\u2022 Compost is the best\nsource of organic matter and humus for the garden. It is so valuable that the\ncompost pile has been called the heart of the organic garden. <\/strong><\/p>\n\n\n\n \u2022 Compost is often the\nmain source of nutrients in a mature organic garden. These are securely held in\nthe form of microorganisms and organic matter and are slowly made available to\nplants as soil organisms break them down. <\/p>\n\n\n\n \u2022 Compost encourages a\nhealthy population of soil organisms, by providing food for them, as well as\nbeing full of living organisms itself. A teaspoonful of compost may contain 1\nbillion bacteria, 2500 protozoa, 300 feet of fungal hyphae and 150 nematodes. <\/p>\n\n\n\n \u2022 Composting gives you a\nsimple way to dispose of organic household and garden waste and turn it into\nuseful fertilizer. If you are ambitious it can even be used to dispose of human\nwaste.<\/p>\n\n\n\n \u2022 Compost suppresses a\nvariety of soil pathogens, including damping off (compost tea works also). <\/strong><\/p>\n\n\n\n \u2022 The composting process\nbreaks down toxins such as pesticides and can bind heavy metals to make them\nunavailable to plants. <\/p>\n\n\n\n Problems with compost<\/strong><\/p>\n\n\n\n \u2022 My biggest problem\nwith compost is that it takes work and foresight to make, which means I never\nhave enough of it. <\/strong><\/p>\n\n\n\n \u2022 Poorly made compost\nmay not have heated up enough to kill weed seeds. Spreading this kind of\ncompost on your beds can plant thousands of weed seeds. <\/p>\n\n\n\n \u2022 Poorly made piles may\nsmell bad and can attract scavengers such as flies raccoons and rats, which can\npresent public health problems. <\/strong><\/p>\n\n\n\n Composting as a means of\nrecycling<\/strong><\/p>\n\n\n\n In recent years we have\nbegun to realize the importance of recycling wastes, rather than discarding\nthem and composting is particularly useful in this regard. It allows you to\ntake materials that would otherwise end up in the landfill and convert them\ninto a valuable product. The most commonly composted household material is\nkitchen waste, but almost anything that once lived can be composted, so long as\nit hasn\u2019t been treated with (or mixed with) toxic chemicals.<\/p>\n\n\n\n Non-gardeners often imagine\nthat compost making must be a smelly affair. They assume that decaying\nvegetation, food scraps and manure must inevitably smell and attract flies and\nvermin. Actually there is a big difference between a well-made compost pile and\na heap of rotting garbage (throwing the daily accumulation of kitchen waste in\na heap out in the garden isn\u2019t composting. The compost pile doesn\u2019t attract\npests or smell very much. In fact composting is one of the best ways to dispose\nof this kind of material without having such problems.<\/p>\n\n\n\n How composting works<\/strong><\/strong><\/p>\n\n\n\n The workings of the compost\npile have been studied closely and are now pretty well understood. The process\nbegins when micro-organisms in the newly completed pile start to break down the\nmost easily digested materials, the simple sugars and starches (these can be\nbroken down by many organisms). The abundant food source causes a population\nexplosion and the respiration of billions of organisms in a feeding frenzy\ncauses the pile to heat up rapidly. As the pile heats up other organisms get to\nwork on the more resistant materials. Cellulose can only be broken down by a\nfew organisms (snails, termites and bacteria) that secrete the enzyme\ncellulase. This breaks cellulose down into simple sugars, organic acids and\ncarbon dioxide. Proteins are broken down into amino acids, then into ammonium,\nthen nitrates and (sometimes) then into ammonia gas (this is why some piles\nsmell strongly of ammonia). Lignin, waxes and resins are very decay resistant\nand require a sequence of organisms to break them down.<\/p>\n\n\n\n When the readily available\nfood has been consumed many of these organisms die and the ensuing reduction in\nrespiration causes the temperature in the pile to drop. As organisms die they\nin turn are broken down and release the nutrients they have accumulated. The\nstuff remaining at the end of the composting process contains a large\nproportion of humus, a stable form of organic matter that is very resistant to\ndecay.<\/p>\n\n\n\n During the fermentation\nprocess a lot of material in the heap is lost to volatilization. As much as\nthree quarters of the carbon in the pile may be released as carbon dioxide,\ncausing the C : N ratio of the pile to drop from around 30 : 1 to around 8 or\n12 : 1. Some nitrogen is also lost as ammonia, especially if the C : N ratio\nstarts out lower than 30 : 1 (the final C : N ratio will still be around 8 or\n12 : 1).<\/p>\n\n\n\n Compost temperature<\/strong>: While the compost pile is cool, (up to 50\u00b0F or 10\u00b0 C) it is said to be in the cryophilic\nstage and decomposition happens no faster than in the soil. As biological\nactivity increases, heat is generated faster than it can dissipate from the\nwell insulated mass of the pile, so it gradually heats up. When the interior of\nthe pile reaches 112\u00b0F (40\u00b0 C), the composting process enters the mesophyllic\nstage. Mesophyllic organisms are most efficient at higher temperatures, so\ndecomposition proceeds rapidly as it gets warmer. As the heat builds in the\ncenter of the pile it gets hotter and hotter, until these organisms either die\noff, or migrate to cooler areas. The thermophyllic stage is then reached and\nspecially adapted heat loving organisms take over (these can survive up to\n180\u00b0F (80\u00b0 C). Temperatures above 140\u00b0F (60\u00b0 C) are needed to kill pathogens,\nweed seeds and pernicious roots, but decomposition slows somewhat at such high\ntemperatures.