In honor of election day, I’m re-using a bunch of political yard signs to build a small outdoor shed. The Coroplast used for high-end campaign signs is far too good to be tossed out just because somebody lost an election.
I’ve decided on the following method of construction:
It’s every bit as complex as it sounds. Continue reading Post #1897: Re-using political yard signs. Composting shed, Part 2
Today is the day when a whole lot of campaign signs go straight into the dumpster. Along with the political aspirations of half the recent candidates,
Which is a pity, really. (The signs, I mean.) The best of those signs are made to last a long time. We really ought to do better than treating them as a single-use disposable.
So I suggest that the first Wednesday following the first Monday in November be declared Campaign Sign Recycling Day. In keeping with that, today is a good day for me to make something useful out of some dead political yard signs.
This post is the theory. Next post is the actual assembly.
Source: Coroplast, Inc.
Campaign yard signs come in several varieties.
Cheap campaign yard signs aren’t re-usable in any obvious way. Some are coated cardboard, on some sort of stick. Some are a printed plastic sleeve that fits over a three-sided wire frame. For both of those, the metal frames (if any) can be recycled. But the signs themselves aren’t good for much. Far as I can tell, once they’ve served their purpose, they’re trash.
By contrast, high-end campaign yard signs are Coroplast(r). That is, corrugated plastic sheets — two sheets of plastic bound together with thin plastic channels. As pictured above. Effectively, they are built like corrugated cardboard, but plastic.
These sheets — typically made from polypropylene — have a surprising amount of structural integrity. Much like corrugated cardboard, they are quite resistant to bending or folding across the corrugations. This means you could use a single thickness of Coroplast to build light-duty objects, and multiple thicknesses to build heavy duty objects.
These also stand up well to being used outside. The ones forming the sides of my oldest raised beds now have more than five years of cumulative outdoor exposure (first as yard signs, then as raised bed sides.) Only this year did they begin to show brittleness from all that sunshine and weather. (And if I’d cared to keep them painted, I probably could have avoided that, as most of the damage is from exposure to the UV in sunlight.)
I’d say that the biggest downside is that these can’t be glued together. (Or, at least, not well, or not easily, using conventional glues). The underlying material (typically, polypropylene) just doesn’t stick to much. And the ink coating — the printed message — further complicates things.
Near as I can tell, most people who make DIY projects with Coroplast sheet opt for some sort of mechanical fastening. That can be as simple as cutting slots and tabs, so that sheets fit together. Than can include melting sheets together, in places, to form a sort of plastic rivet. Or can include using actual metal fasteners (bolts, washers, nuts) to hold the plastic parts together. Or staple or nail them into a wood backing.
(The big exception being model airplane enthusiasts, for whom gluing coroplast is the only practical option. That said, after having read one or two sites discussing that use, I’m convinced that gluing up Coroplast is not something that you’re likely to get right the first time.)
There are chemical methods that might, in theory, hold these sheets together. Some are specialized glues specifically designed for this sort of application. All of those appear to cost an arm and a leg, at least for the quantities that would be needed to build (e.g.) a piece of furniture. And then there’s solvent-welding the polypropylene (PP). That is, finding a solvent that will dissolve PP, dissolving some pieces of PP in that solvent, and then using that as if it were glue. I strongly suspect that either approach — specialized glue, or DIY solvent-welding — requires a nice clean PP surface, involving a lot of complicated surface preparation, and that the ink firmly bonded to the typical campaign sign would interfere with that.
Dare I say this? Even duct tape is iffy. The same factors that make it hard for glue to stick, make it hard for tapes to stick. And surface preparation for taping is not easy (e.g., lightly torching the PP surface). All told, taping or gluing this stuff seems like a lot of work, on the off chance that you can get something to stick firmly.
The upshot is that I’m going with mechanical fastening only.
I find most plans for upcycling or recycling of materials to be of little value. Most involve using small amounts of materials. Most involve creating something for which there is a very limited demand. The results tend to be more of a novelty than a way to divert significant amounts of material from the landfill.
Contrast that with using campaign signs for the sides of raised garden beds. That used up a lot of material, slowed down the inevitable progress toward the landfill by years, and avoided consuming considerable amounts of virgin materials.
In this case, I have a stack of roughly 35 campaign yard signs, or about 100 square feet of Coroplast sheet. Pre-cut into neat 2′ x 1.5′ pieces. So I’m looking for a project that will use up just about that amount of material, and give me something useful in return.
Source: Google search
In Post #887, I did up a quick summary of the various construction methods used to create corrugated cardboard furniture. I’d guess that just about anything you could build as corrugated cardboard furniture could also be built out of Coroplast.
So if you are stuck for ideas, you can look up cardboard furniture plans. As long as they don’t depend critically on glue, they ought to work with Coroplast.
As I see it, the main approaches to creating weight-bearing structures for cardboard furniture are:
Simple stacked sheets.
Source: Homedit.com
Folded beams
Source: Time, inc.
Structural grids (with or without surfacing materials):
Source: Planet Paper
Source: Storage Techniques for Art, Science, and History
It seems worth mentioning that a lot of lightweight commercial bins and totes are made from folded and fastened sheets of Coroplast. It’s such a common use that there’s even a market for used Coroplast bins and totes.
