12 top composting faq’s

Shredded, composted leaves partially decomposed

Q. Do I need to buy a bin to make compost?
Q. What can I put in the compost heap?
Q. What does not go into the compost heap? What materials can I not compost?
Q. Can I put weeds in my compost heap?
Q. What’s the easiest way to compost, without all the turning of the heap?
Q. How often do I turn the pile?
Q. How can I speed up the process? Is shredding a good idea?
Q. Can I use compost as mulch?
Q. What about “green manures” and composting them in place by turning them under?
Q. What about vermicomposting, or composting in worm bins?
Q. Where can I learn more about composting?

Q. Do I need to buy a bin to make compost?

A. What method of composting you use should be determined by the volume of material created in the yard (and to a lesser degree, in the kitchen, where vegetable scraps, egg shells and coffee and tea grounds can be collected for the heap, too). I create far too much raw material for a typical homeowner-sized bin-type system, the commercially available kind made of metal or heavy plastic or mesh that are about as big as a washing machine.

I used to have one of those, a metal one that shut tight and thereby kept animals out, to hold my vegetable food wastes, alternating them with layers of garden debris and a little soil or finished compost to get things activated and reduce any chance of unpleasant odors. Now I just dig a hole in the main heap and bury food scraps or sprinkle soil on them to deter pests.

The latest rage is all about lobster-trap-wire bins, meaning really durable mesh (even under the ocean day in and out).

You can make an easy, inexpensive “pen” sort of bin with chickenwire and rot-proof stakes.

My main heap is about 40 feet long and 5 or 6 feet wide, a long, open pile that in composting jargon is called a windrow. In the peak of fall cleanup and leaf raking, it gets to be about 5 feet tall, too, but as the material begins to settle, and eventually to break down, it’s usually more like 3 to 4 feet high.

Garden author Lee Reich has a big garden, too, and he built 15 identical bins from notched, 4-foot lengths of “manufactured wood,” stacked log-cabin-style gradually, a tier at a time, as he adds material. He keeps piling stuff up in each bin to a height of about 5 feet, filling again a few times as the material settles.  He moistens any dry ingredients slightly as needed when adding them. Lee used rot-resistant real lumber to build bins for many years, but lately had turned to the more long-lasting recycled decking “lumber.”

He covers each bin with EPDM fabric, which is typically used for rubber roofing and available at building supply stores. More on Lee’s bin system.
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Q. What can I put in the compost heap?

A. Whatever style of composting system you choose, from a simple, small pile to a long windrow to an enclosed store-bought bin, the key is to vary the kinds of materials that go into the mix. There is no precise recipe; there is just common sense at work.

Green plus brown equals black gold. Layer the two basic categories of ingredients: green ones (nitrogen-rich materials such as grass clippings and leafy green plants) and brown ones (carbon-rich materials like dry, brown leaves or twiggy bits and pieces). Too much of either one will impede decomposition.

I liken successful composting to the combustion that goes on when my car is running smoothly: to ignite, the car needs fuel, air, and a spark. So does the compost heap. The spark is the nitrogen-rich green stuff; the fuel is the brown stuff; the air is supplied by occasional turning of the pile, and water must be available from rain or the hose, so the pile is slightly moist but not sodden.

Too much green stuff (particularly wet things like grass clippings) will produce a smelly heap; spread them around, and toss in a thin layer of soil or old compost to help things get going. I don’t bother with store-bought compost starters; there are plenty of beneficial micro-organisms in good garden soil and some well-rotted leaves.

Too much brown stuff will just sit there (and that includes things that are “brown” chemically if not in color, like piles of orange rinds from weeks of juicing). Chopping up difficult brown elements will speed decomposition; so will aerating the pile, and adding more greens.

Manures from farm animals (not domestic pets) are great additions to the heap, if you can get them from a nearby farm or stable that does not use persistent herbicides or feed their animals any crops that have been treated with these chemicals. Otherwise, you can end up with “killer compost” that will retard plant growth; here’s that terrifying story.

Also remember that unless manures are well-composted in a fast-decomposing (or “hot”) pile, between 120 and 160 degrees F, they will be full of the seeds of what the animals were fed, so plan to let them rot thoroughly in a heap that’s really cooking along. A compost thermometer will help eliminate the guesswork here.

And don’t site the heap in the dark; a position in at least part-day sun is essential to good decomposition.
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Q. What does not go into the compost heap? What materials can I not compost?

