Compost Happens: The Brian Rosa Q & A

One of my pet peeves is the idea that “green consumerism” alone will reverse our environmental woes. More than just “buying green,” real change will require behavioral shifts small and large.

Fortunately, composting is a relatively easy change. Chances are, you already separate your food scraps from your other waste. Composting merely requires that you set aside your food waste instead of washing it down the disposal or scraping it into the trash.

In yesterday’s post about garbage disposals, a reader asked about the specifics of composting. So let’s talk about diverting food waste from landfills and sewer lines.
Brian, stirring up materials in a large worm bin

For that purpose, I called on North Carolina’s composting expert, Brian Rosa. In addition to being a good friend, Brian is the Organics Recycling Specialist at North Carolina’s DPPEA.

What’s the best compost bin for beginners?

You don’t need a bin. A pile will work fine. But a bin confines the materials and is more aesthetically pleasing. If you’re in a small urban setting, the Earth Machine will work fine.

What’s the most important thing to do when composting?

Stir it and make sure there’s enough moisture. There should 60 percent moisture throughout the pile at all times. Use the “squeeze test.” If you squeeze it and it sticks together it’s right. If it crumbles it’s not right. And put all kinds of materials in there. Two browns to one green, roughly.

[WF: browns being dry organics like leaves or hay and greens being wet organics like food waste. See the ABC's of Composting section.]

And the most important thing not to do?

Be sure not to ignore it. The more you fool with it, the more it’ll break down [i.e. decompose]. But you don’t have to mix it more than once every three or four days.

Also, don’t dump and run. If you are going to do that, keep dry stuff around—cover it with browns like paper, leaves or straw.

What about composting with worms–what kind of worm bin is best for beginners?

A 10-12 gallon tub with holes for ventilation will handle food waste from two people. You’ll need one pound of worms.

Any particular bin you’d steer people to?

Can-O-Worms is a pretty good brand. And Vermitechnologies Unlimited is a good site for buying worms.

What’s the most important thing with worms?

Keeping the bedding 12 inches deep. The bedding can be shredded newspaper (in 1 inch strips), office paper or junk mail. Just be sure to remove those plastic windows from envelopes.

Also, keeping the bedding moist (70 percent moisture). If you squeeze it and water drips, that’s right. If water doesn’t drip out, it’s too dry.

What’s the biggest worm bin no-no?
They’re pretty forgiving. You can ignore them for a long time, like I do, the poor guys. I haven’t looked at them in about a month. If it starts to smell, it’s because it’s gone anaerobic. It’s probably too wet. Stir it up or add some more dry stuff.

Any parting words (with a composting joke, please)?
Composting is both an art and a science. Most importantly, thought, you need a sense of humus.

Suggested Reading:

Easy Composters You Can Build

Compost This Book (well worth the quarter it costs, used)

Let it Rot!

Worms Eat My Garbage

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  1. Molly
    Posted October 7, 2008 at 12:18 pm | Permalink

    I want to compost, I really do, but I’ve found apartment composting to be more difficult than finding a place for the container. During my short lived composting experiment, I had a perpetual lack of brown material – I thought about hijacking the pine straw mulch from around my building, but figured the maintenance guys would catch on eventually. Then I ran into the how to use it problem. I get very little sun light, so little that the only plants that can live in my apartment are philodendrons, and I just don’t have much use for compost.

    So my questions for apartment dwellers out there who are successfully composting – what do you use as “browns” and what do you do with your compost once it’s ready?

  2. Jonathan
    Posted October 7, 2008 at 2:30 pm | Permalink

    Sorry to hear that you’ve found it difficult, but glad you didn’t snag your building’s mulch.

    One thing I didn’t mention was the whole bokashi thing, which some apartment dwellers swear by. Have you looked into that?

    Another idea–and it’s a bit out there–would be to “import” leaves to your compost bin. I’m sure your building’s maintenance guys wouldn’t mind you grabbing leaves that they’ll have to remove later.

    Any other ideas?