You can find lots of different plans on the internet for constructing Coroplast totes, bins, boxes, and so on. They all boil down to folding a sheet into a box shape, and then somehow fastening it together at the corners. In the example pictured above, the author constructs a sort of “rivet” out of hot glue, and uses that to fasten the corners mechanically (reference).
Here, I’m shooting for something larger, to use up more Coroplast signs.
Source: Builder Bill
I’m going to turn my pile of used Coroplast into some structural integrated panels or SIPs. In this case, the SIPs will be flat, rectangular wooden frames, faced with coroplast sheets, and filled with … probably scraps of insulating foam board.
Like a hollow-core door, if you’ve ever dealt with the insides of one of those. The entire frame around the rim is solid wood, and so has enough strength to hold fasteners and hinges. But the broad flat surfaces are just thin, rigid sheets backed by some hollow, honeycomb-like structure.
As long as those rigid face sheets stay firmly in place, the entire unit ends up being quite strong, given the light weight. Far more than you might reasonably expect. This is why (e.g.) you can easily use a hollow-core door as a table-top, even though the individual face veneers are far too flimsy for that use.
I think this takes good advantage of the strengths and weaknesses of Coroplast. And it allows me to connect the Coroplast to the structure using a (hardware) staple gun, which is about as fast and as lazy as it gets. But all the connections subject to high point loads — the sort of connector that would pull out of a thin plastic sheet — can be made through the solid wood edges.
And it’s generic. I’m going to use this to build a little knock-down insulated shed for my composter. But nothing would stop you from (e.g.) building furniture this way. Bookshelves. A larger shed. A lightweight travel trailer. Anything that can be made from rigid flat panels can be made this way, within the strength limitations of the materials.
At this point, putting the composter cover together is just a matter of connecting the panels made in just above.
Ideally, I’d like to have “knock down” construction — something that can be easily disassembled and re-assembled without tools. (That way, I can store it away easily during the off-season). But in the end, this is only going to take four long screws to hold it together. So I’m just going to screw it together.
How this actually goes together is going to depend on what scraps of lumber I build it out of.
In this post, I figured out how I’m going to use up a lot of 1.5′ x 2′ Coroplast campaign signs. My proposed method is to build a bunch of “structural panels” out of those signs. That is, thin wood frames faced front and back with Coroplast sheets. And then use those rigid panels to build a structure.
This approach:
All I have to do now is to make that happen.
I’m now going to test that, by building a winter cover for my composter, using that “structural panel” method. Assuming all goes well, the construction of that should be documented in my next post.
Normally, about this time of year, I’d start burning my way through two cords of wood, over the course of the winter.
This year, I’m not.
It’s complicated.
I went through the biggest global environmental problem in heating with wood back in Post G22-058.
In a nutshell, when I burn firewood for heat, the C02 that goes up my chimney came out of the air an average ten years ago. For that reason, firewood is very close to a carbon-neutral fuel, when viewed over (say) a decade of time. Over that time period, atmospheric C02 is neither increased nor decreased by the process of growing wood, then burning that wood.
As opposed to say, burning natural gas. Typically, that was produced some time in the last half-a-billion years or so, and trapped underground. The C02 from that source definitely adds to the current level of atmospheric C02.
But along with wood burning comes soot. And even though that soot resides in the atmosphere for just a brief period (typically, two weeks), soot is incredibly effective at capturing the heat from the sun. Dispersing a microscopic black powder through the atmosphere allows the atmosphere to absorb more light energy? Who would have guessed that?
Source: Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza,
T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United
Kingdom and New York, NY, USA.
Back in 1995, nobody quite knew what the net effect of soot was. Even through 2014, estimates were uncertain enough that the confidence interval around the point estimate included zero.
That said, you have to go with the most recent evidence. Based on the 2014 5th report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), I estimated that the warming effect of the soot from my wood stove was just about large enough to offset any benefit from wood burning. That’s the gist of in Post G22-058.
And that’s why I skipped the firewood purchase this year.
The IPCC sixth summary report was released in its entirety earlier this year. So it’s worth taking a peek at that, as the estimate for black carbon involved a lot of uncertainty.
(First, though I have to note how different the public debate is now, for the IPCC 6th report, compared to nine years ago, for the 5th report. For the IPCC 5th report, climate-change denialists went over it with a fine-toothed comb and found an actual substantive error, in a sentence, in a section of the technical portion of the report. This had to do with the rate of melting of Himalayan glaciers. And, as is their habit, the climate-denial industry then proceeded to play the game of This Changes Everything, So Believe Nothing You Have Heard. For the sixth report, by contrast, the release was uneventful, and nobody tried to fabricate some made-up stink about it. It’s almost as if everyone with sense now realizes that climate change is real, man-made, and causing problems. And so there is little value in trying to generate new disinformation, because those who still deny that climate change is a real threat are more-than-satisfied with continuing to believe disinformation that was debunked decades ago.)
Interestingly, they’ve revised their estimate of the warming impact of soot way downward, compared to the 2014 report. (Though still within the 95% confidence interval of the 2014 report).