A. It’s easier to list what doesn’t go in the heap than what does. Leave out:

  • weeds with seeds on them (pull them before they go to flower and seed, when they can be composted, or “solarize” them to death first in plastic bags; see the next question);
  • weeds that spread even without seeds (like bulbous onion grass), which can be solarized, too;
  • diseased plants (though my expert friend Lee Reich does incorporate some, like this);
  • fats and oils, such as dairy products and meats and fish; bones.
  • animal manures from a tainted source (see the previous answer, or this story on “killer compost” or the U.S. Composting Council’s factsheets on the subject).

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Q. Can I put weeds in my compost heap?

A. This list and how-to from Gardens Organic (England) is one of my favorites on what to compost and not to compost.

Scroll down on that great page (part of the most comprehensive composting site I know of) for the info on weeds/weed seeds, which includes this advice about bagging (to solarize/cook to death) the unwanted weeds, before adding them to the heap:

“Some perennial weeds will be killed in a hot heap; avoid really persistent horrors such as celandine, docks, bulbous buttercup, ground elder and bindweed. Don’t burn or dump these weeds–they are rich in plant foods. Mix with grass mowings in a plastic sack. Tie it up and leave for a few months until the weeds are no longer recognisable, then add to the compost heap. Or send them to your local council green waste recycling facility where the composting methods are hot enough to kill them off.”

The bagging idea is great–a sort of waste not, want not tactic for recycling them versus tossing them into the trash–and you can use a few bags over and again. The weeds I bag instead of adding right to the heap include any with strong runners (like goutweed, or former garden plants I now find too ambitious like plume poppy or ajuga) and any that have started to flower before I pulled them.

My longtime friend and fellow garden author Lee Reich puts weeds into his heap, though many expert sources say never to add diseased or insect-laden materials. Lee’s approach:

“I contend that if you look closely enough at anything, you’re going to find some ‘bad guy’ on it,” he says.  “So my thing:  I put everything into the compost.” Any and all organic material derived from a plant—“organic” meaning living or formerly living with an eye to adding both high-C high-N materials.  He does turn each bin periodically, and again: His piles heat up to a temperature range (140 to 160 F) that helps kill off pathogens or pests.

P.S. — More on weeds (particularly on ID’ing them so you know what you are up against) in this archive on the subject.
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Q. What’s the easiest way to compost, without all the turning of the heap?

A. Long before phrases like “lasagna garden” were making the rounds of the as-yet-uninvented internet, Ruth Stout (author of the classic “The No Work Garden Book”) was layering all her organic materials on top of her soil—sheet composting, as it might be traditionally called—to thwart weeds, reduce the need for fertilizers, conserve moisture and spare herself the work of composting in a conventional heap with all the toting and turning of materials.

Her approach to gardening starts with the foundational principle of applying mulch, mulch and more mulch, and then simply moving it back a tiny bit each year a bit to make room for a row of seeds rather than all that turning and tilling (and weeding).

She says the “aha” came one spring when the plow man hadn’t come yet to till, and she was eager to get planting. She saw that the asparagus (a long-lived perennial vegetable crop) was already up and growing, right through the layers of fallen leaves and such. “I walked over and said to the asparagus, ‘We don’t have to plow for you; why do we have to plow for the other vegetables?’” Stout recalls. “And the asparagus said, “You don’t.’”

Where do you get all that mulch? The garden creates it, or at least some of the raw material that becomes it: spent cornstalks and uprooted pea vines and the like, to which Stout added fall leaves and also bought-in straw or hay (“spoiled” hay was fine, and cheaper; don’t worry about a little decay).

So go ahead: compost in place. I think this is great for vegetable gardens more than ornamental beds, though, for aesthetic reasons.
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Q. How often do I turn the pile?

A. How often you turn your pile will affect the speed at which finished material is ready to be returned to the garden; if you’ve got time, you can escape turning and just let nature take its course (again, nobody’s perfect—and would you like to turn a 40-foot-long windrow every few weeks?). I turn twice a year, in spring and late summer or fall, and extract the lowest layer, where the finished stuff is hiding.

After 20 years of doing this by hand, I recently treated myself to a small tractor with a front-end loader, and the work will be easier from now on. Before using the compost in the garden, I toss it through a homemade sifter, into a wheelbarrow, to cull the stones and sticks and unfinished bits like tenacious corncobs or thick roots. I top-dress my flower beds with an inch or two of the sifted material each spring, along with some all-natural organic fertilizer, and use the rest to top up my raised vegetable-garden beds. Yummy.
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Q. How can I speed up the process? Is shredding a good idea?

A. For years my friend Andrew has been telling me the secret, but I just wouldn’t listen. Like I do, Andrew creates a lot of debris from his giant garden. “Run it over,” he said, whenever I’d complain about the daunting size of my heap. “Just run it over with your mower to pre-shred the stuff.” Well, I finally did.

