This page is designed to be a troubleshooting guide for the reader interested in starting a new compost system, but uncertain which of the many systems is ideal for the reader’s existing conditions. To this end, this page is structured like a questionnaire that helps determine which system is most suitable. Simply answer the questionnaire by clicking ‘yes’ or ‘no’ or the varying answer below the question, and the page will advance to the appropriate page. After answering several questions, you will arrive to the best compost system, given your conditions. The options are arranged in order of simplicity, meaning if too little information is given, or if the reader isn’t subject to extensive circumstances, a very simple system will be the default.
Alternatively, if you already know which compost system you want to build, you can jump to that section via the table of contents.
I hope you enjoy this page, share it widely and most of all, live a more ecological life for yourself, loved ones, and our planet.
What is it?
Hugelkultur is nature’s equivalent to sweeping problems under the bed. You have the mess of organic matter and if you just throw cover over it, like a rug in the bedroom, and pretend that’s not a problem. The result: a nutrition-packed, moisture-holding cache of growth potential! Plant right on top of it. The slow decomposition of the materials below feeds the plant life above. The structure can be piled on the surface of the earth or a hole can be excavated and organic waste can be thrown into it. If you follow the subterranean approach, first dig a ditch, fill it with the logs and nitrogen-rich organic matter, and cover it with a layer of top soil. The deeper you bury your woody material the better. If you’re able to excavate down, the Hugelkultur will hold more moisture longer. When buried, Hugelkultur beds will retain even more water than raised beds. If you construct your Hugelkultur without first excavated, occasional water is necessary. Also, try layering your organic scraps, rather than putting everything in all at once.
Above Ground or Underground Construction
Location: Sunny or partially shady
Bottom layer: logs and thick twigs (woody materials)
Next layer: a thick pile of dead leaves. You can also use dry straw
Middle layer: lawn clippings, green leaves
Penultimate layer: mature compost
Top layer: topsoil
The rotting wood acts as a carbon source and the grass clippings are a nitrogen source, alerting you to the fact that some decomposition is going to take place. By using carbon-rich fresh wood, you may decrease the overall nitrogen content of the pile in the short term, because the wood will initially rob the surrounding matter of nitrogen. This is counteracted by using rotting logs that have absorbed much or all of their total nitrogen holding capacity, and by adding strong sources of nitrogen, like grass clippings or manure, to the Hugelkultur as it is built. Adding urine to the Hugelkultur bed periodically to feed the nitrogen need of the wood is also highly effective. After fresh wood absorbs nitrogen to its maximum capacity, it will start to break down faster and start giving nitrogen back in the process. If you use wood chips, or many smaller twigs and branches, you have a greater surface area to deal with in regards to nitrogen absorption and should add the appropriate amount of “greens”.
As the wood breaks down further, it will create air pockets that bacteria and mycelium can invade, further hastening the decomposition. These pockets will eventually collapse, shrinking the size of the Hugelkultur over the first year or two. This is normal settling and can be counteracted a bit by adding a fresh layer of chop and drop green manure or compost to the surface of the Hugelkultur bed each year. It can also be accounted for by starting out with a bed slightly larger than you intend it to be once settled.
A pile of wood has a lot of energy in it — imagine burning it in a bonfire. This release of energy is equal to the energy produced during the decomposition, but consolidated into a short period of time, while the decomposition process takes months or years. As the Hugelkultur bed decomposes this energy will generate heat to help stimulate root growth as well as extend your growing season. This energy also takes the form of fuel for all the life in the soil: mushrooms, worms, termites, beetles… everything! If things like termites end up in abundance to the point of being overwhelming, simply run some chickens over your Hugelkultur bed to turn a nuisance into an asset.
To get the most benefits out of a Hugelkultur bed, build it to an initial height of 2.1m! This will shrink to 1.8m or less within the first few months to a year. An often overlooked benefit to having larger raised beds in the form of mounds is an increase in surface area available to plant.
Hugelkultur bed retain lots of water. A buried piece of wood is like a sponge in the ground. After a rain, any nutrients in the top soil are washed deeper into the ground, but in a Hugelkultur bed this water and nutrients are captured by the rotting wood. During dry spells or droughts the moisture contained within the rotting logs persists. A 60cm tall, above ground, Hugelkultur bed can maintain a usable level of moisture for about 3 weeks after it is saturated. Larger beds of 1.8m can hold enough water for an entire growing season. All of this extra moisture retention in areas that receive moderate rainfall can often lead to riparian species growing where you would not otherwise find them. As the bed decomposes, the moisture retaining wood will become humus that cannot hold water quite as well as the rotting wood, but makes up for this by being able to hold onto other useful nutrients and oxygen better than the wood alone.
Hugelkultur is a useful way to dispose of unwanted woody organic matter. By simply pushing brush into a pile, burying it under some grass clippings and some excess poor quality soil, the problem of the getting rid of all their “waste” is solved. The side effect to this activity was to create a fertile bed ripe for planting.
If you are harvesting the woody matter locally, by installing a Hugelkultur bed you can save a lot of energy that would otherwise be used just in disposing of it. Often times municipalities have green waste programs, such as tree clearing around power lines or keeping the sides of the roads mowed, that can offer you a free local source of waste material to build a Hugelkultur bed in an area with no available brush, such as in a suburban neighborhood. Also look toward local businesses such as arborists or landscapers to acquire larger logs. All of these activities can help reduce the load of transporting these materials to a waste site while at the same time fueling a fertile plot of productive land. Since the logs can be used whole in Hugelkultur you don’t even need to spend energy chipping them.
Just make a little volcano-shaped hill of your food scrap and yard clippings. The shape with the dip in the top will funnel water into the center, rather than just pouring down the side. That’s a protip. Here’s another: chop ingredients into small pieces before placing them on the compost pile to speed up decomposition. The front-end work will expedite the breakdown, and you’ll thank yourself later. Spray water into the volcano’s mouth to get the bacteria going. Stop before the surrounding area get soggy. Water depending on the temperature and humidity.
Turnover the pile to ensure proper air circulation which speeds the decomposition process by encouraging beneficial bacteria and fungi growth. More frequent turning will help if you need to speed up the process or if your compost pile has a strong odor. Try to keep food scraps covered with brown, dry ingredients to reduce attracting pest. Avoid adding dirt to your pile.