The best estimates of ... attributed to ... black carbon is substantially reduced. The magnitude of uncertainty in the ... due to black carbon emissions has also been reduced relative to AR5. (Section TS.3.1)
Source: Page 42, IPCC, 2021: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2391 pp. doi:10.1017/9781009157896.
And, in fact, it looks like the estimate of the warming impact of soot is back about where it was in 1995. Which is about when I decided it would minimize my global warming footprint if I burned wood for (at least some of) my home heating.
Source: Page 92, reference cited just above.
Without getting further into the details, at face value, the upshot of this most recent change is that heating your house with wood, in a modern air-tight low-emissions wood stove, probably offers significant net benefit in terms of global warming footprint. Based on this most recent estimate of the impact of the resulting soot. Assuming I did my calculations correctly last year.
This year’s air pollution alerts from Canadian forest fires have made me a lot more sensitive to the issue of air pollution from wood fires. In the past, I’ve just turned a blind eye to that, mostly because as far as I can tell, I’m the only person within blocks that actually burns wood for heat.
Air pollution from an isolated wood stove does not have the same public health implications as air pollution from Canadian forest fires. That’s because you have to be in the exhaust plume from my stove to be affected by it. By contrast, you were breathing Canadian soot no matter where you were, and no matter when. It’s the difference between a brief exposure, walking past my house (say), and breathing it 24 hours a day.
So, really, it’s more a question of what I’m doing to the air that I and my neighbors breathe. And for that, the key question is how particulates generated by my wood stove, at my property line (i.e., entering the public domain) compare to the particulate levels we saw during the Summer 2023 air pollution alerts?
I suspect that the only way to tell, with this one, is to measure it. Which I will, the next time I light a fire in my stove.
For now, let me work through the basics, given that this stove is EPA rated to produce no more than 2 grams of soot per hour. A good round number for “too much soot in the air” is, say, 100 micrograms per cubic meter for total particulates. That would trigger an “unhealthy” reading for PM 2.5. To get down to that level, an hour’s worth of soot from my stove would have to be diluted into … 20,000 cubic meters of air per hour.
Or about 333 cubic meters of air per minute. In order to dilute the smoke from my wood stove down below the “hazardous” level for particulate matter. That’s a cube of air roughly 18′ on a side. That seems like a high-but-plausible rate of dilution.
There is also a sense that if you can smell wood smoke, you are breathing in pollutants. And that may well be true — the smell must come from somewhere. That said, a quick look at some scholarly papers suggests that there isn’t a tight correlation between the smell of smoke and the density of particulates in the air. (As evidenced, I guess, by the Canadian forest fires, where there was no smell of wood smoke in the air, but particulate levels were high).
So, before I even lay my first fire of the season, and get out my recently-purchased air quality meter, I’m guessing that this is an open question. I can surely smell wood smoke, at ground level, at least part of the time that I’m buring wood. The next step is to measure it and see if I’m pushing unhealthy levels of particulates out into my adjacent neighborhood.
My roll-up solar air heater is putting out about 2200 watts of power, in the form of heated air, in the mid-day October sunshine, 37 degrees north latitude.
But absent some sort of magic, that’s not enough. Not on its own, anyway. To keep my composter working through the winter, I’d have to build an insulated box for it, and pipe the hot air into that box.
I’m not even sure that would work. And even if it did work, I’m not sure it’s worth the effort.
Continue reading Post #1866: Winter composting, take 2, using an indirect solar air heater.
It takes a surprisingly small depth of fall leaf litter to provide an adequate supply some key nutrients for your vegetable garden. Leaves-as-fertilizer is just another reason to #leavetheleaves.
It may be difficult to believe, but some versions of the Bible actually omit that line from Ecclesiastes 3.1-11.
I’m getting ready to plant a 4′ x 8′ area with hard-neck garlic, for harvest next year. Plant the cloves in the fall, once the soil is good and cold, and, with any luck, they’ll come up next spring and give you nice big heads of garlic by mid-summer. I wouldn’t know, because, typically, I plant them too early, by contrast, and they’ll sprout now. They may survive into next year, but I can tell you from experience, the result will be puny, unusable heads of garlic.
(Weird garlic fact: If you plant bigger cloves, of a given variety, you’ll harvest bigger heads of garlic. I’ve seen this result replicated enough times that I’m fairly certain it’s true. E.g., Red Gardens stumbled across this effect, but you can find it in many scholarly sources as well. This is arguably the only reason not to plant grocery-store garlic. As it turns out, “culinary grade” garlic, found in the grocery store, has smaller cloves than the garlic reserved to become “garlic seed”.)
The lowest recommended fertilizer application I found, for commercial garlic growing, was from Cornell University. Their most recent study said that that 50 pounds of nitrogen per acre would be sufficient, and that yields did not increase if you added more than that. Essentially, you should expect your garlic to pull that much nitrogen out of the soil, so that’s what you need to replace.
I could supply this using 30-0-0- lawn fertilizer. To be clear, I think that putting lawn fertilizer on your lawn is crazy and environmentally destructive. But it’s a good source of nitrogen. I own a 10-pound bag of it. I’ve owned that particular bag for maybe a couple of decades now.