Facing the overstuffed, impossible-to-manage reality of my 40-by-6-by-8-foot heap, I raked the top 2-foot layer (the still-whole stuff, like last fall’s leaves) onto the ground beside the pile, removed any enormous or woody pieces, got out the tractor, and performed my first act of hit-and-run composting. Wow. What a difference a drive-by makes. Hit-and-run composting! Now I do this in fall when I collect debris, and also in spring cleanup. You could also invest in a shredder meant for this, of course, or an attachment to a leaf blower/vacuum if you use one.
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Q. Can I use compost as mulch?

A. If you want to use compost as mulch later on, I recommend composting leaves separately, in their own pile, as they make a good mulch when partially rotted.  Compost in its finest finished state is more soil-like than mulch-like texturally speaking, so not good mulch (but a great soil amendment).

Leaves can be shredded to speed up the process; this can be done if they are raked into small piles where the heap is to be made and run over with the mower, which works better when they are dry. Then moisten the pile and perhaps sprinkle in some soil or old compost. The leaves can also be left whole, in reusable bags or in a pile, all winter and shredded come spring. Leaf mold, as the rotted stuff is called, is both a great mulch and soil amendment.
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Q. What about “green manures” and composting them in place by turning them under?

A. A month or so before killing frost, the vegetable-garden soil that fed me gets a meal, or at least the promise of one. I sow soil-sustaining cover crops (always from non-GMO, organic seed) as the various food crops are harvested, gradually turning my vegetable beds into mini-fields of winter cereal rye (above) and mammoth red clover for the colder months.

Come spring, several weeks before I plan to plant each area, I’ll cut the grain and legume down or mow them, depending on where they’re located, then turn under the remains—like composting in place, with the foliage and underlying root system decomposing to improve soil texture and fertility.

Cover crops can serve other purposes: Some specialized ones, like various Brassicas, can also provide not just biomass but other benefits like pest and disease control; the subject is much wider than this simple explanation but stated most simply:

  • Grasses (like rye, sorghum-sudangrass crosses, and wheat) add organic matter to the soil very effectively (note that I don’t list buckwheat, another great cover crop, here; that rhubarb and sorrel relative is not technically a grass or grain, though we think of it as such because of how we use it food-wise);
  • Legumes (clovers, cow and field peas, vetch) with their inherent Nitrogen-fixing capability, provide Nitrogen effectively;
  • Brassicas and Mustards (rapeseed or canola; radish; mustard) have proven effective against various nematodes, fungi and insects.

Cover crops—there are varieties for each season and each climate—also serve as a living mulch, protecting the soil from erosion, and thwart other weeds, making the management of fallow garden areas (such as during crop rotations) easier than just standing back and watching undesirable plants take over.

Depending where you live, and what your purpose and timing is, here are some sources of high-quality seed:

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Q. What about vermicomposting, or composting in worm bins?

A. I haven’t written up this topic yet on A Way to Garden, but many years ago I read a book by Mary Appelhof called “Worms Eat My Garbage,” which is still the bible of vermicomposting. This is a great method for recycling food wastes even in an apartment setting, where there is no garden to compost in. One caveat: Worms sold for this purpose may be invasive and even damaging if let loose in the outdoor environment. The details.
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Q. Where can I learn more about composting?

A. Favorite Resources: I am as proud of my compost heap as I am of any part of my garden. It is the archaeological record of my garden past; it is the stuff from which future gardens will arise. I read a lot about, from sources like these: Garden Organic, a 50-year-old British charity; Journey to Forever (don’t worry, not some into-the-bunker survivalist cult); and the vast Cornell Composting archive. The U.S. Composting Council is another mainstay. Dig in.

(Note: Shopping via the book links to Amazon in this article earn me a small commission that I use to buy other books for my giveaways here on the site.)
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  1. AC says:

    Fantastic article. I loved it. I already do most of this so it’s great to know I’m instinctually starting to think like a gardener. Yay!

  2. Margit Van Schaick says:

    Yes!Thank you so much for your wonderful, easily-understood explanation of such an important part of gardening. Loved your “green plus brown equals black gold”! You are such a gifted teacher. Also loved your declaration:”I am as proud of my compost heap as I am of any part of garden”. That is what we all need to say , for the health and well-being of our planet. Thanks again for.this thorough and thoughtful sharing of your knowledge.

  3. Mary Farrand says:

    Composting, is that what you were talking about???? I can’t get beyond the picture of the tulips at this point. Upstate NY (Rochester area) and I am lucky to have my chives and parsley leftovers poking up there heads….just lost out snow…sooo envious.