What to Put on Your Pile
Fruits and vegetable waste, egg shells, coffee grounds, tea bags, paper napkins, lawn clippings used in thin layers, mulched leaves, disease- and pest-free plants as long as they are not weeds, shredded paper, straw, pine needles, marijuana stems,
What to Avoid Putting In
Animal products (they attract pests), bread (doesn’t breakdown very well), paper with film or wax, processed foods, body parts, feces, anything that you would not want to contaminate your garden, waterways, or soil. And dirt. You don’t need to put dirt in a compost pile; that just slows down the process.
How to Collect
Collecting food waste is a battle against vermin that can be easily won with a few tricks. First find a container that fits your household size. If there’s room to stow it in the freeze, it’s surely not going to attract pests. If you must store it outside the freeze, find a container with a lid that will capture any smells. Chop or cut large chunks of kitchen waste before adding them to the container. When the container is full, empty it into the compost pile. Alternatively, emptying daily will reduce any potential pests during the night. If you don’t generate large amounts of kitchen waste regularly, purchase biodegradable compost pail liners that can be tossed in the compost bin as well to make keeping the container clean much easier.
Collecting brown, nitrogen items can be done seasonally when leaves fall, or by contacting local landscapers who are looking to dispose of this material cheaply. Some municipalities have free wood chips that can be picked up.
Many cities, towns and neighborhoods already have a community garden. There you’ll likely find people who know the value of composting. So why invent the wheel when you have a lot of the knowledge base already?
Community Compost Etiquette
Community + Compost = A myriad of Solutions. Community compost sites are 3-parts personalities and 1-part composting. Be friendly and polite, especially if you’re just beginning, but more importantly if you’re a veteran and want the other people to participate!
Communication is key.
Unless a knowledgeable person is always present, your site needs good signage.
Number your bins 1, 2, and 3.
Create a sign that says “ADD HERE” and place it on the bin you would like to have people contribute to, in which the compost mix is just starting.
When the contribution bin gets full, move the “ADD HERE” sign to another bin and place a sign that reads “DO NOT ADD” to the full bin, to allow it to breakdown.
When bacterial activity has stopped (check by the absences of: pungent smells, heat generation, dark moist areas, or lots of insects) it’s time to let the bin rest. Place a sign that reads “RESTING PILE” and let it sit until you no longer see white, fungi on the browns, or about 4 weeks, after which you can start using your compost!
Caution: Using a compost that is still processing, can be too potent for plants, so make sure the decomposition has completed and the pile has fully rested.
Each bin should contain compost at a different level of decomposition, progressing from the fresh material in Bin 1 to the material that will be ready for your resting pile in Bin 3.
Watering Your Compost
Ideally, you want your compostable material to be somewhat wet, but not soggy. If you see water dripping when you pick something up, you’ve gone too far. Watering and flipping your compost will produce a finished product faster. Not everyone has easy access to water at their compost site, in which case leaving bins lids open on rainy days and/or flipping your compost bins on a rainy day is a great natural alternative to watering directly. Some community garden add moisture through urination events. Check with your local garden director.
Your resting pile can remain as a heap, be transferred to another bin, or be added directly into an unused or dormant garden bed. You can leave your resting pile open or cover it with tarp.
Your resting pile may still have items like apple cores, leaves, wood chips, etc. This is normal, as your compost has not fully matured yet. You can either screen the material or leave it as is. Screening the material will create a finished product faster and create more effective compost. Leaving “noticeable material” intact will limit your compost to a top dressing.
In the fall, apply your RESTING PILE compost directly to unused garden beds. Cover RESTING PILE compost with hay, straw, leaves, or wetted shredded newspaper. This will insulate the compost so that it can continue to break down.
When you are ready to plant, rake away any noticeable material and throw it back into your ADD HERE bin.
Spring is a great time to organize through compost bins, when last year’s remains need to be chopped up and activated. The sooner you can get it going, the sooner your garden will bloom!
Summers require a diligent eye on compost bins. Visit them regularly to make sure they are breaking down, that signs are properly located, and that the garden is well managed. Bring sunblock! Stay hydrated!
When leaves, grasses, and branches are turning brown, it’s time to chop them up and put them in the appropriate bin. Enjoy cooler days working. Don’t forget your gloves.
Community composting can be performed all year long, with appropriate planning.
You can winterize compost bins by adding insulating brown materials on the outer sides of the bins and decomposition will continue inside. Using cardboard, blankets or other materials on the top and sides can also be used.
Proper ratios of greens and browns inside will produce enough heat to continue through sub-freezing conditions. In the event the bin stops during the freeze, it will re-activate once it thaws.
Problem: Not Enough Nitrogen (Greens)
Solution: Get help from nearby residents and businesses. Coffee shops are a good place to start because the grounds the toss out is rich in nitrogen and easy to manage.
Problem: Not Enough Carbon (Browns)
Solution: Start stockpiling your leaves, shredded nonglossy paper, cardboard, woodchips, hay, straw, sawdust, or any other twigs.
Many can be accumulated seasonally for free. Encourage residents to drop off their yard material and leaves in your designated brown source area. This is best done in fall when people have more material to contribute. Some municipalities will drop off wood chips free of charge. Contact your local alderman or landscapers to find out who handles tree trimming or leaf collection in your area.
Problem: Wood Chips Not Breaking Down
Solution: Because woodchips break down slowly, they are best used as top dressing for gardens in the spring. The woodchips will act as a water retention agent on the top of the garden as healthy compost infiltrates the soil.
Problem: Too Much Nitrogen (Odor, Flies, etc.)
Solution: Add more dry brown materials on tops, and sides of compost to contain smell. Make sure your food contributions are adequately covered with enough brown source material. A 2-browns to 1-green is a good ratio, by volume.
Flipping your bins more frequently will also help food residuals break down faster, create more room in your bin, and decrease the likelihood of anaerobic bacteria forming.
Problem: People Not Covering Contributions
Solution: Remind contributors to cover food scraps through signage.
Windrow composting is the most common and most labor-intensive method. Stack raw materials into long piles and turn them regularly with a front-end loader, bucket loader or special compost turner. Delinquent youth short on cash are a good alternative.
Windrow composting doesn’t require source of electricity; can be built in the fields where the compost will be used; and farmers can usually use existing equipment to make and maintain the piles.
