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Composting 101
“Inside a compost pile, billions of decay organisms feed, grow, reproduce, and die, recycling household and garden wastes into an excellent organic fertilizer and soil conditioner.” Rodale’s Encyclopedia of Organic Gardening
The decomposition process occurs gradually in nature, but building a compost pile intervenes to speed things up. Compost can provide a complete range of major, minor, and micro nutrients. By nature it contains an intense volume of microorganisms, as well as the many enzymes, amino acids, and hormones associated with their metabolic activities. By making compost, gardeners create a source of high-quality nutrition for their garden and eliminate the need to buy commercial fertilizers. Compost improves soil structure, and moisture retention, and can protect plants from certain diseases.
Building the Pile
The goal in building a compost pile is to provide the best possible conditions for the proliferation of a hardworking micro-herd. Introduce organisms to the pile with a starter culture of finished compost, rich garden soil, or apply a commercial compost activator. Composting organisms’ needs are simple: a balanced diet, water, air, and warmth.
Anything of living origin can be composted, but the quality and quantity of the materials determines the nutrient value of the finished compost. Compost organisms require the correct proportion of carbon for energy and nitrogen for forming protein – called the C/N ratio – to function efficiently. If the C/N ratio is too high (i.e. excess carbon), decomposition slows down and N is depleted. Too low a C/N ratio (too much N) wastes N by letting it escape into the air, causing unpleasant odors, and into the water. The ideal C/N ratio is 25-30:1. In general, high-carbon materials are brown or yellow, dry, and bulky. High N materials tend to be green, moist, and sloppy. Here is a list of common compost ingredients, and their C/N ratios:
Alfalfa hay 12:1
Table scraps 15:1
Grass Clips 19:1
Rotted manure 20:1
Young weeds 30:1
Fruit wastes 35:1
Leaves 40:1-80:1
Straw 80:1
Pine needles 110:1-60:1
Paper 170:1
Sawdust 500:1
Most organic materials supply a wide range of the other nutrients needed by compost organisms and plants. The greater the variety of materials you include in your compost, the greater your certainty of creating a nutritionally balanced product. Use additions of mineral-rich materials such rock phosphate or greensand to tailor the nutrients in your compost to match the needs of your soil and plants. Composting these materials makes them more available.
Using lime in compost piles is not always a desirable addition to the compost pile. Particularly when composting manure, lime causes the release of N into the air as ammonia, reducing the N available to compost organisms and plants. Replace the calcium supplied by lime with egg shells, bonemeal, or wood ashes (which also contributes K). Like lime, wood ashes are alkaline and will raise the pH of compost. Use wood ash sparingly, as it is highly concentrated.
Moisture
Living organisms need water, but too much moisture drives out air, drowns the pile, and washes away nutrients. Good compost is field capacity, or like a damp sponge. To control moisture levels build your pile with a bottom layer if gravel, brush, sand, etc to make sure it never sits in a puddle. Sprinkle the pile with water as you build it, and add water as necessary when you turn, since allowing the pile to completely dry out interrupts the decay process. Put very wet materials near absorbent materials like leaves or sawdust. Excess moisture will prevent proper heating of the pile. Shape the pile to work with weather conditions. In humid climates a sloped mound repels water, while in dry climates a sunken top collects it.
Aeration
Supplying enough air to all parts of a compost pile will encourage thorough decomposition, and is the key to successful composting. Frequent turning is the most straightforward way, but there are other aeration techniques to use in addition to turning or instead of turning. Build a base of coarse materials like brush or woodchips to allow air penetration from below. Shred leaves, hay, and garden debris before composting. Use paper and grass clippings sparingly, because they tend to form impermeable mats when wet. Poke holes in the pile with a stick or crowbar, or use a dedicated compost crank (a tool used to aerate compost). Bury perforated drainpipe at intervals in a passive compost pile as an excellent way to improve aeration. Sunflower stalks and straw also conduct air into compost. Finally, limit both the height and width of the pile to 5’ to avoid compression.