To supply the complete nitrogen needs of by 4’x8′ garlic bed, I would need four level tablespoons of lawn fertilizer. Like so:
If nothing else, this shows you why you shouldn’t just wing it, when it comes to concentrated chemical fertilizers. You only need trace amounts. That’s such a small quantity of material that it would be difficult to spread that evenly over the bed.
But, in fact, I’m going to supply this using fallen leaves. Because a) why not, and b) the leaves serve as both mulch (before they decompose) and fertilizer (after they decompose).
How deeply must I bury that bed in fallen leaves, to supply all the nitrogen the garlic requires? Take a guess:
The answer is C, a few inches. In this exact calculation, the answer is that about half-an-inch of fallen leaves should be adequate. Surprise. That’s based on leaf litter containing about 1% nitrogen by weight, as shown here.
To double-check that, I can start from an alternative data source. At a mean of 10 grams of nitrogen per kilogram of leaves, I would need about 1.5 kilograms, or maybe 3.5 pounds of leaves, to supply the required nitrogen. Same as the calculation above.
Source: American Journal of Horticultural Science.
Unlike the water-soluble lawn fertilizer, where excess will run off with the rainfall, it’s probably close to harmless to err on the upside with leaves. Some sources suggest fertilizing at up to three times the rate recommended by Cornell. And, to be sure, the actual N content of my particular leaves might be less than average. And maybe there’s some catch here, such as the N in fallen leaves being less readily available than the N in commercial fertilizer. So, in theory, if I wanted some insurance, I could pile (say) three inches of leaves on that garden bed let them rot over the winter.
The term of art for this — for letting a relatively thin layer of leaves rot over a large area — is sheet composting. By calculation, I can easily supply the required nitrogen for my garlic by sheet composting my fallen tree leaves on that bed.
In fact, fall leaf litter contains so much nutrient, in total, that in well-watered climates, centralized leaf collection reduces nutrient runoff into the surrounding surface water. So says the USGS, in this piece. I count that as the sole potential environmental benefit of centralized leaf collection.
During the growing season, it’s better to compost the leaves first, then add that to the bed. The act of breaking down the leaves temporarily draws nitrogen out of the very top layer of the soil (explained per this reference). But by the time the garlic needs nitrogen in the spring and summer, that thin layer of leaves will have already broken down.
Finally, this year, I’m going to give my garlic a little sulfur. If I can figure out how to do it.
It seems like a not-unreasonable thing to do.
First, sulfur is a key component of allicin, the chemical that makes garlic, garlic. Some research suggests that sulfur-deficient soil results in garlic with less allicin, which I think has to mean, less garlic-y. And, possibly, smaller bulbs, to boot. I see no point in growing small, bland garlic bulbs.
For sure, garlic withdraws sulfur from the soil. Whether or not the soil is actually deficient, it seems prudent to put the expected amount of the sulfur withdrawal into the soil head of time.
By my estimate, if all goes well, I’ll need to replace about a gram of sulfur per square foot of garlic bed. Or, in this case, 32 grams of sulfur, just bit over an ounce of weight, in the 4’x8′ bed I’m planning to use. That’s assuming I get lots of garlic out of this patch, two 100-gram bulbs per square foot. More realistically, this is an upper bound on what I need.
The hard number is that garlic is about 0.5 percent sulfur, by weight (this reference). The naive assumption is that I can grow 6400 grams of garlic in 32 square feet of bed. (Then 0.5% of 6400 = 32 grams). That seems to ballpark with other published estimates.
Source: Espoma.com, used without permission.
Turns out, I own a big, almost-unused bag of Espoma Holly Tone. Why, I cannot recall.
Which probably explains why the full bag is still here. It’s a result of a reverse-Darwinism, survival-of-the-un-fittest process. If the duds are allowed to linger, they eventually dominate fill your storage space, for the simple reason that they don’t get used. Likely, whatever I bought this for, long ago, did not pan out.
Will it work here, to give me my 32 grams of sulfur? Because I sure won’t mind using some of that up. To get 32 grams of sulfur, I need about a pound and a half of Espoma Holly Tone.
That seems like a lot, and that’s a problem. If I do that, I add too much nitrogen. The Espoma mix is 4% N. When I do the math, that 1.5 pounds of Espoma H-T- provides 0.06 pounds of N, or about twice what the Cornell-derived estimate suggests that the garlic needs.
Given that I am going to cover this bed in fall leaves, I may have to buy something else for sulfur. Looks like the Espoma H-T can provide enough sulfur, but it brings along too much N (etc.) that I’d rather provide by sheet-composting leaves.
Maybe a reduced amount is called for. Maybe some different product entirely. We’ll see. There are still things about sulfur as a soil amendment that I clearly do not yet grasp.
Finally, I have to find a cheap test for soil sulfur, if such exists. For now, I’m still feeling my way through the whole sulfur-for-garlic thing.
Am I going to rake my leaves to the curb this year, for vacuum pickup by the Town of Vienna. No.
Do I need to add chemical fertilizers to my spring garden? No.
Are those flip sides of the same coin? Yes.