On the other hand, farmers must monitor the pile temperature often to avoid odor problems and ensure that the ingredients are composting.
The size and shape of the windrow are designed to allow oxygen to flow throughout the pile while maintaining temperatures in the proper range. If windrows are too large, oxygen cannot penetrate to the center, while if they are too small they will not heat up properly. The optimum size varies both with the type of material and with the time of year. Windrows of autumn leaves should typically be about 8 feet tall and 16 feet wide at the base, but may be built as high as 10 feet in mid-winter. A windrow of grass clippings mixed with leaves will need to be considerably smaller, usually about 5 feet high and 10 feet wide. These sizes are approximate, and may need to be adjusted somewhat.
First is to move material from the outside of the pile to the middle, where it can decompose more quickly. Second goal loosen and fluff the material, so it will be more porous and air can move freely.
Specialized windrow turners are designed to accomplish both of these goals. A front-end loader can do the job as well, as illustrated below. First flip the top of the windrow over just beyond the existing windrow. Second, take the compost from the bottom of the old windrow and place it on top of the new windrow. Let the compost cascade out of the loader, to keep it as loose as possible.
Turning frequency should normally be based on temperature, and should occur whenever temperatures exceed to 140° F, or drop below 90° F (see Temperature Fact Sheet). If the compost is staying in this range on its own, regular tuning can accelerate decomposition by mixing the material and exposing new surface. Leaves may only need to be turned a few times a year, but will benefit from turning as often as every two weeks. On the other hand, grass clippings, even when properly mixed with leaves, may initially need turning once or twice a day. As decomposition proceeds and the compost becomes more stable, frequent turning becomes less important.
If the compost has become anaerobic and smells, turning will temporarily add oxygen but may also stink up the neighborhood. Schedule compost turnings to minimize any negative impacts by considering such factors as wind direction, when people are home, and whether they are likely to be outside or have their windows open. Before turning, try to determine the root of the problem, such as too large a pile, too much water, or too much nitrogen. Remedial action can then be taken as the compost is being turned.
Gather the materials needed to build an “on-the-ground” tumbling composter. An inexpensive and less complicated way to build your own tumbling composter is by creating an “on the ground” tumbling composter, which is simply a container outfitted to hold compost that you “turn” by simply rolling the container across the ground. Purchase or obtain a large cylindrical container with a lid that fits tight. A garbage can works best, and is likely the easiest to find. Select either a plastic or metal garbage can that will hold at least 30 gallons; large containers used for composting hold 55 gallons. Wash the garbage can or container thoroughly if it has been used.
A 1/4” metal drill bit
A 7/8” drill bit
Ear and eye protection
Two 48” lengths of 1/2” metal/aluminum pipe
One 36” length of 1/4” steel threaded rod (zinc plated)
Four 2” long 1/4” bolts
Eight 1/4” nuts
2 elastic bungee cords that are the same length as the can’s diameter
Drill two holes into the lid and bottom of your container using a 7/8” drill bit. The holes you’ll drill into the lid need to be 4” from the outer edge of the lid and directly across from each other, or specifically 180 degrees apart. The holes at the bottom of the container need to be 2” from the edge. You’ll need to place the holes at the bottom in a sunken part of the container’s base because you’ll be sticking metal or aluminum pipes through these holes and you want your tumbling composter to be able to stand upright once assembled.
Create aeration holes all over your container. Drill several holes, about 15-20, into the top and bottom and along the sides of the container using your drill and a 1/4” drill bit. Space the holes evenly. The holes will allow oxygen to flow freely throughout your tumbling composter.
Drill two holes straight through each end of your two metal or aluminum pipes using a 1/4” metal drill bit. Make sure to place them as close to the end of pipes as possible. Doing so will enable your tumbling composter to stand up properly.
Drill two additional holes into each pipe, and then thread your rod through those holes. Once the pipes and connected rod are placed inside the container, the rod will need to rest in the middle of the container. Therefore your two additional holes must measure at half the height of your container. Measure the height of your container and divide that measurement by two. The number you come up with will be the length you measure on your two pipes to determine where your two holes will be drilled. Use your 1/4” metal drill to drill the two holes straight through the pipe.
Before you thread your rod through the new holes, it’ll need to be cut down to size in order to fit inside your container. To do this, measure the diameter of the container at the point where the pipes’ holes will be. You found this point earlier by dividing the height of your container by two. When you come up with the diameter of the container, cut the rod 1” shorter than that, so it’ll fit easily inside the container.
Slide one end of the rod through one of the pipes until the pipe is about 3” from the other end of the rod. Then screw onto the rod two of the 1/4” nuts. Start at the end of the rod that is farthest from the pole. Each nut should be about 4” from each end of the rod. Once secured, the first nut will be right next to the pole, while the second nut will be about 4” from the end of the rod. Once the second nut is secured, slide the rod through the second pipe, stopping when the pipe touches the 1/4” nut. Secure the two pipes by screwing an additional 1/4” nut on the outer edges of the rod next to each pipe.
Secure the pipe and rod structure to your container. Place the structure inside the container and then turn the container on its side to make it easier to thread the ends of the pipe through the two 7/8” holes in the bottom of the container. Secure the pipes by sliding a 2” bolt through the 1/4” holes you drilled into the ends of the pipes, and then screwing two 1/4” nuts onto the ends of each bolt. Stand the container upright and then secure the lid by threading the tops of the pipes through the two 7/8” holes.
You’ll need to drill holes into the length of the pipes just above the lid, so that once bolted the lid will stay secure when you roll it on the ground.
Use a marker to mark the spots where you’ll drill your holes, and then to ensure your holes are even, disassemble your tumbling composter, and lie the pipes flat on the ground when you drill them.
Drill two holes straight through each pipe using the metal 1/4” drill bit, and then reassemble your tumbling composter.
Fill your tumbling composter with composting ingredients and secure the lid. To secure the lid, follow the same method used to secure the pipes to the bottom of the container. Use two bolts and nuts on each side of the bolts, after you’ve filled your tumbling composter with composting ingredients. Slide one bolt through each of the 1/4” holes you’ve just drilled, and then secure those bolts by attaching a 1/4” nut to each end of the bolts. If necessary, you can secure bungee cords over the top of the container by laying them in a crisscross pattern over the lid and securing the cords either underneath the handles of the lid or through a few newly drilled holes.