Too large a pile interferes with aeration, but a minimum size of 3’ in each dimension is needed in order for heating to occur. Given the proper C/N ratio, moisture, and aeration, compost will heat up even in cold weather. A hot pile can reach 160F but will produce satisfactory results at 120F. Northern composters sometimes cover their pile with hay bales or leaves to help composting continue throughout the winter.
Making Hot Compost
Compost piles range from quick, hot composting requiring effort and attention to slow, cool techniques that take less trouble. Quick compost is generally ready to use in less than eight weeks and can be finished in as little as two weeks. Frequent turning is the secret, if you can call it that. Turning keeps the compost well aerated so that decomposers can work efficiently. Keep hot compost working effectively by monitoring the pile and turning when the temperature drops. The object is to maintain temperature between 113-158F until decomposition is complete. A thermometer is helpful but not essential; you can stick a hand into the pile to see how hot it is. Or insert a metal rod into the pile, if the rod feels hot to the touch after a few minutes the pile is heating properly.
The main advantage of hot composting is the speed – even in cooler climates you can process six or more batches in a season. It’s the most effective way to build fertility when you start a new location. The other major benefit is the heat. Hot composting temperatures, maintained over several weeks, kill most weed seeds and pathogens.
The major disadvantage of quick composting is the labor involved in turning the pile every few days. It is also less forgiving, requiring adjustment when moisture levels and C/N ratios are wrong. The pile must also be built all at once, so compostables must be saved until the start of a new pile. Hot composting also conserves less N than cooler methods because fast bacterial growth requires extra N, some of which inevitably drifts off as ammonia. Finally, the high temperatures can kill off beneficial bacteria and fungi that attack pathogens. To combat these problems I add slightly more N than I plan to use in the finished product, and allow several weeks of cooler temperatures after adequate heating to allow beneficials to repopulate.
Getting Started
Starting from scratch, I gather together leaves and grass clippings. One easy start involves running a mower over a leaf covered lawn. The collection bag will contain chopped leaves and clippings, providing a near perfect C/N ratio. Clippings mixed in this way will not “mat” as pure clippings will. Adding food scraps collected a few weeks in advance will provide nice diversity to the green matter in the pile. Manure from a local field can also be added (horse manure is best since it contains a near perfect C/N ratio, and balanced N-P-K), but use rotted manure instead of fresh (rotted will not smell). Gather the material into a pile 3’ wide and 3’ tall. Late summer lawn trimmings, containing leaves, is one readily available source for this high volume of material. Supplement the pile with sawdust if it seems too “wet”: i.e. too high a N ratio. To this mix I add kelp meal, alfalfa meal, greensand, rock phosphate, wood ash, and high P Guano. Finally, I add a gallon of finished compost, or 2 cups of commercial innoculant. Mix and wet the pile thoroughly. The pile is now complete. Leaving the pile as is will yield finished compost in about 6 months, even with no further attention.
What if I need the finished product sooner? Here’s a trick to make aerating the mix easier. I take a 4’ x 10’ section of welded wire fencing and encircled it. Fasten the ends of the fencing together with reusable clips. Add the piled compost to this pen, and drive a 2x4 into the center of the pile leaving at least 12” above the pile (this will direct moisture into the pile). I turn it every two or three days, or whenever it cools, by unclipping the pen and setting it up beside the freestanding pile. Turn the pile into the now-empty pen. In dry weather I water the pile lightly but thoroughly as I turn. This method will yield finished compost in about 8 weeks.
For best results, I like to ensure a pile gets at least a month of high heat composting to kill pathogens and weed seeds. Once the pile approaches maturity (around 6 weeks) I will allow it to cool, encouraging beneficial populations to rebound. To guarantee a thriving beneficial population I water the pile with compost tea or commercial inoculants. Within 2 weeks the mix should be cool, mature, and fully populated by beneficial microbes. This process gets around the risks commonly associated with bringing outdoor soil indoors. The pile reached 150F, and was then repopulated by disease fighting microbes and so will be safe for indoor use.