<\/p>\n\n\n\n When most of the available\nnutrients are consumed the pile begins to cool down and mesophyllic organisms\ntake over again (some of these survived out at the cooler edges of the pile).\nThese keep on working as the pile cools, until the temperature gets low enough\nfor cryophilic organisms such as earthworms and actinomycetes to come in and\nfinish the job.<\/p>\n\n\n\n You might think that the\nhotter the pile gets, the better, but this isn\u2019t the case. You don\u2019t want it to\ngo much above 150\u00b0F. Very hot piles waste nutrients through volatilization, so\nthat 60% or more of the volume of the pile may disappear. You can cool a pile\ndown by turning it, adding soil, or by adding more carbonaceous material.<\/p>\n\n\n\n A compost pile doesn\u2019t heat\nup uniformly all the way through. The well insulated center gets the hottest\nand it gets progressively cooler towards the exterior, where it is easier for\nheat to escape. This is significant because it allows many organisms to avoid\nbeing killed in the intense heat of the center, by moving out to a zone more to\ntheir liking. As the pile cools they migrate back to the center. To ensure that\nall parts of the pile heat up sufficiently for good decomposition (and to kill\nweed seeds and pests), you should turn it at some point (see below).<\/p>\n\n\n\n Compost organisms<\/strong>: The\ncompost pile is alive <\/strong>with almost countless living\norganisms and these are responsible for the transformation that takes place.<\/p>\n\n\n\n The bacteria are the most\nimportant decomposing organisms and are active from the beginning of the\nprocess until the end (some even fix atmospheric nitrogen in the pile). Fungi\ngo to work on the pile within a week or so, but can only work in the cooler and\nwell-aerated outer layers. Actinomycetes also work on the well-aerated outer\nlayers and give the pile a grayish white color and a distinctive earthy smell.\nThey appear during the final stage of decomposition and their arrival indicates\nthe pile is almost finished. Other organisms are active during various stages,\nincluding earthworms (not the same as those which inhabit soil), beetles,\nprotozoa and woodlice.<\/p>\n\n\n\n Essential elements of composting<\/strong><\/p>\n\n\n\n When I first started\ngardening I piled plant debris in a wire cage, added some compost activator\ntablets and waited for it to become a compost pile. Needless to say it never\nhappened, because I didn\u2019t give the composting organisms what they needed. When\nyou build a pile you are not making compost, you are simply providing the\norganisms that do the work with food and shelter. Just think of your compost\npile as a big pile of tiny animals. Your aim is to keep these animals happy, so\nthey will multiply and do the necessary composting work for you. <\/p>\n\n\n\n Gathering materials<\/strong><\/p>\n\n\n\n You need a lot of material\nfor a compost pile, so you may need a place to store it until you have enough\n(it\u2019s not nearly as effective to build a pile in stages). Good organic\ngardeners are often good foragers, getting huge quantities of materials from a\nvariety of sources.<\/p>\n\n\n\n Particle size and texture<\/strong><\/p>\n\n\n\n The size of a particle\nlargely determines how quickly it can break down. The smaller the particle, the\ngreater its surface area in relation to volume and (theoretically) the faster\nit will break down (this is most important for quick piles). However if the\nparticles are too small they are easily compacted, which excludes air and so\nslows decomposition. The ideal particle size is about 1 – 2\u02dd.<\/p>\n\n\n\n You could chop larger\nmaterials (such as Brassica stems) with a machete or a sharp spade, or you\ncould lay them on your driveway to be run over by cars. Small woody material\ncan simply be used as a base layer under the pile. When the time comes to turn the pile it will be half\ndecayed and can be chopped more easily<\/p>\n\n\n\n Shredding<\/strong><\/p>\n\n\n\n You can hasten decomposition\nand produce finer compost by chipping stems, prunings and other bulky garden\nrefuse in a shredder. However it is not really necessary. I bought an almost\nnew electric shredder at a yard sale, but (like the first owner) I haven\u2019t\nreally used it for this.<\/p>\n\n\n\n Shredders can be useful for\nmaking very fine compost quickly, but this hardly justifies their cost. By\nreducing everything to a satisfying homogenous mass they fulfill an urge for\nneatness that some people will appreciate, but at some cost in noise, fuel,\nfrustration and money (you could buy quite a few hand tools for the price of a\nshredder).<\/p>\n\n\n\n Mixing<\/strong><\/p>\n\n\n\n Ideally the materials would\nbe completely homogenous throughout the pile, but in practice we usually make\nthe pile in thin layers of various materials, alternating nitrogenous materials\n(green matter, manure) with carbonaceous materials (straw, leaves and other\ndried plants) and the occasional thin layer of soil (for bacteria and\nminerals). We never have large masses of a single material, as this could slow\ndecomposition. A shredder can be used to mix the materials in the pile, by\nsimply alternating the materials you put through the shredder.<\/p>\n\n\n\n Moisture content<\/strong><\/p>\n\n\n\n Probably the most critical\nfactor in the whole composting process is having the right moisture content in\nthe pile. It it is too wet or too dry the composting organisms won\u2019t be happy\nand it simply won\u2019t work. Well made compost has the texture of a wrung out\nsponge, it\u2019s moist, but you can\u2019t squeeze water out of it.<\/p>\n\n\n\n Too dry<\/strong>: In dry California I\u2019ve seen many compost\npiles that weren\u2019t working because they had dried out too much. A pile must\ncontain 50 – 60 % water if it is to work well and if there is less than 45%\nwater the pile may not heat up at all. As you add materials to the pile make\nsure they contain as much moisture as they can hold. This is especially\nimportant for dry materials such as dry leaves or straw. In very dry climates\nyou may want to enclose the pile, to stop it losing too much moisture (though\nthis may reduce the amount of air it gets also). You should also put it in the\nshade.