Test the security of your lid by rolling your new tumbling composter across the ground. Make sure your lid is tightly secured by rolling it across the ground. If dirt begins to spill from around the top, adjust your bolts, or tighten or obtain bungee cords to further tie down your lid.
For this basic compost bin, you’ll want untreated wood. Untreated wood will last for a plenty long time, and the treatment won’t interfere with the composting process or overwhelm helpful fauna. Cedar is a great option.
Four pieces of 2 x 2s or 4 x 4s lumber, cut to 3’ lengths. These posts will serve as the four corners to your square compost bin. Opt for rough, unplanned wood.
8-16 pieces of 2 x 6 lumber, again cut to 3’ length. These boards will make up the walls of your compost bin. Most compost bins have spaces between the exterior boards for aeration; how big you want your spaces to be will depend on whether you use 8, 12, or 16 pieces of lumber.
9 square foot cover, preferably made of solid wood. A solid cover will help maintain a more consistent internal temperature for your compost bin.
Galvanized nails or coated deck screws.
Place the two 4 x 4s on the ground, 3’ apart and parallel.
Lie a 2 x 6 perpendicularly on top of the 4 x 4s, near one end of 4 x 4s.
Measure one or two inches from the bottom of each 4 x 4 so that the 2 x 6 will be level
Nail the 2 x 6 into the 4 x 4s with four nails.
Place another 2 x 6 parallel to the nailed 2 x 6, leaving a 2.5- inch gap between them and nail it to the 4 x 4.
Continue nailing 2 x 6s into place, factoring in the desired spacing, until you reach the top of the wall.
You’ll have two vertical 4 x 4s cross-beamed with three or four perpendicular 2 x 6s. This is 1/4 of your square bin.
Create another side following the instructions above.
Put down two 4 x 4s. Measure 3 inches for your starting point. Then lay a 2 x 6 board perpendicularly over the 4 x 4s, hammering it into place with four nails. Continue placing, then hammering, 2 x 6s perpendicularly over the 4 x 4s — leaving the proper spacing — until you have wall no. 3 assembled. Repeat this for the fourth and final side..
Prop up the two walls parallel to one another and connect the back end of the bin with a perpendicular 2 x 6. As with the previous 2 x 6s, measure off from the bottom, drive in four nails, and space each one evenly. Hammer down 2 x 6s across the back wall of the 4 x 4 until the bin has three walls entirely built.
Make sure to offset the nails you drive into the 2 x 6s so that they don’t collide with the nails driven into the 4 x 4s in the previous steps.
Complete the bin by placing the final boards perpendicularly across the front side. Hammer three or four 2 x 6s across the front face of the bin, following the same routine and remembering to offset the nails.
Cover with a 9 square foot cover.
You can use a tarp or wood for the compost bin, although wood is decidedly better at retaining heat over the long run. If you desire, consider making two small wooden handles and attaching them to either side of your cover for easier placement.
Consider making one or two more identical bins so that you can have a turning unit. One bin contains active compost material; another bin contains processed (or processing) compost materials; the final bin contains soil you’ll use to cover the active compost bin.
Making compost in a garbage bag (also known as anaerobic composting) is by far the simplest way to make compost. It’s free, requires no tools and you probably already have all the materials in your home to start making garbage bag compost. In fact, you might have some processing in an old lunch box that you didn’t even intend!
Warning: This is the slowest composting method.
Two thick black garbage bags; 30-33 gallon bags are a perfect size.
One part of “brown” material (dead leaves, small twigs, wood chips, coffee filters, shredded paper, cardboard or newspaper, straw, old and dried flowers).
One part of “green” (fruit and vegetable scraps, grass clippings, tea and coffee grounds).
One part of soil (including some finished compost to get the process going).
Water enough to dampen the mixture.
Put the brown material in first, followed the green material, then the soil (yes I know, I said no soil earlier and now I'm saying soil) and finally the water. Tie off the bag, making sure no air can enter and put it inside the other black garbage bag. Secure the second bag, put it in a sunny spot if possible, and get comfortable. If you've been thinking of learning Mandarin and reading the classic works of literature, now's a great time to get started.
After eight weeks, check on your garbage bag compost. You’ll know your compost is ready to use when it becomes dark, has no remnants of food or waste and smells like the fresh compost you get at your nursery.
If your compost looks gooey, it’s not done. Wait longer. It could take six months to a year to produce good, usable compost.
Store compost bags outdoors in the summer and in a heated basement or garage in the winter.
Turn your bag once every two weeks to mix up the materials.
Don’t add more material to your bag.
Although you may be tempted to use a biodegradable bag to go “all the way” in your environmentally-conscious garbage bag composting project, you may be in for a rude awakening. Biodegradable bags are often quite thin and may not hold up to the heavy load you’re filling it with.
Plastic storage bins are available just about everywhere, and most of us have at least one of them in our basement or garage. The bigger the storage bin is, the better. The bin you decide to use for composting should be no smaller than 18 gallons. If you are able to obtain a second lid, this would be perfect to catch the liquid that leaches out of the bin. Otherwise, this nutrient-filled liquid will just be wasted.
Drill bit (ideally ½”)
Plastic bin with a lid
Kitchen scraps, yard waste, or shredded newspaper to fill the bin
Wire mesh, if you are drilling large holes
Drill lots of ½” holes all over your bin. (Actually it really doesn’t matter what size drill bit you use, as long as you drill plenty of holes. Space them one to two inches apart, on all sides, bottom, and lid. If you use a large spade or hole-cutting drill bit, you may want to line the interior of the bin with wire mesh or hardware cloth to keep rodents out.)
Because this bin is so small, it will fit just about anywhere. If you are a yardless gardener, a patio, porch, or balcony will work just fine. If you have plenty of space, consider putting it outside the kitchen door so that you can compost kitchen scraps easily, or near your vegetable garden so that you can toss weeds or trimmings into it. It can also go inside a garage or storage shed if you’d rather not look at it.
What to Put in
Anything you would throw in a normal compost pile, you can throw into your storage container composter: leaves, weeds, fruit and vegetable peels, egg shells, coffee grounds, tea bags, and grass clippings all work well.
Anything you put into the storage bin composter should be chopped fairly small so it will break down quicker in the small space. Fruit and vegetable trimmings can be chopped small with a knife, or run through a blender or food processor to break them down. Chop leaves by running a lawn mower over them a few times. Crush eggshells finely so they will break down faster.