Using Compost Indoors
Finished compost is a versatile material that I apply freely at almost any stage of growth. I screen my compost to remove large pieces (use these pieces to seed the next pile) and mix the fine particles with sand, peat moss, bark, and perlite to create a custom soil mix. I cut the compost about 50/50 with peat, and add roughly equal portions of perlite and a bark/sand mix. Here is a sample recipe:
Per 50 gal soil:
- 10-15 gal compost
- 10-15 gal Promix
- 10-12 gal perlite
- 10-12 gal sand/bark mix
This incredibly rich mixture relies totally on the nutrients provided in the compost. Adding the soil amendments to the composting process allows time for microbial life to act on the insoluble elements creating a balanced mix of both immediately available and long term nutrition. Contrary to popular belief, pasteurization is unnecessary – heating compost actually suppresses disease-fighting microbes, allowing airborne pathogens to populate the growing medium. When plants need some immediate care, perk them up with a nutrient-rich compost tea. Just add about 4c of finished compost to 5 gal of water and bubble 24-48 hours, or add the compost to a tea bag and steep. Dilute the resulting tea to a weak tea color (usually about 4:1 dilution) and water as necessary. Double the dilution and the tea works as a foliar spray as well. Filtering the tea protects delicate spray nozzles.
Compost and Soil Remixing
When building soil for continuous remixes always be sure to include adequate wood fiber. Peat becomes increasingly acidic over time, and the longevity of the mix will depend on cutting this acidity will sturdy inert materials (bark, chopped stems, saw dust, etc). In the mix above both the compost and bark represent substantial contributions of wood fiber. I compost continually, as soon as one pile matures I start another (seeding the fresh pile with screened chunks from the previous pile). During the 2-3 months between transplant and harvest another mature batch of compost will become available, thus perpetuating the cycle. Add less of the meals and minerals to any compost pile meant to reinvigorate a soil remix, since the soil already contains a base of these slow to break down elements.
If you have the space indoors, keeping a 50 gal container full of reclaimed potting soil can serve as an indoor compost bin. Add garden waste directly to the bin (used tea material, chopped leaf and stem, etc), and turn the bin regularly. After resting for 4-6 weeks this reclaimed soil will be ready for new plants. Add any amendments necessary to replace what the plants consumed, and add extra if any plants showed deficiencies. Keeping an active pile running outside will help by providing a premium source of organic material to add to soil remixes. Typically, I add 5-10 gal of mature compost to reclaimed soil, and enough bark/perlite to keep the mix airy, before planting. Using homemade compost instead of commercial products (like mushroom compost, composted manure, and wormcast) will noticeably enhance the quality of your produce.
Conclusion
Compost and compost teas can replace the use of commercial fertilizers in your garden. Proper composting requires some experience, but will result in a balanced and complete fertilizer of unmatched quality. Remember, the quality of the compost depends on the quality of what goes into it. Food waste is an important addition to the diversity of the pile, so eat well and so will your plants. Seasonal fruits and vegetables provide a wealth of organic waste to enrich your compost. Redirecting food waste from your garbage can to the compost pile will lower trash output and increase compost quality. Fish bones and crushed crab shells are also excellent compost materials, and are the basis of crab and fish meals. Look around in your community for available resources to help enrich your compost. Get manure from a horse farm, yard waste from neighbors, fish and crab waste from a fish market, food waste from a restaurant, granite dust from a mason, etc. If someone cuts down a tree stop off and gather a bag of saw dust, but above all save every scrap of food waste you can. Get resourceful and plan ahead to ensure you always have prime compostables on hand to start a new pile. Putting together a personalized mix tailored to your environment and individual needs will out-perform any product on the market.