  4. LJ says:

    Last year for my birthday I asked for a compost bin. We selected one of the drums that has a crank to turn it. Today, almost one year after assembling it and starting the process, I emptied it out and sifted it into the wheelbarrow. I am SO proud of my year of garbage that I had my fiance take a picture of me with my black gold in my hands!

    Composting has been a slightly humbling endeavor. I mean, anyone should be able to rot stuff, right? But it’s a little tricky! Thanks for the tips. There are lots of things here I haven’t been getting quite right. I have a fresh new start as of today, and I’m hoping to keep my ratio of green and brown just right this time!

  5. Mary Moore says:

    Thanks for your comprehensive, easy to understand discussion of composting. I haven’t checked the links yet but will do so and perhaps buy some of the books you mention (if via Amazon, I’ll do that using your links).
    I love the part in today’s blog posting, “From This Bench.”

  6. Nan says:

    Great post Margaret. I’m very proud of my compost heap too! I have a five stage operation with batches in various stages of cooking and finishing at any one time. Recently started composting a bunch of chicken manure. We’ll see how that goes.

    Thanks for the great resources, as usual!

  7. Rebecca says:

    I just joined your blog, Margaret, after reading your article in Parade. I love my garden, and all “my” birds, and I really enjoy reading other’s comments about the same. I have been a lazy composter, but now that I am retired, am interested in becoming more deliberate about it. I recently heard a talk on compost and this speaker said NO to citrus peels…I think she said it killed off *something,* but I can’t recall what. Would you care to comment on this? Thanks.

    1. Margaret says:

      Welcome, Rebecca. The thing with citrus (assuming we are talking more than the occasional orange peel, rather like many of them at once from making juice for instance, is that they are a great example of “too much brown” versus “green” material, which throws off the chemical balance, so to speak. They are slow to break down. Chopping them up a bit first and distributing them around a good-sized heap (not all in one spot and not whole!) makes sense to me.

      It’s all about proportions, the size of the materials (which is why pre-shredding works so well) and so on. Too much of anything=no good. The citrus peels do have oils in them, but again, if you keep it moderate and there is a good mix of other things, it will be fine.

  8. Carole Clarin says:

    I’m so glad that you posted this information but I still have a question! Since I haven’t found a part of my small piece of property and cannot fence it in, I use a cylindrical shaped compost bin with a crank, as well as another bin primarily for leaves. I was unable to get to either during the winter because of all the snow so nothing was added. Should I add the remains of new fruits and vegetables plus the egg shells and coffee grinds and tea bags now, or attempt to remove any compost that may have formed in the bin? I’m in the Massachusettes Berkshires so we still have snow and frozen ground. I felt so guilty all winter throwing away anything that would have gone into the bin-any suggestions about winter composting?

  9. Jaden says:

    Wonderful article! I’ve been having trouble w/my compost – We don’t get much brown leaves (palm trees) and the landscaper guy that rides the lawnmower just cuts the grass without a bag. What else can I use as “brown matter”?

  10. Connie Mac says:

    I am proud of my compost too! Don’t you just love the look on non gardeners faces when you show them the compost just as proudly as you show them your most beautiful garden beds? Thanks for the info on bagging potentially bad weeds/seeds. I’ll install a bag in the utility area of the garden today. Now I won’t be standing weed in hand debating where it should go. Into the bag!

  11. Sara B says:

    We inherited a little 5X5 compost pile from the previous owners and have been topping it off with veggie peels, leaves, and the dirty hay from our housebunny’s litter box (yay, bunny poo!). The bottom layers are very nice and dark and fluffy, but the top is SEETHING with tiny ants! Do you know why?? Is it a bad thing?? Is it time I stop being lazy and actually turn the thing now and then?

    1. Margaret says:

      Hi, Sara. When I have any issues with animals or other creatures in the heap in a major way, I just sprinkle a shovelful of soil on top of the freshly added ingredients or turn the layers, or both. If the pile is too dry, or an unbalanced blend of materials (too much C or too much N all in one area), I get more issues than when it’s slightly damp, well-aerated and a good blend. I wouldn’t worry about ants, frankly; they’re just doing their thing looking for things to eat probably; don’t try to kill them. But certainly turning and maybe moistening and adding some of the finished compost or some soil into the upper layer is good to do.

  12. Karen says:

    How about wood ashes? Add them, don’t add them, or add them only in moderation? I’ve read conflicting opinions about this, so thanks for any insight you can provide.

