carbon-rich materials. Tough, fibrous plant tissue can require multiple cycles of decomposition in order to break down into fundamental elements. Food webs including slugs, snails, sowbugs, earwigs, beetles, ants, and other organisms. These organisms break down larger, tougher elements into smaller components for microbes to digest. \n\n\n\nParticle size can have a substantial effect on the availability of carbon. Small particles, like sawdust, has a large surface area and therefore more available carbon. The same wood source could be chipped but would have far less available carbon by volume. \n\n\n\nMixture\n\n\n\n\n\n\n\nUnderstanding C:N (The Carbon To Nitrogen Ratio)\n\n\n\nPerhaps one of\nthe more confusing instructions for building a compost pile is the carbon to\nnitrogen ratio.\n\n\n\nSome websites will claim that a good ratio is about two parts carbon to one part nitrogen. Other sources seem to say the ideal ratio is more like 30:1. Still, others say it doesn\u2019t matter as long as the pile smells fine and breaks down in a reasonable amount of time.\n\n\n\nAll of these\nclaims are true. Making sense of them lies in understanding the terminology.\n\n\n\nAll plant material is much higher in carbon than\nnitrogen. Even green, nitrogen-rich compost\ningredients are far higher in carbon than nitrogen. To say a compost ingredient\nis \u201cgreen\u201d is to say the carbon to nitrogen (C:N) ratio is lower than other\nplant materials.\n\n\n\nFor instance, vegetable waste has a C:N ratio of about 18:1 (source). It is far higher in carbon content than nitrogen, but it is one of the most nitrogen-dense, \u201cgreen\u201d compost ingredients you can find. \n\n\n\nOn the other hand, wood chips can have a C:N ratio of 400:1 (source), making them a \u201cbrown\u201d compost ingredient due to large amounts of carbon and very low nitrogen content. However, all plant material will contain substantially more carbon than nitrogen.\n\n\n\nThe C:N ratio is referring to the chemical properties of plant material. The ratio of carbon content to nitrogen content needed in a compost pile is roughly 30:1 for most applications.\n\n\n\nWhen sources say to use two parts brown material to one part green material, they are referring to volume, not chemistry. \n\n\n\nRoughly speaking, you should use two parts carbon-heavy material by volume to one part nitrogen-heavy material by volume.\n\n\n\nEach brown layer should be about 4\u201d thick, while each green layer should be about 2\u201d thick. However, this does not mean you will end up with a 30:1 C:N ratio by chemical makeup. \n\n\n\nA compost pile made of grass clippings and straw will have a vastly different C:N ratio than one made of manure and wood chips, even if the layers are equal in volume.\n\n\n\nAnd this is why\nsome sources say not to worry too much about the ratio. Unless you are going to\nheavily research your ingredients and weigh them for an accurate C:N ratio,\nyou\u2019re basically guessing and hoping it works out. This is why being able to\nrecognize an imbalance once decomposition begins is important. \n\n\n\nMixtures too high in carbon will be cooler and will not lose much volume. \n\n\n\nIf you have built a pile and the temperature does not fluctuate much in the first week, you may need to add material with a lower C:N ratio, like grass clippings.\n\n\n\nMixtures too high in nitrogen will be very hot and smell like ammonia. \n\n\n\nIf your pile loses a large amount of volume and smells like garbage, you may need to mix in material with a higher C:N ratio, like wood chips or dead leaves.\n\n\n\nTo maintain active decomposition, begin with a pile that is a 4\u2019 cube of ingredients. This will allow the center of the pile to retain heat and moisture. \n\n\n\nSmaller piles will have much smaller centers of decomposition and may take longer to break down. \n\n\n\nLarger piles can decompose properly if they are built in rows, but managing them can be difficult without large equipment to turn and move them.\n\n\n\nOxygen\n\n\n\nWithout oxygen,\npiles of plant waste would be a slimy, stinky mess. Almost all living organisms\nthat break down organic material require oxygen to live and reproduce. \n\n\n\nAs microbes break\ndown complex organic materials, they breathe in oxygen and breathe out carbon\ndioxide. This helps even out the C:N ratio, and also keeps the pile in a state\nof aerobic biodegradation.