Add sulfur to garlic bed? Not clear yet.
Yeah, no joke, that’s what this one is about.
After N pages of thinking it through, my solution is to toss two layers of clear plastic over my tumbling composter (below), and hope it buys me a few weeks.
As I have learned from Watch Wes Work, it’s only temporary, unless it works.
It’s a long and winding road, to end up with that. But sometimes you have to assess the options, even if nothing new jumps out at you.
With my redneck double-glazing, the plastic surface of the composter reached about 110F, on a roughly 70F day. There’s no way that’s going to get me through the winter. But maybe it gives me some time to think about it.
Source: Amazon.
I use the composter shown above.
It has two weird features.
First, it’s made in Canada.
Second, it doesn’t work in cold weather. At all.
I guess that’s why they send them down here, eh?
Turns out , wintertime composting is a problem for anyone who composts small amounts of material, in a colder climate. The heat given off by decomposition isn’t enough to keep the compost warm. Composting grinds to a halt as temperatures fall.
My dad claimed that when he was a kid, dairy farmers in upstate New York would mound up cow manure around their barns for winter. This was not for the aesthetics of it. Instead, this was done to take advantage of the heat generated by large volumes of rotting manure.
In hindsight, that was a lot funnier the way my dad told it.
For two decades now, I’ve stopped composting kitchen scraps each fall, and resumed in the spring. Today it occurred to me … instead of just putting up with it, I should … maybe look for a solution?
What a radical thought.
Generically, the problem has two parts: Get rid of your kitchen scraps responsibly, and produce desirable compost for the garden.
Here’s the thing: I want the compost. In my experience, compost is nature’s Miracle-Gro(r). Or maybe vice-versa. It’s good for what ails a plant, and then some. It’s inexplicably helpful. Gardening black magic.
Otherwise, merely disposing of kitchen scraps responsibly is not an issue for me. I think. Elsewhere in the U.S., those scraps might be landfilled, at which point their anaerobic decomposition would generate methane. If vented to the atmosphere, that’s a bad thing. By contrast, Fairfax County VA incinerates its garbage, generates electricity from that, recovers metals as possible, then landfills the ashes. Here, food waste in the household garbage is just more biomass fuel for the electrical grid.
There’s some minor benefit in recovering the plant nutrients in those kitchen scraps. But not much. You only need trace amounts of those in the garden, and until the world runs out, those nutrients are cheap. At present, looks like 10-10-10 fertilizer (10% (by weight?) each of nitrogen, potassium, and phosphorus) runs about a dollar a pound, retail. I’m finally getting to the bottom of the 10-pound bag of that stuff that I bought fifteen years ago.
Should I fry in Hell for all eternity on account of that? I’m thinking, probably not, but it’s debatable. Conservation of mass says that N, P, and K went somewhere. If not stored in the soil in my yard, or gone down the sewer pipes, they’ve run off to the Chesapeake. But is that a large, medium, or small contribution of those nutrients, on a per-person-year basis? No clue.
If it were just a matter of getting rid of kitchen waste, without putting it in the household garbage, I have numerous free and paid disposal options in my area. Practically speaking, these would require me to store my kitchen scraps for a week at a time. But no longer than that.
Reportedly (my wife did the homework here): In Fairfax County, VA, I have at least these following locations for dropping off my kitchen compostables, for free. This includes animal products and plate waste, items you would not typically compost at home.
In addition, there’s the option of weekly composting home pickup for $360/year. Around here, one may subscribe to a privately-run once-a-week compost pickup service. Apparently the dominant local service is highly recommended by its users. It costs ~$30 a month for weekly composting service, and there is no mention of seasonal contracts, so I’m assuming it’s an annual contract. They’ll even throw in a couple of 20 pound bags of compost, per year, if you ask for it.
The free drop-offs lack appeal for a few reasons. One, for some reason, my wife isn’t keen on my routinely transporting buckets of decomposing garbage in her car. Two, I’d be on the hook for making that trip weekly, without fail. Three, these would require a dedicated car trip just for dumping the kitchen scraps, as I don’t routinely visit any of those places.
The energy required for my part of these options isn’t a big deal, but … It’s about an 18-mile round trip to the I-66 transfer station. That would use about the same amount of electricity as drying an extra load of laundry, a week, in the wintertime. (Call it 3.5 KWH/week.) Doing that for three wintertime months would generate around 40 pounds of additional C02 release. That 40 pounds is within rounding error on my household carbon footprint. Not a big deal.
I do wonder about, and am clueless about, the fossil fuels required for the paid pickup option. Near as I can tell, customers of that service are spread thin. The service provider has a distinctive bin, and I’ve only noticed one household in my broad neighborhood that puts a bin like that on the curb. That implies that there are a lot of truck-miles per pickup, but I have no clue just how many, or how large the carbon footprint of that is.
But mostly, where I live, the decisive factor is that putting kitchen scraps in the trash is more-or-less environmentally harmless. As noted above, they end up as biomass for electrical generation. They seem to have what economists term “free disposal”, environmentally. You can convert them back to carbon at virtually zero net cost. Spending any fossil fuels to get rid of those scraps seems like a losing proposition, from a carbon-footprint perspective. Let alone the time, effort (and potential car-stink residual) of any of the free dropoffs.