  3. Posted October 7, 2008 at 2:53 pm | Permalink

    For my browns, I use the cardboard rolls from toilet paper, paper towels, wrapping paper, etc. You can also use lint from your dryer, pet hair, people hair (from brushes and such). I found that a regular home office shredder works great for getting the cardboard products down to a manageable size.

  4. Posted October 8, 2008 at 10:10 am | Permalink

    hello Jonathan sir,

    I’m a school student from India. A few of us are into a project for using the food waste in our school for composting and to use the manure for other purposes. We are a school of around 650 people ranging from the age of 14-17.

    Could you give us any advice on the size of a suitable compost pit, and any other measures for this project to be successful? We are a group of 5 people, all in 10th grade. Thanx a lot!!!

    The Peacelover

  5. Allison
    Posted October 8, 2008 at 7:10 pm | Permalink

    We’ve been composting for almost 9 months. Everything looks mushy and brown. I turn it and stir it 2 or 3 times a week. I use a bin (at least 3 cubic feet, which was what I read was essential for holding in enough warmth) with holes punched in the sides and bottoms, and I put in foods–except for oils/fats, dairy, meat–and also browns which are usually shredded paper, cardboard, dryer lint. I think I have a good ratio of carbon to nitrogen. And it seems to give off a lot of heat when I lift the lid to stir. We live in Fla. so it gets a lot of warmth and sun. But here’s my question: How in the world do I know when it’s “done”? I keep adding new stuff, but should I stop doing that at this point? I keep expecting to see what looks like soil, but the brown matter clumps together and looks so moist, I can’t imagine it would serve as soil. Please help me know if I’m doing this right and if it’s ready to be used.

  6. Posted October 9, 2008 at 10:27 am | Permalink

    Just read your post. Several questions before I can really answer your question.
    Are you planing on composting food waste from the group of 5 or is the group of 5 going to compost food waste from 650 ?
    If for 5. You can figure about 1- 1.5 Lbs per day per person. More if you are vegetarians and/or coffee drinkers (coffee grounds). You will have to balance the food waste or nitrogens (green)(include: food scraps, manure, grass and weeds) with at least twice as much brown (carbon) by volume. Browns or carbon materials include; leaves, straw, saw dust, wood chips, and paper products.(if you can’t recycle it, compost it)The pile should be at (like Allison from previous posting was relating to) least 3′ x 3′ x 3′ can be larger but not smaller. This is what they call criticle mass. The pile is large enough to hold the heat generated by the process, but not so large that oxygen cannot migrate to the center of the pile.
    Stock pile your carbon material and as you take out the food scraps to your pile, cover them with carbon.Continue this until you have enough material to make critcle mass. At that point, stir and mix all the materials together and add water to pile. The moisture content should be 50% – 60% moisture.
    * Note: Squeeze test; squeeze a handful of material, if water squeezes out – too wet, if the handful crumbles and falls apart – too dry, if handful sticks together – just right !
    Once you have the correct amount (2 parts) of Carbon (browns)and (1 part) Nitrogen (greens)
    Within 24 hours, the center of this pile should be 120 F – 135 F. If the pile is not hot – something is off ! Either too wet – add dry material and mix
    Too dry – add moisture
    Or not enough nitrogen – add more food scraps or grass or …
    Once the pile heats up, leave pile for at least 3 days. 3 days at 133 F, the center of the pile is finished (composted; organic matter is consumed by microbs, weed seed and pathogens are killed off)
    After 3-4 days, mix pile, introduce outside of pile into the center, add water. Cintinue this process for 3 – 6 weeks. The pile should heat up each time for the first 4 or turns. The pile will reduce in size by 405-60%, and the material will look like humus. You should not reconize much of the material in the pile – maybe a stem or twig or two !

    If you are considering composting for 650 students – give me a call. we can go over several options available. If you are in North Carolina you will need to get a permit from NC DENR, Div of Waste

    Good Luck,

    Brian Rosa, Organic Recycling Specailist, DPPEA

  7. Posted October 9, 2008 at 10:48 am | Permalink

    Sounds like you are doing the things to do ! How about the moisture content ? see above posting about sqeeze test ! At some point you will want to stop feeding the pile and finish it off. When done you should see a 50% reduction in volume, dark brown humus like material, should not reconize that much of the stuff left, maybe a few leaf stems and twigs !
    Brian OGS, DPPEA

  8. Posted October 9, 2008 at 4:09 pm | Permalink

    Brian Rosa is my hero and he’s an intense cat who knows his composting! Listen to him folks…he’s THE man on this topic!