\n\n\n\nActive compost piles are breathing. As microbes use oxygen to break down other materials, they pull air through the pile. \n\n\n\nBreaking down nitrogen creates heat, and as they expel carbon dioxide, the warm air pushes up through the top of the pile. This continual inhale of oxygen and exhale of carbon dioxide creates airflow through a pile with balanced particle sizes. \n\n\n\nThis continued breathing keeps oxygen coming in to fuel the microbial activity. If oxygen is unable to move into the pile, aerobic microbes suffocate and die.\n\n\n\nAnaerobic microbes take over and begin a different decomposition process. Plant material is still broken down, but the waste material can be full of toxic substances that make the compost unusable.\n\n\n\nHowever, if the\npile is agitated, and oxygen is reintroduced, anaerobic microbes die off, and\nnew aerobic microbial activity breaks down the harmful waste material.\n\n\n\nThe key to healthy respiration is a mixture of large and small particle sizes. Dense, green materials like grass clippings can mat together and restrict airflow. Bulky, brown materials can allow too much oxygen flow which causes water to evaporate and dry out the aerobic microbes. \n\n\n\nA mixture of particle sizes will help respiration continue at an even rate, along with the consistent turning of the pile.\n\n\n\nAnaerobic decomposition can result in acidic compost. Most finished compost product has a pH close to neutral (7). Anaerobic activity produces harmful waste in the form of acids, which lowers the pH to an almost unusable level of 4.5. \n\n\n\nAs the pile becomes more acidic, microbial activity is limited even more. This can be reversed by turning the pile, and the pH will rise with healthy, aerobic decomposition.\n\n\n\nWater\n\n\n\nMoisture content influences all aspects of decomposition. Many microbes live in films of water that coat the particles within a compost pile. Other microbes live in tiny air pockets between these particles. Still, other organisms tunnel through particles but die as the particles dry out.\n\n\n\nLike C:N ratio, air to water ratio is a rough estimate.\nGenerally speaking, the spaces between particles should be 50\/50 air to water,\nalthough anything from 40\/60 to 60\/40 is acceptable.\n\n\n\nMost piles,\nunless covered or in a protected microclimate, will dry out on the top and\nsides. This is normal, and does not inhibit microbial activity as long as the\ncenter of the pile can retain moisture. Many compost piles have an ecosystem in\nthe center that is independent of the surrounding environment. \n\n\n\nTo determine healthy moisture content, pick up a handful of material from the center of the pile and squeeze it. It should be damp, but only let out a few drops of water. Too much and you risk anaerobic activity. Too little, and decomposition will slow or stop completely.\n\n\n\nYou may need to water your pile to maintain healthy moisture content. As the pile decomposes and expels warm carbon dioxide, water vapor is lost and moisture decreases.\n\n\n\nWetting down the pile during active decomposition will cause the temperature to drop and decomposition will halt. As long as your pile is not in a hot, windy location, it should only need supplemental water when you turn it, and this will not interfere with the composting phases. \n\n\n\nIf your compost pile is drying out quickly after turning, there may be too much carbon. Try adding some green material and checking moisture content after a few days.\n\n\n\nThe Composting Process\n\n\n\nIf a pile has\nbeen built with the proper ingredients and structure, healthy decomposition can\nbegin. \n\n\n\nTime\n\n\n\nThe success of a\ncompost pile is identified by the phases it will cycle through. \n\n\n\nThe active phase of composting is a repeating cycle of mesophilic and thermophilic decomposition (source). Mesophilic bacteria begin to colonize the compost pile as conditions in the center are able to support rapid growth. \n\n\n\nFungi, bacteria, actinomycetes, and protozoa begin to consume organic material when moisture and oxygen requirements are met. This rapid growth is signaled by a spike in the internal temperature, which consequently kills off the mesophilic organisms.