Why go to a lot of trouble, or some trouble and expense, just to shoot yourself in the foot, environmentally? Even if you’re only shooting yourself a little bit. If my options are to haul it myself, pay someone to haul it separately, or just put it in the household garbage, it makes more sense to chuck it in the garbage. At least in Fairfax County. YMMV.
Source: Ace Hardware. Not AI.
You find yourself buying shrink-wrapped shit. That is, packages of manure. Off the hardware store shelf. And not for cheap, either.
I think that was near the low point of my organic-gardening phase. In the distant past, I was a gardening purist and sought natural sources of nutrients for my garden. No Matter What.
Until one day, after transporting an entire 4’x8’x2′ utility trailer of horse bedding from the exurbs to my garden, I did the math and realized I could have bought the same amount of nitrogen for about $1*, in a nice, clean bag, at the hardware store. With far less expenditure of fossil fuels for transport. And far less effort.
* Calculated from data in this reference. Typical used straw bedding weighs in at maybe 4 lbs/cubic foot, and is one-fourth horse manure. Manure from a sedentary horse comes in around 7 pounds nitrogen per ton. My trailer would have held ((4x8x2 cubic fee, * 4 lbs/cu ft.)*(.25% manure * 7 lbs nitrogen per ton for manure / 2000 lbs per ton) = ) about a quarter-pound of nitrogen. Which is slightly less than you get in a pound of 30-0-0 lawn fertilizer. Which costs about a buck at Home Depot. You don’t believe me? Read the N-P-K percentages on the shrink-wrapped manure, above.
Organic sources of garden nutrients are nice because they are typically slow-release and low-nutrient-density. That makes it just about impossible to shock your plants with over-fertilization. (Or goof-proof, said as one who has goofed.) These also add carbon if worked into the soil, which improves its tilth. But the flip side of low nutrient density is inevitably a relatively high environmental cost in transportation energy. Finally, I would guess there’s less likelihood the nutrients will be transported by rain runoff, rather than being used by your plants.
Despite that, I decided that it was smarter to use artificial fertilizers sparingly than it was to lug around tons of low-nutrient-density organic matter. Hence the soil test kit comes out every spring. And I limit my organic materials to those I can gather at home. Including kitchen compost.
I’m all for organic sources of garden nutrients. I just don’t want to haul them any significant distance. Let alone dispose of the packaging.
Before I go to any significant cost to fix this problem, I need to have a quantitative handle on the benefit. Just how much kitchen-waste compost do I typically produce, in the (roughly) nine months a year that the composter actually works. And by inference, how much will I gain from an additional three months.
On the output side of the equation, I’d guess that my composter produces about a cubic foot of finished kitchen-scraps compost every three months. I seem to empty one side of the composter about that often, and each emptying yields one and a half five-gallon buckets of compost. (N.B. a cubic foot is about 7.5 gallons). Working it in the other direction, that’s about a third of my estimated initial volume of kitchen waste, which seems about right. (I mix “brown” material 50/50 with the kitchen waste, so in theory, in three months, six cubic feet of total composter input ends up generating one cubic fit of finished compost, or just under an 85%) reduction in volume. Not sure if that’s a reasonable figure or not.)
So that’s the question. Where I live, there’s no particular environmental harm in chucking food scraps in the garbage. The only real benefit of not doing that is the highly desirable compost. So as I work through this problem, the issue boils down to how much effort should I go to, to obtain an extra cubic foot of high-quality kitchen-scrap compost, per year?
I recall this coming out as a new product just a few years ago. Now there’s an entire industry segment for countertop electric composters. These dry and grind your kitchen scraps, resulting in “shelf-stable” dehydrated material.
Looks like your typical countertop electric composter will:
That last one is my estimate. The manufacturers say somewhere around that much electricity per batch. But they must be counting on the machine to be only about a third full when run, typically. (Calculation not shown. It was boring.)
From the gardening perspective, the end product seems a bit weird to me, in that, well, it’s still food. It’s not composted, as in rotted. It’s dehydrated, ground food scraps.
Really, the only difference between this and a food dehydrator is that this dries your food (scraps) and grinds them up.
It’s as if someone mated a hair dryer and a garbage disposal. I can’t help but think that the (stressed) moving parts predict a relatively short lifespan.
If I had to work up a figure for my expected electrical use over the winter, for this device, I’d guess that I’d run this for three months (90 days), producing about two quarts of kitchen scraps per day. If that then takes 1.5KWH per load, over the course of the winter season this would use 135 KWH. In Virginia, that would result in about 90 pounds of additional C02 emissions per season, from the electrical generation. (I can’t count on any reduction in landfill methane from not putting my scraps in the trash, because Fairfax County incinerates everything. I think.)
Aside from the cost, the smell when operating, the potential for the results to attract vermin when used outside, the electricity consumed, and the likely short lifespan of the device, this seems like a pretty good option.
One common nugget of internet wisdom is to freeze and store your winter garbage, and compost it later.
Another alternative is indoor worm composting.
Nope.