Maintain your bin
Every day or so, as you think of it, you can aerate the bin by giving it a quick shake.
If the contents of the bin are staying very wet, or there is an unpleasant odor coming from the bin, you’ll need to add some shredded fall leaves, shredded newspaper, or sawdust to the bin. These will dry it out and help restore the ratio of greens to browns that makes compost happen more quickly.
If the contents are very dry, use a spray bottle to moisten the contents, or add plenty of moisture-rich items such as fruits or veggies that are past their prime.
Harvesting and Using Your Compost
The easiest way to harvest the finished compost from your bin is to run it all through a simple compost sifter so that the large pieces are kept out of the finished compost. Anything that still needs to decompose can go back into the bin, and the dark, crumbly finished compost can either be stored in a bucket or bin for later use or immediately used in the garden. It is also wonderful to use in container plantings.
A plastic storage bin composter can be used year-round, and is a convenient solution for those of us who don’t have space for a large pile.
Do this project outside. The drilling step creates quite a mess.
If possible, toss a few handfuls of leaves or shredded newspaper into the bin whenever you add very wet items to maintain the correct moisture levels.
To turn the compost easily, just give the bin a shake every couple days.
Bokashi composting is the additive of bacteria that decompose organic matter in anaerobic conditions. This is perfect for small, indoor composting because the sealed container traps smells and protects the organic waste from pests.
Food scraps (excluding animal products)
Bokashi bucket (with spicket to drain fluid)
Bokashi mix (wheat brain inoculated with beneficial organisms)
Simply add food scraps to your bucket, along with a handful of bokashi mix over top. Continue doing this until you’ve filled the bucket completely. You may want to use a heavy plate of some sort to help press down the materials in the bucket. This will encourage the development of anaerobic conditions. I simply pressed the food down each time then put the lid on the bucket and everything seemed to work as claimed (i.e. no bad odours etc). Once your system is completely full, simply seal it up and let it sit for a couple of weeks so that it can further decompose. Any time after that you can dig the contents directly into your garden or add them to your compost pile or bins.
If you pile up organic matter, moisten it, and throw a tarp over it to deprive it of oxygen, anaerobic composting will result. Any bin with a tight lid and drainage holes can be used. Even a garbage bag will work. A pile with a tarp over it works well but it will smell
Anaerobic composting requires an entirely different set of organisms and conditions than does aerobic composting. The anaerobic process, which is essentially putrefaction (sorry, but there it is), produces a very acidic environment similar to that in the stomach. Hence the term “digester” used to describe anaerobic processes and to distinguish them from aerobic composting. Actually, the stomach still holds the prize for acidic environments. The pH in an anaerobic digester might dip as low as four but that in the stomach is between one and two.
Both anaerobic and aerobic decay produce heat as a by-product. The temperatures in an aerobic system can become hot enough to kill pathogens or weed seeds. Those in a digester cannot. However, the digester’s acidic environment itself eventually does the trick. Eventually is the key term here. The inhospitable environment takes six months to a year to kill off dangerous micro-organisms.
There’s a second advantage to waiting a full year before using the compost from a digester. Fresh anaerobic material — feedstock that has gone through the initial phase of digestion but hasn’t sat for months afterwards — is so acidic that it cannot be directly applied to plants. Nor can it be dug into dirt where it might come into contact with plant roots. Before it is safe to use, it must go through an aerobic phase that lasts about a month to neutralize its pH. Material that has digested for a full year should be safe for the garden — and it will smell much better.
For this reason, it’s best to have two bins going. When one is full, you can close the lid on it for a year while you deposit waste in the other. By the time you open the first bin, all pathogens will be dead and the composted material will be ready to use.
The simplest anaerobic composter is a plastic bag filled and left in the sun. Most consist of a container with just a single compartment, either placed on cement blocks with a vessel underneath to collect the leachate, or partially buried in the ground. The leachate from a buried vessel will fertilize the nearby soil.
Sinking the bottom of the digester into the ground slows the rate at which leachate drains out of the feedstock and ensures that the contents do not dry out. It also gives worms and other soil organisms access to the contents of the digester, though many will only feel at home after the bottom layer of material has passed through its most acidic phase and the pH starts to level off. Finally, burial helps control odors and makes it almost impossible for pests of any kind to gain access to the bin’s contents.
As with aerobic composting, different methods yield different composting times. The throw-everything-in-a-plastic-bag method mentioned above is roughly equivalent to building a hot aerobic pile. The basic composting is accomplished within a few weeks if the container is in hot sun. A barrel or digester to which you continually add material is more like a slow pile. The stuff at the bottom forms mature compost while the stuff at the top isn’t compost at all.
Material is added to a continuous pile and a barrel digester in the same way. But the compost is harvested differently. With a continuous aerobic pile you throw yard waste and food scraps on top and pull compost out the bottom. There’s no easy way to remove the finished compost from the bottom of a digester. It’s just too wet and sloppy. This is why you eventually need to put the lid on an aerobic system and walk away. This also explains why it’s best to have two bins: one to add to while the other digests.
Bucket with lid or barrel or large plastic bag(s)
Select a sunny site with good drainage. Sunshine helps raise the bin temperature and keep the microbes happy. Drainage is crucial to ensure the correct moisture level. If you have only heavy, clay soils, build a mound of dirt incorporating plenty of pebbles and situate your digester on top.
If your soil has good drainage, locate your digester where the leachate will nourish plants, and where you won’t have too far to trek from the back door. Since it’s best to limit the number of times that the bin gets opened, you’ll need a pail to collect several days’ worth of kitchen wastes.
If you have purchased a commercial digester, be sure to read the directions and follow them carefully. Be aware that if you are using your digester to process pet wastes it is NOT a good idea to situate it near any vegetables or herbs.
Home-built systems can be either large-scale or small-scale. The large-scale systems require a barrel, trash bin or any large metal or plastic container as long as it hasn’t been used to hold toxic substances. Small-scale systems can use a receptacle as small as a pail as in the photograph above. The one absolute requirement is that the receptacle must have a tight-fitting lid.
Digesters produce large amounts of liquid which needs to drain away. The first step in building one is to drill holes in the bottom or even remove the bottom completely. In sandy soil, holes will probably suffice. In heavy soil, an open-bottomed container will more likely provide adequate drainage.