\n\n\n\nAs the mesophilic\nphase ends, the thermophilic phase takes over. Thermophilic organisms multiply\nexponentially, creating an intense heat that can kill pathogens and weed seeds.\nThis heat can also break down tough plant fibers and phytotoxic compounds. \n\n\n\nAs thermophilic\norganisms run out of organic material to consume, they die off and the\nmesophilic microorganisms reemerge. The pile cools, and this is the signal to\nmix or turn the compost. This will add new plant material to the center of the\npile, and the cycle will repeat.\n\n\n\nDuring the active phase, the internal temperature will fluctuate between 60\u00ba and 160\u00ba. When the temperature drops to 100\u00ba, it is time to turn the pile. The temperature will drop, then climb, then fall back to 100\u00ba as the mesophilic and thermophilic phases cycle through. \n\n\n\nIf you turn the pile and the temperature remains constant, the pile has moved from the active phase to the curing phase. The curing process is a steady decline in mesophilic decomposition, followed by a few months of sitting and maturing. \n\n\n\nThis maturation phase is often overlooked, but it is the difference between a helpful amendment and an organic herbicide. Immature compost can release organic acids into the soil, contain large amounts of salt, or severely lower pH.\n\n\n\nAs compost\nmatures, chemical compounds are broken down into final forms that are able to\nbe used by plants. Harmful gasses are safely expelled, salts can leach out, and\npH will stabilize. \n\n\n\nUnder ideal\nconditions, compost can be ready to use in only three months. Home compost\npiles may take as long as two years, however, if the active phase is not\nconsistently maintained.\n\n\n\nMaturity\n\n\n\nAs stated above, if all the requirements are met for healthy biodegradation, compost will be ready to use after a few months. \n\n\n\nMature, cured\ncompost can be used for a number of applications. The benefits of compost are a\ndirect result of the structure and composition of the finished product.\n\n\n\nHumus\n\n\n\nThe term humus is contradictory in soil studies.\nIn fact, many in the field claim humus does not even exist. \n\n\n\nTraditionally,\nhumus is identified as the skeleton of decomposed organic material. Mature\ncompost will continue to break down once it is incorporated into the soil. In a\nfew short years, the bulk of compost is almost completely broken down and\nreabsorbed by plant roots.\n\n\n\nHowever, a small percentage of decomposed material will remain as a stable fixture in the soil. It will resist future decomposition and will retain its structure. It is negatively charged, which helps it hold on to ions that would otherwise be lost through leaching. It also helps the porosity of the soil by retaining water while allowing excess moisture to drain freely.\n\n\n\nThis material has\nbeen referred to in the past as humus, and it is a major benefit to adding\ncompost to your soil.\n\n\n\nUnfortunately, humus is not a term that is well\nunderstood, accepted, or regulated. Humus (if it exists) makes up only 2-3% of\nthe bulk of compost, and it is nearly impossible to separate out into a solo\nproduct. \n\n\n\nThis does not\nstop manufacturers from labeling their compost as \u201chumus\u201d, and charging more\nfor their products. There is no quick fix for adding large amounts of humus to\nyour soil, and it may be harmful even if it were possible.\n\n\n\nThe only way to build up the humus content of the soil is to add cured compost on a consistent basis. \n\n\n\nNutrient Profile\n\n\n\nAs organic\nmaterial decomposes, complex compounds are broken down into fundamental\nelements. These elements are able to be utilized by plants, which then build\nthem back into complex structures. \n\n\n\nMost of these\nfundamental compounds are the vitamins and minerals that plants need in order\nto grow and reproduce. The composting process breaks down these nutrients into\nplant-available forms, which is why it is often used as an organic fertilizer.