First, all the internet gives me, for fixing my current composter, is lame advice. Ooh, just move the composter to a sunnier spot. That should help with daytime warmth. Aah, what you need is some insulation, so the heat of decomposition isn’t lost.
Qualitatively, those make sense. Yeah, you got it, I want my compost to be warmer.
Quantitatively, there’s not a chance either one will do the trick. As a solar heater, my composter sucks. That’s not what it was designed for. It has a lot of mass, but little sun-absorbing surface area. It doesn’t trap any hot air (it’s not glazed), it’s just black plastic sitting in the sun. And did I mention it’s plastic, yet it relies on conduction of heat through the durable plastic walls into the composting material. Separately, as a heat-retaining compost holder, it sucks. For one thing, the container of compost is suspended, allowing cold air to contact the container from all sides and both ends, all the time. And you literally can’t insulate the ends or the thing won’t spin.
Let me now discount some out-of-the-blue solution to this. For example, it might be possible to purchase bacteria that operate efficiently at lower temperatures. I’ve seen hints that such exist, but I haven’t really hit upon a product aimed at the home market. Or, surely I could use electricity to warm the composter, but (see “free disposal” above) that surely increases my carbon footprint. Let me ignore things of that nature. One’s over my head, the other seems like outright stupidity.
And yet, the internet is kind-of right, because, practically speaking, it comes down to finding a cheap way to keep that composter warm. Cheap, because my total reward from this is to reap a whole extra cubic foot of compost per year.
And so, first shot, I covered my composter, as I might cover a plant. In effect, I mocked up a little greenhouse for it, where it stood. Just like my tomatoes.
Maybe the bricks behind it provide thermal mass. Maybe that’s where the composter sat and I didn’t want to try moving it when full.
Having looked at solar air heaters, I now know to classify this as a direct solar heater, and as such, probably low-powered. So I don’t think this, by itself, will do it. It’s still a lot of mass, and not a lot of surface. (Plus, if it does, I’m going to kick myself for not having done this sooner.)
But, in my back pocket, I have the notion that it’s not hard to add an indirect solar air heater to that. And once you go that route, you can, to a limited degree, pick your power to match your application. So the obvious next step, if and when this fails, is to take the one I just built, mod as required, and see what temperature it can produce inside that composter “tent”.
But that’s as far as I go, today. Maybe this will do the trick for the next few weeks. As with my tomatoes, it’s a season-extender. I doubt this is going to get me through the winter.
Answer: Because they’re small. That’s it. It’s just basic physics. And there’s nothing that can be done about it.
In Post #1843, I figured out and explained why ceiling fans are vastly more efficient that box fans. Where efficiency is measured by cubic feet of air moved per minute, per watt of power used (CFM/watt).
The answer turned out to be remarkably simple: To move the same volume of air, a smaller fan blade has to move that air much faster. That’s just arithmetic. (If the area swept by a 20″ box fan blade is one-seventh the area swept by a big ceiling fan, the box fan has to move the air seven times faster, to keep up with the volume moved by the ceiling fan.)
Moving air faster takes much more energy than moving it slowly. Not due to the energy-wasting turbulence that might create ( though that can be a factor), but merely because it takes more pressure to move air faster, and overcoming that pressure takes more energy.
Roughly speaking, CFM/watt should scale inversely with the size of the fan. Given identical designs and motors, a box fan that is one-seventh the size of a ceiling fan should take seven times the wattage to move the same amount of air. Roughly.
That’s all laid out in Post #1843.
Today the penny dropped, and I realized that this same phenomenon explains the poor performance of bathroom vent fans. Seems like bath fans take forever to clear a bathroom. And I include all bath fans, almost regardless of make or quality. Where a box fan stuck in a window could clear the air in a bathroom in a couple of minutes, an in-ceiling bath fan might take half an hour.
At best, a bathroom vent fan might have 6″ blades, feeding a 6″ diameter duct. (Although 4″ duct for bath fans is far more common). Since the area of a circle goes as the square of the radius, the area swept by the blades of a 6″ bath fan would be about ( 3-squared / 10-squared = ) 9% of the area swept by the blades of a 20″ box fan. And so, to move the same volume of air as a box fan, a hypothetical 6″ bath fan would require (1 / .09 =) 11 times the wattage.
Let me now put that to the test, via virtual shopping at Home Depot.
And, sure enough, the median bath fan from Home Depot moves about one-tenth as much air per watt, compared to a box fan.
Bottom line: A bath fan that could clear a bathroom as fast as a box fan would draw ten times the wattage of the box fan. If you could squeeze that much air, that fast, through the ducts, you’d need to have a 500-watt bath fan*, in order to clear a bathroom as fast as a box fan sitting in the window. That, before we even consider whether or not you could move that much air through a small duct without undue losses due to turbulence. That, before we consider how much noise that would make.
* That’s 2/3rds of a horsepower, more or less. A big electric motor, in this application.
And so, the apparent poor performance of bathroom fans is not a figment of my imagination. Bath fans move air quite slowly, compared to (e.g.) common box fans. It’s not a design flaw, or an intentional choice. It’s just physics. The smaller the fan, the more power it takes to move a given amount of air. And bath fans — typically restricted to 4″ ducts — can only move a tenth of the amount of air that box fans can move, per watt of power.