3_Blind_Mice
“Inside a compost pile, billions of decay organisms feed, grow, reproduce, and die, recycling household and garden wastes into an excellent organic fertilizer and soil conditioner.” Rodale’s Encyclopedia of Organic Gardening
The decomposition process occurs gradually in nature, but building a compost pile intervenes to speed things up. Compost can provide a complete range of major, minor, and micro nutrients. By nature it contains an intense volume of microorganisms, as well as the many enzymes, amino acids, and hormones associated with their metabolic activities. By making compost, gardeners create a source of high-quality nutrition for their garden and eliminate the need to buy commercial fertilizers. Compost improves soil structure, and moisture retention, and can protect plants from certain diseases.
Building the Pile
The goal in building a compost pile is to provide the best possible conditions for the proliferation of a hardworking micro-herd. Introduce organisms to the pile with a starter culture of finished compost, rich garden soil, or apply a commercial compost activator. Composting organisms’ needs are simple: a balanced diet, water, air, and warmth.
Anything of living origin can be composted, but the quality and quantity of the materials determines the nutrient value of the finished compost. Compost organisms require the correct proportion of carbon for energy and nitrogen for forming protein – called the C/N ratio – to function efficiently. If the C/N ratio is too high (i.e. excess carbon), decomposition slows down and N is depleted. Too low a C/N ratio (too much N) wastes N by letting it escape into the air, causing unpleasant odors, and into the water. The ideal C/N ratio is 25-30:1. In general, high-carbon materials are brown or yellow, dry, and bulky. High N materials tend to be green, moist, and sloppy. Here is a list of common compost ingredients, and their C/N ratios:
Alfalfa hay 12:1
Table scraps 15:1
Grass Clips 19:1
Rotted manure 20:1
Young weeds 30:1
Fruit wastes 35:1
Leaves 40:1-80:1
Straw 80:1
Pine needles 110:1-60:1
Paper 170:1
Sawdust 500:1
Most organic materials supply a wide range of the other nutrients needed by compost organisms and plants. The greater the variety of materials you include in your compost, the greater your certainty of creating a nutritionally balanced product. Use additions of mineral-rich materials such rock phosphate or greensand to tailor the nutrients in your compost to match the needs of your soil and plants. Composting these materials makes them more available.
Using lime in compost piles is not always a desirable addition to the compost pile. Particularly when composting manure, lime causes the release of N into the air as ammonia, reducing the N available to compost organisms and plants. Replace the calcium supplied by lime with egg shells, bonemeal, or wood ashes (which also contributes K). Like lime, wood ashes are alkaline and will raise the pH of compost. Use wood ash sparingly, as it is highly concentrated.
Moisture
Living organisms need water, but too much moisture drives out air, drowns the pile, and washes away nutrients. Good compost is field capacity, or like a damp sponge. To control moisture levels build your pile with a bottom layer if gravel, brush, sand, etc to make sure it never sits in a puddle. Sprinkle the pile with water as you build it, and add water as necessary when you turn, since allowing the pile to completely dry out interrupts the decay process. Put very wet materials near absorbent materials like leaves or sawdust. Excess moisture will prevent proper heating of the pile. Shape the pile to work with weather conditions. In humid climates a sloped mound repels water, while in dry climates a sunken top collects it.
Aeration
Supplying enough air to all parts of a compost pile will encourage thorough decomposition, and is the key to successful composting. Frequent turning is the most straightforward way, but there are other aeration techniques to use in addition to turning or instead of turning. Build a base of coarse materials like brush or woodchips to allow air penetration from below. Shred leaves, hay, and garden debris before composting. Use paper and grass clippings sparingly, because they tend to form impermeable mats when wet. Poke holes in the pile with a stick or crowbar, or use a dedicated compost crank (a tool used to aerate compost). Bury perforated drainpipe at intervals in a passive compost pile as an excellent way to improve aeration. Sunflower stalks and straw also conduct air into compost. Finally, limit both the height and width of the pile to 5’ to avoid compression.