\n\n\n\nThere is no way\nto know the nutrient profile of your compost without ordering a compost\nanalysis from a lab. However, there is a generally-accepted range that most\nhealthy compost products should fall within that can give you an idea of what\nyou are putting back into your soil. \n\n\n\n\n\n\n\nRegardless of the\nquantity of nutrients in compost, they will only be available if the pH is\nclose to neutral. If pH is too acidic or basic, nutrients can become chemically\ntied up and unable to be used by plant roots. \n\n\n\nSome compost\ningredients can intentionally alter the pH, like pine needles and coffee\ngrounds. However, these ingredients would have to be in high quantities to make\nmuch of a difference. Plus, altering the pH of a pile can throw off the entire\ndecomposition process and produce a low-quality product. \n\n\n\nIt is better to\ncreate a healthy, balanced compost pile for your lawn and garden, and then use\nother amendments to correct pH levels. Adding gypsum or lime to your soil gives\nyou much more control over final pH levels than trying to manipulate the pH of\na compost pile.\n\n\n\nMature compost acts as a mild, slow-release fertilizer for many years. Most of the nitrogen and other nutrients are still bound in unusable forms even once the compost has cured. Once the compost is incorporated into your soil, it will continue to slowly break down and release those elements over time. \n\n\n\nThe nutritional benefits of one compost application can last over a decade depending on the plants that are growing in the soil.\n\n\n\nThe key to\nnutritional benefits from compost is consistent applications. One application\ncan help some, but yearly applications will build upon themselves and add a\nsubstantial amount of slow-release nutrition. \n\n\n\nThis gradual\nrelease of nutrients can also harm soil depending on the original soil profile.\nThe ability to hold onto nutrients is helpful for nitrogen and other nutrients\nthat can easily leach out of the soil. However, nutrients like phosphorus will\nbind with the soil particles and build up over continued compost applications.\n\n\n\nPhosphorus is necessary for root growth, but in high quantities it becomes toxic. Excess phosphorus can prevent nitrogen from being absorbed by plants, and can tie up other nutrients in the soil. Because phosphorus is so difficult to remove from the soil, it is important to continue yearly soil tests to monitor nutrient levels. \n\n\n\nPhosphorus buildup is evidenced by stunted plant growth and an overall decline in health. A soil test can confirm toxicity.\n\n\n\nYou can remove phosphorus with expensive chemical treatments, but a more reasonable option for most gardeners is to cease compost and fertilizer treatments and plant a cover crop of nitrogen-fixing plants like peas. These can bring nitrogen into the soil while using phosphorus to grow, which can help even out the nutrient profile.\n\n\n\nMonitor nutrient\nlevels annually, and experiment with a variety of compost ingredients. Manure\nis generally responsible for high phosphorus content, so try using other\nnitrogen-rich ingredients like grass clippings.\n\n\n\nUses\n\n\n\nCompost has a\nwide range of uses depending on your growing needs. The general properties of\ncompost as a fertilizer is what makes it so versatile. \n\n\n\nCompost can retain nutrients and make them available on a slow, consistent basis. This makes them an ideal soil amendment or fertilizer. For bare soil, mix in a \u00bc\u201d-\u00bd\u201d layer of compost into the topsoil before planting. \n\n\n\nFor vegetable gardens, spread a layer on top of an empty bed, and gently rake it in. Tilling each year will destroy the structural benefits of organic matter and create unhealthy soil conditions in your garden beds.\n\n\n\nCompost will improve the structure of any soil. It will add porosity and help drainage in clay soils, and it will add bulk and help water retention in sandy soils. \n\n\n\nFor established lawns and landscapes, apply compost as a topdressing to build up a healthy topsoil layer. \n\n\n\nLawns need about \u00bc\u201d of compost spread on top and watered in. Trees and shrubs can take a much heavier layer of 1\u201d-2\u201d out to the drip line, and this will act as a topdressing and mulch.\n\n\n\nWith a little preparation, compost makes a cheap seed starter and soil-mix ingredient. Sift compost by placing a compost screen over a bucket or wheelbarrow. \n\n\n\nThe screen should be fine enough to catch small rocks and grubs, but large enough to allow some bulk to fall through. Window screens are too fine for compost. \n\n\n\nSifting cured compost will result in a uniform, aerated mixture that will hold up well as a seed starter or in a raised bed mixture.