    1. Margaret says:

      Welcome, Carol. I think a little is ok, but not lots at a time. I found a number of cooperative extension bulletins from around the country (including this one about use of wood ashes in the garden in general, from Oregon State) that stress to SPRINKLE a little in each layer of compost. Meaning: No tossing a whole bucket in, and no using lots unless you have lots of other materials. Sprinkle.

  13. I have a 1500 foot herbaceous perennial garden, like 90% herbaceous. This spring I cut everything down by hand and broadcast in the spot. 95% of the garden stayed where it was. Hollow stems provide nests for insects, and I don’t see ANY of the shreads of stuff under all that foliage. No more buying mulch for me, and no moe composting!

  14. Delores says:

    I started a compost bin last fall with wooden pallets set up as three walls. They have great ventilation and best of all were free. They are working beautifully. We added another bin this summer by adding two more pallets with the third wall being the original bin. So now I have access to two compost bins…just the right size for my garden at this time. I also have chickens so I have kitchen scrapes for the hens and the rest goes into the compost pile. I can’t wait for the ‘black gold’.

    Thanks for the great article.

  15. Martha Pendleton says:

    We have three large compost bins, that my father, and later, my husband made. We compost all of our garden debris as well as produce scraps from the kitchen. But we also compost paper products, like paper towels, napkins, plates and cups even. My husband picks up coffee grounds from local coffee places like Starbucks and incorporates those into our compost to keep it sweet. We also have a source of cow manure that a local rancher sets out in bags for people to take. The whole garden benefits from compost that is produced. The roses LOVE it, as do all of our irises. It is the best thing that we do for our plants. We avoid egg shells that have not been rinsed out thoroughly and any meat products as those things attract rats. But other wildlife love the composting materials. We get a lot of lizards and the occasional garter snake.

    1. Margaret says:

      Welcome, Greg, and thanks for the kind words. So happy to hear you are now officially making compost! It’s one of the most satisfying parts of the garden — transforming “trash” to “treasure” as they say. See you soon!

  16. Dahlink says:

    Loved this post, Margaret. Our neighbor’s daughter is getting married this month and I was thrilled to see that she and her fiance have included a compost bin and compost kitchen container on their wish list!

    Some areas regulate composting (really!) I think in our area an open compost heap is a no-no (fear of rats) and I am sure that the county requires each compost bin to have the requisite worms. A friend and I split an order of officially endorsed worms for our compost (but as far as I know no one from the county has ever come to inspect!) We added a second compost bin this spring and our local barista saves a bucket of grounds for me once a week to help jumpstart the process. We got finished compost in very short order this way. Our soil is heavy clay, but after 20 years of composting we have vastly improved the soil.

    1. margaret says:

      Hooray, Dahlink. And I am jealous of your wormbins! Wonderful, aren’t the little dears? Funny how paranoia re: rats and such prevents people from composting in so many places. As long as you do it sensibly, and cover up any goodies w/some soil or old compost or whatever rather than leave it our in plain view/scent…I have never had an issue. Nice to see you.

  17. Dahlink says:

    I recently picked up one simple tip for collecting the kitchen scraps. I have a great metal container with a lid, but cleaning it out is often a smelly job. Now I put one or two used plain paper towels in the bottom after dumping the contents. Doing this greatly simplifies the clean up! The paper towel disintegrates with the kitchen scraps in the compost bin.

  18. Lorrie Lewis says:

    If I add older (or newer) shredded leaf mold to my perennial garden now, will this invite animals et al to overwinter under there? If I wait til Spring, the pile is too frozen to dig before the newbie plants start appearing. If I wait till the pile defrosts, the plants are too far up to make adding en masse practical. Any suggestions? By the way, John Deere does absolutely the best job of shredding!

  19. carolyn olsen says:

    Thanks for the great info. I have a question about mulching. Hope it’s ok to ask it here. I have a 25 foot hedge of Annabelle hydrangeas, which came with this house I recently moved into. Overhead is an oak tree. I have researched mulching the hydrangeas with composted oak leaves but am wondering if I can just leave the oak leaves around them which have accumulated since last Fall. I raked them out last year and the weeds moved in. Can I just leave the leaves there for mulch?

    1. margaret says:

      Hi, Carolyn. Yes, you can — but with this warning: Sometimes thick layers of matted leaves can be an invitation to rodent pests, such as voles and mice, and there can be some havoc. Also, if the leaves get really thick they can be like a barrier to rain etc. getting through — thought oka tends to break down faster than, say, maple. I like to crumble up the leaves if I can and make a less-matted, more fluffy mulch, but I am all for leaf mold as mulch around shrubberies, yes.

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