Too large a pile interferes with aeration, but a minimum size of 3’ in each dimension is needed in order for heating to occur. Given the proper C/N ratio, moisture, and aeration, compost will heat up even in cold weather. A hot pile can reach 160F but will produce satisfactory results at 120F. Northern composters sometimes cover their pile with hay bales or leaves to help composting continue throughout the winter.
Making Hot Compost
Compost piles range from quick, hot composting requiring effort and attention to slow, cool techniques that take less trouble. Quick compost is generally ready to use in less than eight weeks and can be finished in as little as two weeks. Frequent turning is the secret, if you can call it that. Turning keeps the compost well aerated so that decomposers can work efficiently. Keep hot compost working effectively by monitoring the pile and turning when the temperature drops. The object is to maintain temperature between 113-158F until decomposition is complete. A thermometer is helpful but not essential; you can stick a hand into the pile to see how hot it is. Or insert a metal rod into the pile, if the rod feels hot to the touch after a few minutes the pile is heating properly.
The main advantage of hot composting is the speed – even in cooler climates you can process six or more batches in a season. It’s the most effective way to build fertility when you start a new location. The other major benefit is the heat. Hot composting temperatures, maintained over several weeks, kill most weed seeds and pathogens.
The major disadvantage of quick composting is the labor involved in turning the pile every few days. It is also less forgiving, requiring adjustment when moisture levels and C/N ratios are wrong. The pile must also be built all at once, so compostables must be saved until the start of a new pile. Hot composting also conserves less N than cooler methods because fast bacterial growth requires extra N, some of which inevitably drifts off as ammonia. Finally, the high temperatures can kill off beneficial bacteria and fungi that attack pathogens. To combat these problems I add slightly more N than I plan to use in the finished product, and allow several weeks of cooler temperatures after adequate heating to allow beneficials to repopulate.
Getting Started
Starting from scratch, I gather together leaves and grass clippings. One easy start involves running a mower over a leaf covered lawn. The collection bag will contain chopped leaves and clippings, providing a near perfect C/N ratio. Clippings mixed in this way will not “mat” as pure clippings will. Adding food scraps collected a few weeks in advance will provide nice diversity to the green matter in the pile. Manure from a local field can also be added (horse manure is best since it contains a near perfect C/N ratio, and balanced N-P-K), but use rotted manure instead of fresh (rotted will not smell). Gather the material into a pile 3’ wide and 3’ tall. Late summer lawn trimmings, containing leaves, is one readily available source for this high volume of material. Supplement the pile with sawdust if it seems too “wet”: i.e. too high a N ratio. To this mix I add kelp meal, alfalfa meal, greensand, rock phosphate, wood ash, and high P Guano. Finally, I add a gallon of finished compost, or 2 cups of commercial innoculant. Mix and wet the pile thoroughly. The pile is now complete. Leaving the pile as is will yield finished compost in about 6 months, even with no further attention.
What if I need the finished product sooner? Here’s a trick to make aerating the mix easier. I take a 4’ x 10’ section of welded wire fencing and encircled it. Fasten the ends of the fencing together with reusable clips. Add the piled compost to this pen, and drive a 2x4 into the center of the pile leaving at least 12” above the pile (this will direct moisture into the pile). I turn it every two or three days, or whenever it cools, by unclipping the pen and setting it up beside the freestanding pile. Turn the pile into the now-empty pen. In dry weather I water the pile lightly but thoroughly as I turn. This method will yield finished compost in about 8 weeks.
For best results, I like to ensure a pile gets at least a month of high heat composting to kill pathogens and weed seeds. Once the pile approaches maturity (around 6 weeks) I will allow it to cool, encouraging beneficial populations to rebound. To guarantee a thriving beneficial population I water the pile with compost tea or commercial inoculants. Within 2 weeks the mix should be cool, mature, and fully populated by beneficial microbes. This process gets around the risks commonly associated with bringing outdoor soil indoors. The pile reached 150F, and was then repopulated by disease fighting microbes and so will be safe for indoor use.