\n\n\n\nCompost: Enhancements\n\n\n\nKnowing the why behind composting helps in\nunderstanding the basic process. \n\n\n\nHowever, knowing\nthe rules is only half the equation for making high-quality compost. Once you\nlearn the rules, you can bend them, and customize your compost for your\nparticular needs.\n\n\n\nBins\n\n\n\nMany compost\npiles are just fine as a free pile on the ground, but there are a number of\nreasons to build a compost bin.\n\n\n\nThere are a number of advantages to building a compost bin:\n\n\n\nConserving spaceAestheticsOrganizationEasy-access for machinery and\ntoolsDeterring wildlifePromoting decomposition with small\npilesSpeeding up decompositionWorm compostingImproving aeration\n\n\n\nCompost piles can\nspread out and make a mess, especially when you turn them. Building a bin can\nhelp contain your pile and make it easier to aerate, mix, and move. \n\n\n\nSimple\ncontainment bins can be four corner posts with some chicken wire or wood scraps\nfor sides. Leave one side open for easy access.\n\n\n\nA four-sided compost bin with a gate can be used for a more aesthetic compost bin. Use non-treated wood or fencing, and put a gate on one side for access. Aeration is important for compost bins, so make sure the sides are able to allow airflow.\n\n\n\nChicken wire or chain-link fencing can help deter some wildlife from your pile, although using the proper ingredients is a far better solution. \n\n\n\nGenerally speaking, the only reason wildlife will be attracted to your compost pile is if you are using ingredients that don\u2019t belong. Meat, cooked food, bones, and other foods may decompose over time, but they are not suitable for a compost pile.\n\n\n\nFor composting in small spaces, you may need a micro-bin or micro-tumbler (like this one on Amazon) to aid decomposition and help retain heat and moisture. \n\n\n\nIdeally, compost piles should start as a 4\u2019 cubic pile. But, compost can be made in spaces as small as a soda bottle (source). If you\u2019re tight on space, or low on ingredients, try buying or building a micro-bin, and use small amounts of compost in potted plants.\n\n\n\nSome climates may require compost bins in order to maintain temperature and moisture. Extremely hot, cold, windy, dry, or wet climates may not allow the compost to break down successfully. Covering a pile can help retain moisture, or keep out excess water, but it can also prevent aeration. \n\n\n\nTry building a simple compost bin and use a tarp to cover the bin, while leaving space above the pile. Insert pipes into the pile for aeration, and take care to turn or mix it to prevent anaerobic conditions from forming.\n\n\n\nAnother option for extreme climates is a compost tumbler. This makes your compost pile mobile, which can help for small-scale use. One tumbler can make enough compost for a small vegetable garden or flower bed. \n\n\n\nClick here to browse and check the latest pricing on manufactured compost tumblers at Amazon.\n\n\n\nComposting With Worms\n\n\n\n\n\n\n\nIf you want a high-nutrient content fertilizer, consider building or purchasing a worm bin. Red wiggler worms will break down organic material into nutrient-dense castings, which can be used in small quantities in specific applications. \n\n\n\nWorms need a brown material for bedding, like shredded newspaper or cardboard, and they are fed green material as they grow. If it is maintained properly, a worm bin does not smell and can be stored under the sink or in a garage for easy access.\n\n\n\nAnd yes, you can absolutely compost those Amazon boxes. Click here to read more.\n\n\n\nWorm bins, or vermicomposting, follow different rules than a typical compost pile. It is technically a form of composting, but all of the chemical processes happen within the digestive system of the worm. \n\n\n\nThe bin should not heat up or fluctuate in temperature, and there is no need to turn the material because the worms create tunnels for aeration as they eat.\n\n\n\nComposting Ingredients\n\n\n\nCompost can be\nslightly altered depending on the types of ingredients, and the ratio of carbon\nto nitrogen. \n\n\n\nThe nutrient content is most easily manipulated by the addition of manure. Horse, cow, and chicken manures have high nitrogen content and few pathogens that can affect humans. \n\n\n\nComposting manure can yield a product higher in nitrogen and phosphorus, and is more potent as fertilizer than composted grass clippings or vegetable scraps. However, unless you are planting heavy feeders on a consistent basis, composted manure can cause phosphorus toxicity if it is applied annually.