Opinions differ about how deeply a digester should be buried. One site says that a pail need only be an inch deep. But most advise burying half the vessel in the ground. If your soil is sandy, all you need to do is dig the hole and set the digester in place. If you have heavy soil, it’s best to dig out several inches of soil below and around where the receptacle will sit then add pebbles, very coarse sand and organic matter to the soil.
To prepare the hole, return twice as much of the amended soil as you removed. If you dug the hole three inches deeper than you need it, put back six inches of amended soil and tamp it down. As it settles, it will pack down to not quite the original height of three inches. The amendments help create a small, slightly raised and better drained mound.
After filling the hole, set the receptacle in place and use the remaining soil to fill the hole around it. You’re ready to go.
For an above-ground digester, start by drilling holes in the bottom of your bin or barrel. Position them several inches in from the rim. Set the can or barrel up on cement blocks and slide a pan or container, 3-4 inches deep (an old wok works well) under the center of the barrel to collect the leachate that will drain out of the decomposing material. Don’t worry; these holes won’t let in enough oxygen to interfere with the anaerobic process. Depending on the setup, pulling the pan out without spilling its contents can be challenging, even impossible. If that’s the case, use an old chicken baster to remove the leachate.
Filling the Bin
This one is real hard. Throw everything green (grass clippings, leaves, kitchen waste) in a tough plastic bag, filling it perhaps 3/4 full. Press out any extra air and put the bag in the sun for several weeks. Voila! The resulting compost is messy and smells but it’s fairly quick and very easy. Make sure you use a strong plastic bag! If it breaks while you’re trying to carry it to its designated site, there will be no way to scoop up the contents because it’s mostly liquid.
Pails and barrels can be filled with waste as it becomes available. Remember to avoid large quantities of browns such as fallen leaves as digesters are primarily designed to handle kitchen scraps. When the vessel is full, cover it firmly and leave it for two months for quick compost, or a year for fully digested compost.
When all goes well, the only attention required by an anaerobic system is that at some point you stop adding material to it and let it alone. This down time gives the most recent additions a chance to decompose. It helps if you stir them into the contents of the bin before closing the lid.
Opening the lid lets in fresh air and oxygen which interferes with the anaerobic conditions that promote decay. For this reason, it’s best to limit how often you add scraps to the bin. Once or twice a week is best.
Anaerobic systems need very little maintenance, but they should be checked regularly (once a week or so) to make sure that everything is going as it should. Warning signs include excessive numbers of flies, evidence that scavengers have been digging around the base of the bin, and a failure to compost.
Problem: Material Not Composting: You’ll know this is a problem if the pile continues to mount instead of staying fairly level.
If the feedstock doesn’t settle and pack down, one of three things is wrong: the mix is too dry, it contains too much high-carbon material, or there’s too much oxygen in the mix and around it. Sometimes these conditions occur together — woody materials absorb moisture and can trap oxygen — but not always.
Solution: Make sure the material is wet; moisten it if necessary.
Problem: If the bin contains too much high-carbon, woody material such as dry leaves, wood chips or pine needle, moisten it and add a healthy dose of high-nitrogen material such as grass clippings or table scraps, especially fruits and vegetables.
Solution: If the feedstock seems damp enough and doesn’t contain much woody material, the problem may be too much oxygen. This is often the case if you have a small amount of material in a large bin. Poke a stick into the mix here and there or stir it if you can to eliminate air pockets. Add more material if possible. (Beg your neighbor’s table scraps!) Try laying a plastic garbage bag over the feedstock to cut off its contact with oxygen in the bin. Finally, limit how often you open the lid.
Problem: Flies or Odors: A dense population of flies can mean that the mix is either too wet or too dry.
Solution: Keep a bin of sawdust, wood shavings, leaves or other similar material beside the digester and sprinkle a thin layer over each new layer of food scraps. Bear in mind, that these materials are not easily processed by the digester. Make sure that the additions don’t overwhelm the anaerobic process.
DO NOT USE PESTICIDES if you plan to use the compost in the garden.
Fruit Flies: The Santa Barbara County handbook (PDF) says dry conditions encourage fruit flies and advises moistening the contents then covering them with a couple of inches of dirt.
Problem: Soupy Compost: The bin isn’t draining adequately.
Solution: If it’s a home-made container with holes drilled in the bottom, lift it out of the ground and completely remove the bottom. Before putting it back in place, dig up the soil for several inches beneath and around it. Mix this dirt with about a quarter its volume of pebbles or very coarse sand, creating a small mound before returning the bin to the hole.
If you don’t have pebbles, organic matter can be used, but since this decays over time it will not work for as long as the pebbles will. Pine needles, which decay slowly, would be preferable to compost.
Fine sand is not a good substitute for pebbles because in clay soil it can create an almost cement-like compound. This can be avoided by adding organic matter and mixing the materials extremely thoroughly. This is a labor-intensive undertaking.
Sometimes either the labor or the smell involved with removing the bin makes resetting it too awful to contemplate. If this is your situation, try the following: leaving the bin in place, dig out the dirt around one quarter of it, improve its drainage and put it back in place. Don’t remove the dirt from all the way around the bin at once. If the unsupported bin falls over it will create an unholy mess.
Next time you empty the bin completely, improve the drainage underneath it.
Adding dry material to the bin to soak up the moisture is at best a stop-gap move since doing so will slow the anaerobic process without dealing with the underlying problem: poor drainage. As an immediate short-term solution, add an inch or so of dirt to the bin.
When is it finished?
Say you’ve filled and closed an anaerobic digester. How long you leave the lid down depends on at least two factors: how concerned you are about pathogens and how finished you want the compost to be.
If you’re worried about pathogens, or if you want to remove garden-ready compost from the bin, then leave it closed for a year.
On the other hand, if you’re reasonably sure that your materials are pathogen-free, then a few weeks may be all that’s required for the basic composting process to be complete. Just remember that when you remove them, they will be too acidic for plants or their roots. They need to be finished off with an aerobic phase that will neutralize the pH.
To initiate this phase, dig the mix into a fallow area in your garden. The earth eliminates odors at once. As soon as the compost is spread out in soil, oxygen and the whole panoply of soil micro-organisms can go to work on it. After two to four weeks, most of the material should have entirely disappeared and you can safely plant above or in it.