<\/p>\n\n\n\n Too wet<\/strong>: In cool\nwet weather you must make sure the compost pile doesn\u2019t get saturated with\nwater. Too much water means too little air and can result in smelly anaerobic\ndecomposition. Excess moisture can also result in the leaching of nutrients. <\/p>\n\n\n\n Carbon to nitrogen ratio<\/strong><\/p>\n\n\n\n The carbon to nitrogen ratio\nis a very important factor in successful composting, as you need to keep the\nmaterials in the pile in roughly the right proportions. High carbon materials\ninclude straw, sawdust, hay and dry leaves). High nitrogen materials include\ngreen leaves, food waste and manure. For a pile to work well there should be a\nbalance of approximately 25 – 30 parts carbon for every 1 part nitrogen. See\nthe chart of carbon to nitrogen (C : N) ratios for various common materials at\nthe end of this section.<\/p>\n\n\n\n Some gardeners prefer to\nmake piles with a slightly higher carbon to nitrogen ratio (35 : 1 or more) so\nthey won\u2019t heat up as rapidly, or get as hot (only up to about 90\u00b0F). They\nbelieve cooler piles are better as they don\u2019t lose so many nutrients through\nvolatilization. The drawback is that they may not get hot enough to kill all\nweed seeds, pernicious weed roots, or diseased plant material. Of course the\nsimple solution to this problem is to not put such stuff in the pile.<\/p>\n\n\n\n Composting isn\u2019t rocket\nscience and you don\u2019t have to be too obsessive in calculating the carbon to\nnitrogen ratio, so leave the scale and calculator indoors. Approximate is good\nenough. If there is a higher proportion of nitrogen the excess will simply be\ngiven off in the form of ammonia and wasted (you will be able to smell it). If\nthere is too much carbon the pile won\u2019t heat up as quickly, or get very hot. <\/p>\n\n\n\n The carbon to nitrogen ratio\nis often expressed as a single number and indicates the number of units of\ncarbon relative to one unit of nitrogen. For example a ratio of 30 would mean\nthere was 30 units of carbon to every one unit of nitrogen A high number (such as 400) means there is a\nlot of carbon relative to nitrogen and that material will take a long time to\nbreak down.<\/p>\n\n\n\n Pile size<\/strong><\/p>\n\n\n\n Big is beautiful in the case\nof compost piles, because the larger the pile the smaller the surface area in\nrelation to its volume and the better it\u2019s able to retain heat (a critical\nfactor in rapid decomposition). <\/p>\n\n\n\n The main limit on how large\na pile can be is in its height. If a pile is higher than 6 feet the weight of\nthe pile compresses the interior and it becomes difficult for air to reach the\ncenter (unless specially ventilated). If it can\u2019t get enough air then anaerobic\norganisms may take over. A very tall pile may also be so well insulated that it\ngets too hot in the center (they have actually been known to catch fire). Of\ncourse you aren\u2019t likely to want to make a pile anywhere near 6 feet tall,\nbecause it becomes very difficult to get the heavy materials up that high. In\nreality the size is more limited by your ability to obtain sufficient materials\nand by the physical limitations of constructing it.<\/p>\n\n\n\n Garden\ncompost piles tend to be fairly small because of the limited amount of material\navailable to compost and because most people aren\u2019t physically capable (or\nwilling) to handle very large quantities. The minimum size for a freestanding\npile is about 3 feet by 3 feet by 3 feet. Smaller piles should be enclosed to\nhelp them retain heat and moisture.<\/p>\n\n\n\n Pile shape<\/strong><\/p>\n\n\n\n The only restriction on the\nshape of a pile is that it should have as small a surface areas as possible for\nits volume. This usually means the pile is fairly close to a cube in shape. In\nwet climates the pile should have a peak to help it shed rain (in very wet\nweather you should probably cover it with a tarp to prevent it getting too\nwet). In dry climates it\u2019s better to make the pile flat on top, as this makes\nadding water easier.<\/p>\n\n\n\n pH<\/strong><\/p>\n\n\n\n For most rapid decomposition\nthe accumulated materials in a pile should be close to neutral (pH 6.0 – 7.0),\njust like a healthy soil. If the pH is too high or too low, the right soil\norganisms won\u2019t get to work in sufficient numbers and the pile won\u2019t heat up\nproperly. Bacteria prefer the pH of a pile to be around 6.0 – 7.5, whereas\nfungi are slightly more tolerant of acidity (pH 5.5 – 7.5).<\/p>\n\n\n\n In practice the lower end of\nthe pH range is preferable, as a higher pH increases the production of ammonia\nand hence loss of nitrogen. This is why it isn\u2019t a good idea to add lime to a\npile to alter the pH (add it to the finished compost instead).<\/p>\n\n\n\n Air<\/strong><\/p>\n\n\n\n The compost pile must have a\ngood supply of air for rapid breakdown. Make sure you don\u2019t get it too wet,\nmake it too tall, or compact it by walking, sleeping, or performing fertility\nrites on it. Always be aware of the potential for compaction, especially when\nusing a large proportion of succulent greens or other wet material. You could\neasily end up with rotten silage rather than compost. If this happens you must\nturn and aerate the pile (see below for more on this).<\/p>\n\n\n\n Air must be able to get to\nthe center of the pile for it to work. It\u2019s common practice to put a layer of\nbrush on the ground underneath a pile to improve aeration. You could also use\nold bamboo, or the thick hollow stems of Tithonia, sunflower or other large\nplants. The huge piles of municipal composting operations are commonly aerated\nwith perforated pipe.