\n\n\n\nAltering the pH content can be a little more difficult, but it is possible if you have the right ingredients. \n\n\n\nPine needles, coffee grounds, and oak leaves will lower the pH of compost until it has fully decomposed. \n\n\n\nIt can also cause unfavorable conditions for some microorganisms, and therefore a pile with lower pH can be harder to maintain. The effects on pH will last until the organic material has fully decomposed, which can take a few years once it is incorporated into the soil. \n\n\n\nCompost Amendments And Accelerators\n\n\n\nThere are many advertised products that are supposed to accelerate, manipulate, and activate your compost pile. Most are completely useless and downright harmful to the composting process. \n\n\n\nThe terms used\nfor compost amendments are largely unregulated and poorly defined. Good compost\nis a product of a natural process that takes time. Accelerating or manipulating\nit chemically is not necessary and can inhibit the microbial activity that is\nworking hard to give you a good product.\n\n\n\nThere are only\ntwo situations where a compost amendment is helpful.\n\n\n\nSoil\n\n\n\nMicrobes live on everything, and your compost will be full of them. Many migrate up from the soil and into the organic material as they begin to break it down. \n\n\n\nIf you are building compost piles on slabs of concrete, asphalt, or other foundations that do not have access to soil, you may want to throw a few handfuls of soil in with your ingredients. It is likely unnecessary, but it can help get the process started, and it\u2019s free.\n\n\n\nNitrogen\n\n\n\nIf you are composting lots of brown material, you may need a nitrogen amendment to maintain healthy decomposition within the pile. \n\n\n\nLarge piles of leaves, twigs, and paper need nitrogen for the chemical process of biodegradation, but you may not have access to the necessary quantities of green material. \n\n\n\nYou can buy urea, blood meal, and other nitrogen-heavy amendments to make up for the lack of green ingredients, but you will need much less by volume than a traditional layer of weeds or veggie scraps. \n\n\n\nYou will lose the benefits of water and heat retention that wet, dense, nitrogen-heavy organic material provides, but these amendments will at least help the decomposition process begin, and it will speed up the decomposition of tougher materials.\n\n\n\nWhile it is possible to manipulate certain properties of compost, it is always better to allow the process to happen naturally and in its own time. Amendments, different styles of bins, and altering ingredients should only be done in response to problems, and not in an effort to make compost do a job it was not intended to do. \n\n\n\nThere are a vast amount of soil amendments and conditioners that are specifically formulated to influence certain soil properties, and they give you much more control over the desired outcome.\n\n\n\nIf you are adamant about using a compost accelerator, click here to read our top recommended brands.\n\n\n\nConclusion\n\n\n\nCompost is a complex, dynamic ecosystem that provides many long-term sustainable benefits for soil. Once you have an understanding of the why behind the how, you can recognize unhealthy situations and how to correct them. \n\n\n\nIt is also easier to recognize which soil issues compost can help fix, and which it may potentially aggravate.\n\n\n\nEven if you don\u2019t make your own, understanding how compost is made can help make purchasing decisions for certain applications. \n\n\n\nIt will also help you determine whether or not a certain product has been composted correctly, and may create issues in your soil.\n\n\n\nHowever, most\nimportantly, compost is as much an art as it is a science. We\u2019ve explained the\nscientific details to aid understanding, but once you get a feel for healthy\ncompost, you may find that bending or breaking a few rules gives you better\nresults. \n\n\n\nAre you building a compost pile? \n\n\n\nCheck out our other articles for information on how to build an active compost pile, common compost problems, and which foods should never make it into your compost bin.