To check whether it’s ready, either do a pH test or look for remnants of the buried mixture. If there’s any rotten smell left when you dig into the soil, wait another week. The aerobic processes will proceed more slowly in very wet soil so allow for extra time if there are heavy rains after you put the anaerobic compost into the soil.
This is accurate but misleading. We can smell the aerobic pile because it’s open to the air. But anaerobic composting takes place in enclosed containers which shouldn’t smell.
It’s true you’ll get a whiff whenever you lift the lid to add new material. But even that can be eliminated by commercial digesters, most of which come with a bag of enzymes that speed decay and help eliminate odors. You can try these enzymes with home systems or just sprinkle some earth over each new layer of material. Quick aerobic compost will still smell pretty awful when it’s exposed to the air which is one reason why it needs to be dug into earth as soon as possible. Slow compost shouldn’t have much smell at all by the time you open the bin.
The various pests that can be a problem in piles are generally a non-issue with anaerobic systems simply because they’re enclosed. Also, the acidic environment is far from inviting. Insects, however, can be a problem. There’s nothing quite like opening the lid of a digester and being engulfed in a storm of flies.
What to Use
This is one of the biggest differences between aerobic and anaerobic composting: meat is strictly forbidden in aerobic systems, but not in digesters where at least some experts say that small quantities of meat are not a problem. However, in introducing animal products, one also risks introducing pathogens which break down more slowly in anaerobic than aerobic systems. If you do put meat in your bin, be sure to let it sit for a full year so that any pathogens can be eliminated by the acidic environment.
Very oily, fatty foods, including margarine, mayonnaise, fatty meat scraps and vegetable oils, should not go into a digester. They’re too much for any composting system.
Compost piles can handle large quantities of carbon-rich material such as dead leaves, straw and even pine needles. Digesters are primarily designed to break down kitchen wastes and green yard waste. Grass trimmings are fine. In an anaerobic system, you don’t have to mix them with other materials or spread them out so that they won’t turn into green slimy mush. In fact, that’s exactly what you want them to do! Green leaves, weeds, old plants and all the usual garden refuse can safely be put into an anaerobic digester in small quantities, but not large quantities of woody hedge-trimmings, wood chips or piles of weeds complete with roots.
Pretty straight forward. Find a rock, turn it over, and put your organic waste beneath it. Leave it there are be patient. In about 3 months, depending on climate, this should be totally broken down.
At this point, you can see that really, it’s for the over-achiever not to recycle your organic waste. Seriously, nature naturally naturalizes organic materials. We have to go out of our way, create giant landfills, order the civic infrastructure and bureaucracies to deliver our organic waste across time and space, all after manufacturing polymers, plastic bags and safely wrapping waste inside for the preservation into perpetuity. Strange, right? Just recycle.
Soda bottle bioreactors are designed to be used as tools for composting research. They are small and inexpensive enough to enable students to design and carry out individualized research projects, comparing variables such as reactor design, moisture content, and nutrient ratios of mixtures to be composted.
The design described here is meant to be used as a starting point only -- please improvise and allow your students to use their own ideas in designing and building their bioreactors.
two 2-liter or 3-liter soda bottles
one smaller container, about 5-cm high, that fits inside the soda bottle
one Styrofoam plate or tray
drill or nail for making holes
duct tape or clear packaging tape
insulation materials such as sheets of fiberglass or foam rubber, or Styrofoam peanuts
fine-meshed screen or fabric large enough to cover top of soda bottle and air holes in bottom half
thermometer that will fit into the top of the soda bottle and be long enough to reach down into the center of the compost
chopped vegetable scraps such as lettuce leaves, carrot or potato peelings, and apple cores, or garden wastes such as weeds or grass clippings
bulking agent such as wood shavings or 1-2 cm pieces of paper egg cartons, cardboard, or wood
hollow tubing to provide ventilation
Using a utility knife or sharp-pointed scissors, cut the top off one soda bottle just below the shoulder and the other just above the shoulder. Using the larger pieces of the two bottles, you will now have a top from one that fits snugly over the bottom from the other.
Place a smaller container (roughly 4-5 cm high) upside down into the bottom of the soda bottle. This will form a stand to support the tray that will hold the compost. You can use any plastic container that will fit inside the bottle and provide adequate support for the Styrofoam stand and overlying compost.
The next step is to make a Styrofoam circle. Trace a circle the diameter of the soda bottle on a Styrofoam plate or try and cut it out, forming a piece that fits snugly inside the soda bottle. Use a nail to punch holes through the Styrofoam for aeration.
Assemble the bottom of your bioreactor by placing the stand into the soda bottle, then resting the Styrofoam circle on top of the stand. Make a mark on your bottle to indicate where the Styrofoam circle sits. Above this point is where the compost will be, and below it is where you want to make air holes.
Make air holes in the sides of the soda bottle in the area below the mark that you made. This can be done with a drill or by carefully heating a nail and using it to melt holes through the plastic. Avoid making holes in the very bottom of the bottle unless you plan to use a tray underneath to collect whatever leachate may be generated during composting. Reassemble the bioreactor pieces, making sure that you have provided sufficient air holes to allow air to enter the bottle and flow up through the stand and Styrofoam circle.
Fill the bioreactor with the mixture you wish to compost. A variety of materials will work, but in general you want a bulking agent to provide air flow plus some vegetable scraps to provide food for the microbes (see following table for some possibilities).
In these mini-bioreactors, composting proceeds best if the bulking agent and food scraps are cut or chopped into roughly 1-2 cm pieces. Soak the bulking agent in water until thoroughly moist, then drain off excess water.
Mix roughly equal amounts of bulking agent and food scraps, then fill your reactor. Remember that you want air to be able to diffuse through the pores in the compost, so make sure to keep your mix light and fluffy and do not pack it down.
Put the top piece of the soda bottle back on and seal it in place with tape.
Cover the top hole with a piece of screen or nylon stocking, rubber banded into place. Alternatively, if you are worried about potential odors you can ventilate your bioreactor using rubber tubing out the top. Simply use the screw-on soda bottle cover with a hole drilled through it for a piece of rubber tubing, which leads out the window or into a ventilation hood.