<\/p>\n\n\n\n Time<\/strong><\/p>\n\n\n\n The time it takes for a pile\nto decay is governed by all of the factors mentioned above and is limited by\nthat factor which is present in the least amount (old Liebigs barrel with a\nshort stave again). If all of these are taken care of optimally your compost\ncould be ready in 3 months or less. If they aren\u2019t then it might take a year or\nmore. Quick compost (see below) can be ready for use in as little as 2 or 3\nweeks, simply because it gives the microorganisms ideal conditions for their\ngrowth.<\/p>\n\n\n\n If you aren\u2019t in a hurry you\ncould ignore most of the advice I\u2019ve given here and just throw stuff into\npiles. Almost anything will decompose if given sufficient time (and kept\nmoist). It won\u2019t be a compost pile though.<\/p>\n\n\n\n Making a compost pile<\/strong><\/p>\n\n\n\n Composting\ntools<\/strong>: The most important compostingtools\nare the fork (ideally a manure fork) and a wheelbarrow for moving all the\nmaterials around. It\u2019s also helpful to have secateurs, a spade, a machete and\nperhaps a large wooden block to facilitate smashing woody materials.<\/p>\n\n\n\n Composting containers<\/strong>: These aren\u2019t necessarywhen making compost on a large\nscale, but they can be useful in some cases.<\/p>\n\n\n\n Home garden piles are\ngenerally too small for optimal heating, because they simply don\u2019t have\nsufficient mass. Compost bins can help by insulating the pile so that it can\nheat up more evenly for good decomposition. Fast piles are usually made in bins\nfor this reason.<\/p>\n\n\n\n Small open piles may also\nlose or gain moisture quickly when exposed to heavy rain or hot sun. Enclosing\nthem in a covered bin reduces this tendency. This is especially important in\nwinter, when a cover may also be necessary. Rain not only leaches out\nnutrients, but also drains away heat.<\/p>\n\n\n\n In small city gardens compost\npiles can attract the attention of one of the most difficult of all garden\npests, complaining neighbors. A neat compost bin can help to minimize\ncomplaints by hiding the pile completely. Remember compost piles are illegal in\nsome places.<\/p>\n\n\n\n Bins may be made from new or\nsalvaged materials, bricks, old pallets, wire, salvaged wood, concrete blocks\nor corrugated iron. Some of the most useful bins have separate compartments,\nwith removable partitions, so the compost is easily turned from one to another.\nThree compartment systems are the best because the pile can be started in the\nfirst bin, transferred to the second one and eventually to the third. By the\ntime it\u2019s finished in the third bin the compost is ready to use.<\/p>\n\n\n\n The cheapest and fastest bin\nis a length of wire fencing made into a large (at least 3 – 4 foot) diameter\ncylinder. This can be lined with cardboard to hold in moisture and heat, or\nblack plastic to absorb the suns heat. <\/p>\n\n\n\n In cold weather you can make\na bin out of spoiled hay bales, covered with corrugated cardboard (these\nmaterials are eventually composted too). Winter piles are sometimes made in\npits to keep them warm, but in rainy climates there can be a problem with\nwaterlogging.<\/p>\n\n\n\n In very hot dry climates\ncompost is sometimes made in pits, as this keeps the compost moister and\ncooler.<\/p>\n\n\n\n When to make compost<\/strong><\/p>\n\n\n\n If you hope to have enough\ncompost for your needs, you will need to make a real effort to keep up with\nmaking piles. It can take 6 months or more for a pile to mature so it\u2019s\nimportant to plan ahead. Some people merely build piles whenever they have a sufficient\naccumulation of materials on hand, others go out actively searching for\nmaterials. It\u2019s a good idea to schedule your compost making activities\n(acquiring materials, building piles, turning piles) in your garden journal,\notherwise they are often among the first things to get neglected when you get\nbusy.<\/p>\n\n\n\n There is no best time to\nbuild a compost pile. You can make one any time the air temperature is high\nenough for the composting process to get started. Often people concentrate on\npile building in spring and fall as materials are most readily available at\nthose times. In spring you have skimmings from the beds, weeds and cover crops,\nwhile in fall you have large quantities of fallen leaves, skimmings from beds\nand crop residues.<\/p>\n\n\n\n The demand for compost is\ngreatest in spring, when you are preparing a lot of beds in a short time. Keep\nthat in mind when planning.<\/p>\n\n\n\n Siting the pile<\/strong><\/p>\n\n\n\n The most important\nrequirement is that the pile be located near to the garden, to reduce the work\nof hauling materials back and forth. If you plan on bringing in manure, leaves\nand other organic materials you might want access for a truck for unloading\nthem easily. In urban areas or small gardens it may be necessary to keep the\npile hidden from the sight of neighbors. In hot climates the pile should be in\nlight shade to reduce water loss from evaporation. In cold climates it should\nbe in a warm sunny place that is sheltered from cold winds.<\/p>\n\n\n\n You might designate a\npermanent composting area, or you might move the piles around the garden, to\nspread out the benefit of the soluble nutrients that leach from the pile. If\nyou put the autumn pile on a bed it will work over the winter and can be\nremoved in spring to leave a warm, clean, fertilized bed ready for planting.\nAnother idea is to put the piles on areas of poor soil you want to improve for\neventual inclusion in the garden.