  9. Lynn
    Posted October 10, 2008 at 1:21 pm | Permalink

    I live in a tiny box of an apartment with no outdoor space, but I have gotten my composting up and running again. First, I have an electric composter (Naturemill). It is about the size of an overlarge CPU, so it does not take up much space. Also, it uses very little energy (small amount of heat and a fan to keep things aerobic), makes very little noise (only a whirring sound as it stirs the compost for a minute every few hours), and is very convenient to add any organic waste to (up to 5 lbs/day including dairy, fats, and meats, as well as the litter waste from my two cats–it is the pet-friendly version. The temp. is maintained within 120-140 deg. F, so it kills any potential pathogens). Once it is mostly broken down, it is transferred to another tray within the unit for curing (a couple of weeks for outdoor use, a few months (someplace else) for indoor use). It is a great composter for people who do not have an outdoor area. I will be starting a small worm bin again to compliment the use of the Naturemill.

    As to how I use the compost when I have no yard. I use some for my indoor garden. The rest, I give to friends and family who need compost for their garden (but who are not composting themselves). Also, there is an empty dirt lot near where I live, so I am making plans for using some of my compost to enrich that severely abused soil and plant some seedlings and seeds there this winter and spring. If no one tears the plants out, then I hope to help make that area look much nicer and be more hospitable to local birds and beneficial arthropods. Even better, I can grow some food-producing plants for harvest that my itty-bitty garden cannot grow (like luffa gourds or sunflowers)

  10. Mimi W.
    Posted October 14, 2008 at 1:40 pm | Permalink

    While information on “How to Compost” is useful to many, I would like to see a national campaigne about how compost just happens. If you have a yard and trees, every fall make a big pile of leaves and leave it alone. In a year, it will be a small pile of leaves. (I think this is called leaf mold and is very popular in England.) Make another big pile of leaves and leave it alone. The third year, your first pile of leaves will be lovely compost, your second pile will be leaf mold, and you make a third pile. You don’t need to do ANYTHING and it’s even easier than bagging the leaves and putting them out to fill up the land fill. Many, many people will tell you that they don’t have the time or interest to do “all that stuff you need to do to compost.” We need to let people know that composting doesn’t need to be complicated or time consuming.

  11. Jonathan
    Posted October 14, 2008 at 2:11 pm | Permalink

    Mimi W., you make good points about letting leaves compost and how silly it is to truck them off to a landfill. I’m guessing you write from experience.

    While this model of hands-off composting sure works with leaves, I’m wondering what happens when you add food waste to the mix? Because once that stuff goes anaerobic, it releases methane (bad for the environment and our noses!). Have you incorporated kitchen scraps into your leaf piles?

  12. Darcie Vandegrift
    Posted October 18, 2008 at 11:22 am | Permalink

    While I appreciate the formulas for making compost and all the “don’ts” to follow, my family and I have successfully composted for years doing lots of “bad things.” Dump and run? Yup – my 11 yr old son takes out the scraps from the kitchen (he’s often really messy) and I usually stir on the weekends (or even once a month.) Our stuff freezes throught the Iowa (urban) winter out there, then quick starts in spring when the most holy of days – the return of worms – happens. We mix in grass, weeds, and leaves at times, but other times not. And I have great compost at the bottom of the pile that I use all season. And for whatever reason, we’ve never had a problem with anaerobic compost.

    I appreciate the experts and I use their tips all the time, but please don’t avoid composting because it sounds too complicated. You can do it simply and still get a usable finished product

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  1. By FilterForGood: Home on April 22, 2009 at 9:03 am

    [...] That basically leaves the vermicomposting. But this too seems to have its downsides. For one, Can-O-Worms — the vermicomposters recommended by Brian Rosa, composting expert,** costs $130 — a little more than I was planning to spend, though I might be able to get over that. [...]

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