If you want to eliminate the possibility of flies becoming a problem, you can cover all air holes with a piece of nylon stocking or other fine-meshed fabric. 11. Insulate the bioreactor, making sure not to block the ventilation holes. (Because these soda bottle bioreactors are much smaller than the typical compost pile, they will work best if insulated to retain the heat that is generated during decomposition.) You can experiment with various types and amounts of insulation.
Now you are ready to watch the compost process at work! You can chart the daily progress of your compost by taking temperature readings, inserting a thermometer down into the compost through the top of the soda bottle. Using temperature charts, you can compare variables such as the types of compostable materials, moisture levels, amounts of air flow, and insulation systems.
Because the bottles are so small, you may not end up with a product that looks as finished as the compost from larger piles or bioreactors. You should find, though, that the volume shrinks by 1/2 to 2/3 and that the original materials are no longer recognizable. You can let the compost age in the soda bottles for several months, or transfer it to other containers for curing while starting up a new batch of compost in the soda bottles.
small wood chips
pieces of egg cartons
A worm bin is the best method of composting for you! I hope you’re ready.
(use a combination of one or more dry bedding ingredients listed below)
- Brown leaves/straw
- Shredded paper or newsprint (avoid glossy paper)
- Egg cartons /coffee trays
- 2 Tablespoons - crushed eggshells or agricultural lime
- 1 liter of soil (ordinary garden soil)
- Fill worm bin with dry bedding material. (leaves, shredded paper, etc.)
- Leave water (approximately 2-3 liters) should be left out overnight prior to preparing bedding. This will insure any chlorine evaporates and will bring water to room temperature.
- Do not use water from a water softener - the salt will burn your worms.
- Add water and mix contents.
- Bedding should be the consistency of a wet sponge.
- Pour off any excess water. (Worm bin should be ½ full of wet material)
- Add more dry bedding or water as required.
- Add crushed eggshells/limestone and soil.
Store worm bin in cool, preferably dark place. Worms can live in 5° C - 30° C (40° - 90° F) temperature, ideal temperature 15° C - 21° C (60° - 70°F).
Do not allow worm bin to freeze.
- Start by spreading a layer that is several inches thick of coarse dry brown stuff, like straw or cornstalks or leaves, where you want to build the pile.
- Top that with several inches of green stuff.
- Add a thin layer of soil.
- Add a layer of brown stuff.
- Moisten the three layers.
- Important: Be sure to add the worms to the composter under direct light.
- Worms can be purchased online. Be sure to buy Eisenia fetida species of worms, aka red wrigglers. Earthworms won’t work.
- Simply place the worms on top of bedding. Their natural photophobic tendencies will force the worms into the bedding to a darker, more comfortable environment. Allow the worms to settle into bedding overnight. Start feeding the next day.
- As most worm bins have air holes in the bottom, the worm bin should be raised off the ground. A tray should also be placed under the worm bin to catch any excess liquid. If liquid is dripping out of the bottom, this is an indication the worm bin is too wet. Simply pull back bin contents, and add dry bedding on the bottom to absorb the excess liquid.
As the worms do not like to be disturbed, it is best to feed the worms 1-2 times per week rather than daily. Worms eat about half their weight daily. If feeding twice a week, add 1.5 - 2 lbs. each time. If a lot of food scraps are left over from previous feeding wait a day or two prior to adding additional food.
Bury food a couple of inches under the bedding. Bury the food in a different location each time. Be sure to cover food with bedding. Fruit flies are attracted to exposed food. Sprinkle a handful or so of crushed eggshells on top of bedding about once a week. Eggshells counter the acidity in food scraps. Do not over feed the worms!
Add additional bedding (e.g. leaves, straw, shredded paper, etc.) when it is difficult to bury food scraps. Also helps absorb excess moisture if bedding becomes too wet. Worms generate heat and produce liquid, therefore, condensation will form on the lid.
- Fruit/vegetable peels
- Coffee grounds/filters
- Plant cuttings
- Tea bags
- Crushed eggshells
- Brown paper towels
- Cooked pasta & rice (no sauce)
- Egg cartons/coffee trays
- Leaves/grass clippings
- Beard clippings
- Manure (horse, cow, rabbit)
- Sawdust (from untreated wood)
Worms do not have teeth, they have a gizzard and use the soil to process their food. Chop the organic material into small pieces. The smaller the pieces, the greater the surface area to rot. The worms can process the organic matter more rapidly. Make food into pulp with a juicer if possible.
Do Not Feed Worms
- Meat products
- Animal products
- Animal waste
Harvest the worms when bedding has almost all been consumed (or turned into beautiful black castings) (4-6 months). Do not feed the worms for one-two weeks prior to harvesting. Allow the worms to finish their job. If any bedding or organic material is remaining, simply set aside and add with new bedding. There are several methods for harvesting.
Under bright lighting, empty composter contents onto a plastic sheet. Separate into pyramid shaped piles. Wait 10-15 minutes. Worms are very photosensitive, so to avoid the light, the worms will crawl to the bottom of the piles. Remove the top portion of each pile. Repeat this process until only the worms are remaining. Add the worms to fresh bedding and start vermicomposting process over again. Mix nutrient rich castings in gardens and houseplants.
(If you are not comfortable handling the worms you may want to try this method of harvest.)
Feed the worms on one side of the bin for a number of weeks. This will force the worms to migrate to that side of the bin. Once the worms have moved over to the food source, remove the castings from the vacated quadrant. Replace the castings with fresh bedding (see bedding preparation above). Wait a week or two then repeat the process in the opposite direction, herding the worms into the new bedding.
A black soldier fly house is the best method of composting for you!
5 Gallon Bucket & lid
Drill 1/2 flat drill bit
Piece of wood or other cap
Drill holes beneath the raised band near the lid of the bucket where the handle intersects. This will allow ventilation but not collect rain water. (Drill slowly.)
Drill a hole on the side of the bucket about 2 inches from the bottom. This will be used to periodically drain any accumulated liquids.
Cut and place coconut coir at the bottom of the bucket to help absorb liquid.
Put the wood on top of the bucket and put the lid on the ground, upside down, with water in it. This will prevent ants or other crawling insects from going inside.
Star putting food scraps inside and position the bucket where adult black soldier flies can smell and access the decomposing food scraps.
Black soldier flies like moist, but soaking wet, conditions.
If the smell is unbearable, put less in
Avoid animal products and meats
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