<\/p>\n\n\n\n How to build a pile (using a\nvariation of the Indore method)<\/strong><\/p>\n\n\n\n There is no great mystery to\nmaking compost, basically all you have to do is moisten all of the materials,\ncombine them in the right proportions and sit back and watch. The chart of C: N\nratios given above is a useful guide, but you would need a weighing scale and a\ncomputer to calculate the exact C : N ratios and proportions of materials for\nthe average pile. Fortunately you don\u2019t have to be that precise. A pile with\ntoo much nitrogen will simply vent off the excess nitrogen. A pile with too\nmuch carbon will just take longer to work (urine can be added to supply extra\nnitrogen).<\/p>\n\n\n\n Before you start the pile\nyou may want to fork the ground to better connect the pile to the ground. Begin\nby laying down a 6\u02dd base layer of somewhat woody material (small brush,\nBrassica or sunflower stems). This defines the bottom of the pile and improves\ndrainage and aeration. In dry climates you can forget about this base as you\nwant to conserve moisture. Cover this with a 4\u02dd deep layer of weeds, green\nmanure and bed skimmings, followed by a 2 – 3\u02dd layer of manure (horse or cow is\ngood). Follow this with a sprinkling of rock powders (not liming agents), then\na 3\u02dd layer of wetted straw or dry plants and finally a thin 1\u02dd layer of soil.\nIf any of these layers are dry you should moisten them thoroughly as you lay\nthem down. You could even soak them beforehand to get them thoroughly wet (you\ncan\u2019t make them too wet, as excess water will soon drain off).<\/p>\n\n\n\n Repeat these four layers\n(greens, manure, straw, soil) alternately until the pile is of the desired\nheight (4 – 5 feet is good). Concentrate on building the sides of the pile,\nkeeping them as nearly vertical as possible and the inside will take care of\nitself. If the sides start to slope inwards then pull them back out to near\nvertical with a fork. When you get near the top start to slope the sides\ninwards to give a slight pitched roof effect (a steeper pitch is good in wet\nclimates). Some gardeners finish off the pile with a thick layer of straw,\nwhile others prefer to cap it with a layer of soil.<\/p>\n\n\n\n Piles don\u2019t have to be built\nexactly in this way, there is a lot of room for improvisation. No material is\nindispensable, you can use whatever is available, so long as you keep it in\nroughly the right proportions of carbon to nitrogen.<\/p>\n\n\n\n Examples of various piles<\/strong><\/p>\n\n\n\n 80% manure, 20% straw<\/p>\n\n\n\n 50% green, 50% straw<\/p>\n\n\n\n 20% manure, 40% green, 40%\nstraw<\/p>\n\n\n\n 33% green, 33% straw, 33%\nsoil<\/p>\n\n\n\n Heating<\/strong><\/p>\n\n\n\n You can tell when a pile is\nheating up just by looking at it, because it shrinks rapidly (often overnight)\nas the material consolidates (in cool weather it may also give off steam). If is\nhasn\u2019t shrunk visibly you can check whether it is heating up by putting your\nhand into it. At a depth of 6\u02dd it should be warm, at 12\u02dd it should be almost\ntoo hot to comfortably hold your hand there. <\/p>\n\n\n\n In cool weather a pile may\nbe slow to heat up, or may not heat at all. There\u2019s nothing necessarily wrong,\nit just takes longer for the bacteria to reach a critical mass when it\u2019s cold.\nIf you could get it going somehow it would eventually generate enough heat to\nsustain itself. Old carpet, bins, straw bales, or black plastic can help to\ninsulate and keep it warmer (you might even build it in a hoop house or greenhouse), but it\u2019s best to get the pile\ngoing before it gets so cold that these measures are needed. In many areas\nwinter is too cold for good decomposition (piles need to be enormous to hold\nenough heat at this time).<\/p>\n\n\n\n A compost thermometer is\nhelpful for accurately recording the progress of your piles and gives you a way\nto compare the effectiveness of different mixes of material.<\/p>\n\n\n\n Monitoring moisture content<\/strong><\/p>\n\n\n\n Don\u2019t just build the pile\nand forget about it. It is a living thing and needs to be cared for as if it\nwere another growing bed. Check its moisture content regularly and adjust as\nnecessary.<\/p>\n\n\n\n Dry<\/strong>: A pile\ncan lose a lot of moisture from surfaceevaporation in hot dry weather.\nIf you suspect this is a happening then cover with old cornstalks, a mulch of\nstraw, or a plastic sheet (this can reduce air circulation though). Remove this\ncover when it rains. Regular light watering will replace the small quantity of\nwater lost through evaporation, though you have to be careful not to get the\npile too wet. Don\u2019t let the pile dry out too much, or it will be necessary to\nbreak it apart to re-wet it properly. It\u2019s hard to get the pile evenly moist\nsimply by watering from above, some areas get wet, while others stay dry.<\/p>\n\n\n\n In very hot and dry areas,\ncompost piles are sometimes made in pits, as this helps to keep them moist.<\/p>\n\n\n\n Wet<\/strong>: In cool\nhumid conditions the pile might have tobe covered during heavy rain to\nprevent waterlogging. If the pile gets too wet it may mat down into a gluey\nanaerobic mess. If this happens it will have to be turned to dry it out and get\nair into it. It takes a lot of effort to turn the heavy wet mush, but it\u2019s the\nonly way to dry it out effectively.<\/p>\n\n\n\n Turning the pile<\/strong><\/p>\n\n\n\n It isn\u2019t really necessary to\nturn a well-made and maintained pile, but it speeds up the composting process\nand ensures that the whole pile heats up uniformly. If you don\u2019t turn a pile,\nthe outer 10\u02dd layer of the pile won\u2019t heat up sufficiently to decompose\nproperly, or kill pathogens and weed seeds. When an unturned pile is complete\nthis outer part can be stripped off separately and composted again.<\/p>\n\n\n\n A newly\nturned pile will heat up a second time as more air is supplied and the goodies\nin the outer layers are consumed. It won\u2019t get as hot as it did the first time\nthough. Some gardeners turn their piles a third time to speed up decomposition\n(and sometimes again \u2013 see Quick\nComposting).