Using Compost Indoors
Finished compost is a versatile material that I apply freely at almost any stage of growth. I screen my compost to remove large pieces (use these pieces to seed the next pile) and mix the fine particles with sand, peat moss, bark, and perlite to create a custom soil mix. I cut the compost about 50/50 with peat, and add roughly equal portions of perlite and a bark/sand mix. Here is a sample recipe:
Per 50 gal soil:
- 10-15 gal compost
- 10-15 gal Promix
- 10-12 gal perlite
- 10-12 gal sand/bark mix
This incredibly rich mixture relies totally on the nutrients provided in the compost. Adding the soil amendments to the composting process allows time for microbial life to act on the insoluble elements creating a balanced mix of both immediately available and long term nutrition. Contrary to popular belief, pasteurization is unnecessary – heating compost actually suppresses disease-fighting microbes, allowing airborne pathogens to populate the growing medium. When plants need some immediate care, perk them up with a nutrient-rich compost tea. Just add about 4c of finished compost to 5 gal of water and bubble 24-48 hours, or add the compost to a tea bag and steep. Dilute the resulting tea to a weak tea color (usually about 4:1 dilution) and water as necessary. Double the dilution and the tea works as a foliar spray as well. Filtering the tea protects delicate spray nozzles.
Compost and Soil Remixing
When building soil for continuous remixes always be sure to include adequate wood fiber. Peat becomes increasingly acidic over time, and the longevity of the mix will depend on cutting this acidity will sturdy inert materials (bark, chopped stems, saw dust, etc). In the mix above both the compost and bark represent substantial contributions of wood fiber. I compost continually, as soon as one pile matures I start another (seeding the fresh pile with screened chunks from the previous pile). During the 2-3 months between transplant and harvest another mature batch of compost will become available, thus perpetuating the cycle. Add less of the meals and minerals to any compost pile meant to reinvigorate a soil remix, since the soil already contains a base of these slow to break down elements.
If you have the space indoors, keeping a 50 gal container full of reclaimed potting soil can serve as an indoor compost bin. Add garden waste directly to the bin (used tea material, chopped leaf and stem, etc), and turn the bin regularly. After resting for 4-6 weeks this reclaimed soil will be ready for new plants. Add any amendments necessary to replace what the plants consumed, and add extra if any plants showed deficiencies. Keeping an active pile running outside will help by providing a premium source of organic material to add to soil remixes. Typically, I add 5-10 gal of mature compost to reclaimed soil, and enough bark/perlite to keep the mix airy, before planting. Using homemade compost instead of commercial products (like mushroom compost, composted manure, and wormcast) will noticeably enhance the quality of your produce.
Conclusion
Compost and compost teas can replace the use of commercial fertilizers in your garden. Proper composting requires some experience, but will result in a balanced and complete fertilizer of unmatched quality. Remember, the quality of the compost depends on the quality of what goes into it. Food waste is an important addition to the diversity of the pile, so eat well and so will your plants. Seasonal fruits and vegetables provide a wealth of organic waste to enrich your compost. Redirecting food waste from your garbage can to the compost pile will lower trash output and increase compost quality. Fish bones and crushed crab shells are also excellent compost materials, and are the basis of crab and fish meals. Look around in your community for available resources to help enrich your compost. Get manure from a horse farm, yard waste from neighbors, fish and crab waste from a fish market, food waste from a restaurant, granite dust from a mason, etc. If someone cuts down a tree stop off and gather a bag of saw dust, but above all save every scrap of food waste you can. Get resourceful and plan ahead to ensure you always have prime compostables on hand to start a new pile. Putting together a personalized mix tailored to your environment and individual needs will out-perform any product on the market.
3_Blind_Mice
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