<\/strong><\/strong><\/p>\n\n\n\n If you want to add ground\nlime to the pile, do it the last time you turn it, after it has cooled down.\nDon\u2019t add it when first building a pile, because it can cause nitrogen to be\nlost as ammonia gas.<\/p>\n\n\n\n Pests<\/strong><\/p>\n\n\n\n If your pile heats up promptly you should have few problems with foraging\npests. Meat, bones and other animal products are the cause of most problems, so\nthey are often kept out of the pile, though any recognizable food waste is a\npotential lure. A cap of soil or straw will keep flies out of a pile until it\nstarts to heat up (then it will soon get too hot for them).<\/p>\n\n\n\n Skunks,\nrats, raccoons, dogs and other animals (I\u2019ve had a bear) can become a problem\nin poorly made compost piles, or those made in stages (as there is always\nedible food in them).<\/p>\n\n\n\n When is it ready?<\/strong><\/p>\n\n\n\n It takes about 6 months to\nproduce fully mature compost. The end result has a rich brown color, no easily\nidentifiable parts (85% of it will go through a half inch screen) and a sweet\nearthy smell (the smell tells you when it\u2019s ready). The presence of earthworms\nindicates it has cooled down sufficiently to be ready for use.<\/p>\n\n\n\n If you really need the\ncompost urgently you can use it after it cools down the first time. It will\nbreak down fully in the soil. Immature compost is sometimes added to clay soil\nto improve its structure, or put in the lower spit when double digging.<\/p>\n\n\n\n To get really fine compost\nfor sowing mixes turn the pile twice and then leave it for a year to decompose\nfully.<\/p>\n\n\n\n Mature compost contains about\n20% organic matter, 5% humus, 1% nitrogen, .7% phosphorus, .5% potassium and a\nlot of trace elements, beneficial fungi, bacteria and other organisms. <\/p>\n\n\n\n Using compost<\/strong><\/p>\n\n\n\n This is pretty much covered\nin other parts of the book. There is really no best time to apply compost. It\nis most often applied in spring, because that\u2019s when most bed preparation goes\non, though it\u2019s also applied throughout the summer when preparing the beds for\nplanting.<\/p>\n\n\n\n Don\u2019t leave mature compost\nstanding around for very long, get it into the soil where it can do some good.\nIf you must keep it for any reason (such as for spring seed starting) keep it\ncovered to prevent leaching, drying out or oxidation.<\/p>\n\n\n\n As you use your compost,\nseparate out any large undecomposed bits and add them to your next pile (or use\nfor mulch). <\/p>\n\n\n\n Troubleshooting<\/strong><\/p>\n\n\n\n Composting is a fairly\npredictable process and if something goes wrong it\u2019s usually fairly easy to\ndiagnose. These are the commonest problems:<\/p>\n\n\n\n Pile doesn\u2019t heat up<\/strong><\/p>\n\n\n\n Too dry<\/strong>: Turn and\nmoisten.<\/p>\n\n\n\n Too cold<\/strong>: Wait\nuntil the weather warms up, insulate, <\/strong>or build a\nbigger pile<\/p>\n\n\n\n Insufficient nitrogen<\/strong>: Add more nitrogen (urine is <\/strong>good – if\nyou can get any).<\/p>\n\n\n\n Too small<\/strong>: There is\ninsufficient volume to the pile, <\/strong>make it\nbigger<\/p>\n\n\n\n Pile smells<\/strong>:<\/p>\n\n\n\n Too much nitrogen<\/strong>:\nThe pile is giving off nitrogen in the form of ammonia. You could turn the pile\nand add more carbon material, or you could do nothing.<\/p>\n\n\n\n Too wet<\/strong>: Turn and\naerate<\/p>\n\n\n\n Compost\nmaterials<\/strong><\/strong><\/p>\n\n\n\n Almost anything that has\nlived can be added to the compost pile, so long as you keep it within the\nappropriate proportions of carbon to nitrogen (see above). You will need a bulk\nsource of high carbon materials and a source of nitrogen. Usually the biggest\nfactors in what goes into the pile is availability, which simply means what can\nyou get in sufficient quantity. Small gardens don\u2019t produce enough material to\nmake an adequate supply of compost, so good organic gardeners also tend to be\ngood scroungers.<\/p>\n\n\n\n Manure<\/strong>: This is\nalmost synonymous with compost for many people, yet others believe manure is\ndetrimental and never use it. Manure provides the nitrogen component of the\npile and is full of microorganisms. Composting manure makes it safer to use in\nthe garden, as the heating destroys pests, pathogens and weed seeds. Some\npeople even compost human manure in hot compost piles. Apparently 3 days\nbetween 130 and 170\u00b0F are sufficient to\nkill all pathogens and render it safe for garden use.<\/p>\n\n\n\n Urine<\/strong>: Sometimes\nknown as H.L.A. (household liquid activator) or liquid gold to disguise its\ntrue origins, urine can be the main source of nitrogen for the compost pile. If\nyou aren\u2019t overly fastidious and are prepared to collect it, urine is actually\na very convenient material and one that has to be disposed of one way or\nanother. Dilute it (4 parts water to 1 part urine) before putting it on the\npile. It is especially useful for getting a reluctant pile to heat up.<\/p>\n\n\n\n Soil<\/strong>: This\nprovides the right decay causing micro-organisms and may help prevent the loss\nof nitrogen. However it isn\u2019t needed in large amounts (that clinging to the\nroots of old plants is generally sufficient) and too much soil may slow the\npile down. In fact soil is sometimes added to the compost pile to prevent it\nfrom heating up too much.<\/p>\n\n\n\n Green vegetation<\/strong>:\nThis is one of the main <\/strong>sources of nitrogen for the\ncompost pile. The commonest materials are those you take straight from the\ngarden, cover crops, weeds and finished crops, but you can also go looking for\nany abundant fast growing (non-pernicious) vegetation, such as Vinca, Japanese\nknotweed, kudzu, ivy, aquatic weeds, algae and cat-tails. Never add the roots\nof pernicious perennial weeds such as bindweed, Bermuda grass or couchgrass to\nthe pile, or any weeds that have set seed. They may come back to haunt you. See\nbelow for more on what not to use in the pile.<\/p>\n\n\n\n You can also plant fast\ngrowing plants specifically for composting (see Soil improving Crops<\/strong> for more\non growing compost crops).<\/p>\n\n\n\n Grass clippings<\/strong>:\nGrass clippings are a rich source <\/strong>of nitrogen\nand other nutrients. They are usually mixed with coarser materials, as they\ntend to mat down and go anaerobic if used alone. Occasionally grass clippings\ncontain viable seeds, and if this is a problem then compost them in a hot pile.<\/p>\n\n\n\n The best place to get grass\nclippings is from neighbors or professional gardeners (they will often unload\ntheir clippings on your property). You may also be able to pick them up from\napartment complexes and sports fields. When gathering from such places you\nshould be aware of the potential accumulation of toxins from nearby roads.\nPesticides aren\u2019t as much of a problem as these are mostly broken down in the\ncomposting process. Don\u2019t take grass clippings from your own lawn though, they should\nremain there to feed the living grass (let\u2019s not get into a discussion about\nwhether you should even have a lawn).<\/p>\n\n\n\n Seaweeds<\/strong>: These add\nvaluable trace minerals to the pile and stimulate microbial activity, but don\u2019t\nadd much humus. Fresh seaweed should be washed thoroughly to eliminate excess\nsalt. Powdered seaweed is best added directly to the soil, as there is no\nadvantage in composting it.<\/p>\n\n\n\n Straw, hay and dried plants<\/strong>: These are high in carbon, the other important ingredient of the\ncompost pile. Spoiled hay is sometimes available for the hauling, though it\u2019s\nvery heavy when wet. It commonly contains weed seeds, so must be composted at a\nsufficiently high temperature to kill them. Straw stems are hollow and so help\nto improve aeration. It doesn\u2019t usually contain weed seeds.<\/p>\n\n\n\n Tree leaves are an excellent\ncompost material and are often available in large quantities. They should be\nchopped or mixed with other materials, as otherwise they tend to mat down.<\/p>\n\n\n\n These materials should be\nwet when added to the pile, as they don\u2019t break down easily when dry (straw was\nonce widely used for thatched roofs).<\/p>\n\n\n\n Sawdust<\/strong>: This is\nultimately a good source of humus, but the decay process is slow because it\ncontains so much carbon. It should only be used in small quantities in the\ncompost pile and should be mixed with a rich source of nitrogen. If you have a\nlarge quantity of sawdust it can be composted in its own special pile (see Wood Waste Composting<\/strong> <\/strong>above).<\/p>\n\n\n\n Kitchen scraps<\/strong>:\nVegetable kitchen scraps are <\/strong>high in nitrogen and other\nnutrients, so are an excellent addition to the pile. Meat, bone and other\nanimal scraps can be used if <\/p>\n\n\n\n you are careful, but are\nbest handled by quick composting, to minimize the time they are attractive to\nscavengers.<\/p>\n\n\n\n The biggest problem with\nkitchen waste is that it\u2019s produced in small quantities steadily, whereas for\ncomposting you need large quantities at one time. You can\u2019t simply add kitchen\nscraps to the pile as they are produced, as your pile will simply become a\nfeeding station for flies, rats, skunks, raccoons, dogs or even bears, which\nisn\u2019t good for you or the animals.<\/p>\n\n\n\n Because\nit isn\u2019t very satisfactory to compost this kind of material incrementally, you\nmay have to find a way to store the stuff until you have accumulated enough for\na pile, without creating a stink or attracting pests. One solution is to empty\nyour kitchen scraps into 5 gallon buckets, cover with a thin layer of shredded\nleaves or sawdust (to stop it smelling) and seal it with an airtight lid. As\neach bucket fills up store it in a cool place until you have enough to build a\npile. This same system is sometimes used with human manure.<\/p>\n\n\n\n Some gardeners pick up large\nquantities of kitchen scraps from restaurants and grocery stores. This works\nwell if you have the capacity and motivation to deal with that much stuff, but\nit can easily turn into a big mess. I once visited a house where the owner\ncomposted fish waste he picked up from the Santa Cruz wharf. His kiwi vines\nwere awesome, but the flies around his composting operation were horrendous and\nfor ever after we spoke of him as \u201cthe lord of the flies\u201d.<\/p>\n\n\n\n Garbage<\/strong>: All\norganic based garbage; newspapers, <\/strong>cardboard,\nclothing (natural fabrics) and more, can be composted if there is no way to\nreuse or recycle them (which is a better way to go)<\/p>\n\n\n\n Highly carbonaceous material\nlike paper and cardboard should ideally be torn into shreds and mixed with\nsucculent greens (don\u2019t merely throw folded up newspapers on the pile).<\/p>\n\n\n\n Semi-woody materials<\/strong>: You can compost small amounts of semi-woody materials such as\nBrassica stems, summer fruit tree prunings, semi-ripe wood and vines. They take\na while to break down, but add a high proportion of valuable humus to the pile.\nYou can hasten decomposition by chopping or shredding. Hand chopping is most\neasily done when turning the pile, as they will already be partially broken\ndown.<\/p>\n\n\n\n Rock\npowders<\/strong>: Some gardeners add rock powders such\nas greensand and rock phosphate to the pile. The organic acids produced during\ndecomposition may help to make their nutrients more available.<\/p>\n\n\n\n Ground limestone<\/strong> <\/strong>(calcium carbonate): This is sometimes used to raise the pH of compost,\nbut it shouldn\u2019t be added when building the pile, as this will increase the\nloss of nitrogen. It should be added when turning the pile for the last time,\nor just before application. <\/p>\n\n\n\n Gypsum<\/strong> <\/strong>(calcium\nsulfate): This is sometimes added to the <\/strong>pile to supply sulfur. It also contains calcium so should only be\nadded after the pile has cooled down.<\/p>\n\n\n\n Non-compostable materials<\/strong><\/p>\n\n\n\n Materials which should not\nbe composted include:<\/p>\n\n\n\n Animal products<\/strong>:\nMany garden books caution <\/strong>against adding meat, fat,\nbones and other animal parts to the pile, as they can attract unwanted insects\nand animals. I have mostly lived in vegetarian households, so I haven\u2019t had\nmuch experience with this. However it would seem to me that if your pile heats\nup quickly and thoroughly, they shouldn\u2019t be much of a problem. I have\ncomposted a number of whole animals with no problems. <\/p>\n\n\n\n Dog and cat manure<\/strong>: This is high in nitrogen and other nutrients, <\/strong>but may also contain some rather unpleasant parasites. It could be\ncomposted in the middle of a hot pile, but why bother? It\u2019s easier to just bury\nit near non-food plants.<\/p>\n\n\n\n Pernicious perennial weed\nroots, <\/strong>weeds with seeds<\/strong>: If\nthese survive the composting process they may cause trouble, as they would go\nstraight back into the garden in a pile of rich compost. You can sometimes tell\nwhere poorly heated, weed seed filled, compost had been applied, by the huge\nnumber of vigorous weeds.<\/p>\n\n\n\n It is possible to compost\nthese materials, but you have to be careful to put them in the center of the\npile, where it gets hot enough to kill them. If you aren\u2019t sure about this, it\nis better to keep them out of the pile. It isn\u2019t worth the risk for the amount\nof material involved. I try to be conscientious about not mixing such materials\nwith good compostable stuff (and try to cut weeds before they set seed).<\/p>\n\n\n\n You can kill perennial weeds\nby drying them out in the sun before composting, but make absolutely sure they\nare dead. Perhaps leave them in a heap of their own for a while, before\ncomposting them. <\/p>\n\n\n\n A good way to compost\npernicious weeds is anaerobically, in a plastic bag.<\/p>\n\n\n\n Woody and thorny branches<\/strong>: These materials won\u2019t break down in a normal compost pile, they\nneed special treatment (see Brush Composting<\/strong>. Keep thorny plants out of the pile because the thorns can easily\nend up in your anatomy.<\/p>\n\n\n\n Glossy and colored paper<\/strong>: Though these are now commonly made from non- toxic inks, some\nmay still contain heavy metals and you can\u2019t be sure which are safe. I avoid\nthem.<\/p>\n\n\n\n Pressure treated wood<\/strong>: This is very toxic and doesn\u2019t break very easily. No one in\ntheir right mind would try and compost this, in fact I don\u2019t even know why I\u2019m\nmentioning it. I also avoid plywood sawdust. <\/p>\n","protected":false},"excerpt":{"rendered":"![\"\"](\"https:\/\/greenmanpublishing.com\/wp-content\/uploads\/2019\/09\/compost-pile-1-1024x768.jpg\")
\n Carbon to nitrogen ratio of common materials<\/strong>\n This is approximate, as\n natural materials can vary a lot (carbon is first, nitrogen second).\n \n <\/td><\/tr> \n Activated sludge\n \n <\/td> \n 6 : 1\n \n <\/td><\/tr> \n Alfalfa hay\n \n <\/td> \n 12 – 20 : 1\n \n <\/td><\/tr> \n Apple pomace\n \n <\/td> \n 12 : 1\n \n <\/td><\/tr> \n Blood meal\n \n <\/td> \n 3 : 1\n \n <\/td><\/tr> \n Bonemeal\n \n <\/td> \n 4 : 1\n \n <\/td><\/tr> \n Bracken Fern\n \n <\/td> \n 48 : 1\n \n <\/td><\/tr> \n Cardboard\n \n <\/td> \n 150 : 1\n \n <\/td><\/tr> \n Coffee grounds\n \n <\/td> \n 20 : 1\n \n <\/td><\/tr> \n Comfrey\n \n <\/td> \n 10 : 1\n \n <\/td><\/tr> \n Corn stalks\n \n <\/td> \n 60 : 1\n \n <\/td><\/tr> \n Cottonseed meal\n \n <\/td> \n 5 – 20 : 1\n \n <\/td><\/tr> \n Dry leaves\n \n <\/td> \n 50 : 1\n \n <\/td><\/tr> \n Grass hay\n \n <\/td> \n 80 : 1\n \n <\/td><\/tr> \n Green plants\n \n <\/td> \n 15 – 25 : 1\n \n <\/td><\/tr> \n Hay\n \n <\/td> \n 25 ; 1\n \n <\/td><\/tr> \n Humus\n \n <\/td> \n 12 : 1\n \n <\/td><\/tr> \n Kitchen garbage\n \n <\/td> \n 15 – 25 : 1\n \n <\/td><\/tr> \n Leaf litter\n \n <\/td> \n 60 – 100 : 1\n \n <\/td><\/tr> \n Leaves, Alder\n \n <\/td> \n 25 : 1\n \n <\/td><\/tr> \n Oak\n \n <\/td> \n 50 : 1\n \n <\/td><\/tr> \n Pine\n \n <\/td> \n 60 – 100 : 1\n \n <\/td><\/tr> \n Legume hay\n \n <\/td> \n 12 – 25 : 1\n \n <\/td><\/tr> \n Manure, Chicken\n \n <\/td> \n 7 : 1\n \n <\/td><\/tr> \n Cow\n \n <\/td> \n 18 : 1\n \n <\/td><\/tr> \n Horse\n \n <\/td> \n 25 : 1\n \n <\/td><\/tr> \n Human\n \n <\/td> \n 10 : 1\n \n <\/td><\/tr> \n Oat straw\n \n <\/td> \n 50 : 1\n \n <\/td><\/tr> \n Paper\n \n <\/td> \n 150 : 1\n \n <\/td><\/tr> \n Seaweed\n \n <\/td> \n 19 : 1\n \n <\/td><\/tr> \n Slaughterhouse waste\n \n <\/td> \n 2 : 1\n \n <\/td><\/tr> \n Sawdust\n \n <\/td> \n 150 – 500 : 1\n \n <\/td><\/tr> \n Sewage\n \n <\/td> \n 20 : 1\n \n <\/td><\/tr> \n Soil organisms\n \n <\/td> \n 7 : 1\n \n <\/td><\/tr> \n Straw\n \n <\/td> \n 75 – 150 : 1\n \n <\/td><\/tr> \n Topsoil\n \n <\/td> \n 11 : 1\n \n <\/td><\/tr> \n Urine\n \n <\/td> \n 0.3 : 1\n \n <\/td><\/tr> \n Vegetable waste\n \n <\/td> \n 12 – 25 : 1\n \n <\/td><\/tr> \n Weeds\n \n <\/td> \n 30 : 1\n \n <\/td><\/tr> \n Wood chips\n \n <\/td> \n 400 : 1\n \n <\/td><\/tr><\/tbody><\/table>\n\n\n\n \n Temperatures to kill\n pathogens<\/strong>\n Lower temperatures will\n kill pathogens too, but require longer heating times. \n \n 30 minutes at:\n 176\u00b0F (80\u00b0 C): Will kill\n weed seeds\n 158\u00b0F (70\u00b0 C): Will kill\n insects, bacteria, viruses.\n 140\u00b0F (60\u00b0 C): Will kill\n slugs, fusarium, botrytis.\n 122\u00b0F (50\u00b0 C): Will kill\n fungi, nematodes\n \n <\/td><\/tr><\/tbody><\/table>\n\n\n\n