In a nutshell: In an afternoon, I made a roll-up solar air heater using plastic sheeting, a pile of green mesh vegetable sacks, some tape, and a fan. At solar 3PM, that’s now putting out a nice stream of air at just under 130F. That should be adequate to serve as the hot air source for drying food.
See the just-prior post for the theory. In particular, why a mesh-filled tube is a pretty good choice for a solar collector.
When I’m done with it, I can just roll the whole thing up and store it in a nice, compact package.
I want to make a solar air heater, to use for drying my garden produce. Mainly, for making dried tomatoes. Solar-powered, because otherwise, in the humid climate of Virginia, my only reliable option is to use an ungodly amount of electricity to make those dried tomatoes..
Source: Post G22-010.
At this point, I’ve exhausted all of the simplest solar-drying options.
Even in Virginia, if you get perfect drying weather for four days in a row, you can dry tomatoes using old-fashioned open-air drying (Post G23-056). The problem is, you can rarely count on a stretch of weather like that, around here, when you need it.
I also tried making a simple power-ventilated direct solar food dryer. (That is, a clear-topped, ventilated box in which sunlight shines directly onto the food to be dried.) My conclusion is that direct solar dryers just don’t have enough power to dry tomatoes reliably in my humid climate (Post G23-058, Post G23-057).
My aha! moment came when I realized that direct solar food dryers are simple flat-plate solar air heaters. The food sits on or above that flat plate. Simple flat-plate solar collectors are the least efficient way to convert sunlight into heat energy.
So here I am. My late-season tomatoes are (finally!) ripening, so it’s time to get this done. I’m upping my game by making an indirect solar food dryer. This is a dedicated solar air heater, hooked up to a box that contains the food to be dried. That arrangement allows you to increase the power input, both by increasing the efficiency of the solar energy capture, and increasing the ratio of solar energy capture area to area of food to be dried.
Source: Government of New Zealand.
Funny thing about the word “cheap”. Once upon a time, it had no negative connotations. It was used as we might use “inexpensive” today. Goods were advertised for their exceptional cheapness. Which, back in (say) Colonial American times, meant low price, not shoddy construction.
My point being that as long as I’m making a cheap and flimsy solar air heater, I might as well celebrate that. No sense in trying to make a high-quality cheap and flimsy device. Might as well make it as cheap and flimsy as possible.
In pictures:
Plastic, about 8′ wide by about 20′ long.
Plastic sheet folded in half to make a long 4′ wide tube, then taped (see tape seam at left), with a 4′ wide piece of radiant barrier inside the tube to serve as the bottom. I’m not even sure that radiant barrier (or equivalent piece of black plastic) is necessary. FWIW I used Gorilla (r) duct tape, and that seems to be sticking well to the plastic sheet.
A bunch of mesh vegetable sacks drying in the sun, after being hosed off. Why do I own these? Long story. But because I already owned them, I’m using this as my solar collector material, rather than black screening.
The plastic tube, now stuffed with those mesh sacks, balled up. Try to pack it loosely, but with no voids that would let air flow around the mesh, rather than through the mesh. You want to force the air to flow through the mesh so that it will pick up heat from the sun-exposed mesh.
Ready to run. Fan is clipped into the near end, a piece of flex duct is clipped into the far end, and chunks of wood weigh down the top. You can see that the top still balloons up a bit, between the pieces of wood, from the force of the fan.
The fan is an ancient twin-bladed window fan. I’m guessing that with no resistance, it moves 250 CFM on low, and draws maybe 30 watts. With the resistance imposed by passing through the mesh, I have no idea how many CFM it moves.
Same, side view.
Same, end view.
A nice stream of 129F air, at solar 3 PM, on an 80F day, with no adjustments? That’ll do.
Total assembly time was around two hours. And I now have a roll-up solar air heater that is adequate for the task of drying tomatoes.
I am greatly simplifying my task by using Nesco food dryer trays. With the addition of a bit of tape, these can be stacked to form an air-tight cylinder, with the food to be dried neatly laid out within that cylinder. All I need to do is place that cylinder above an appropriately-sized hole in a cardboard box. Run the flexible duct from the solar air heater into that box, and that will serve as the food dryer unit.
Note that with this design, the cardboard box itself doesn’t get wet. All the humid air from the food goes up the stack of trays, and out.
Materials/tools list for the solar collector:
Materials for the food dryer unit
I’d like this to to produce around 900 watts of heat, on average, over an eight-hour sunny summer day, at 40 degrees north latitude. Assuming this is 30% efficient at capturing sunlight, then, based on my prior calculations, this should capture an average of 18 watts per square foot. So I’m shooting for about 50 square feet of collector.
I have no intuition as to the right shape. I’m guessing that depends on a lot of factors. The material I’m starting from is almost 20′ wide, so I’m tentatively planning on a tube about 4′ wide and 20′ long. That’s a bit larger than necessary, but it matches what I have on hand. Of that 20′, a couple of feet on either end will be used to connect to fan and duct, and so will not contribute much, if anything, to solar energy collection.
I’m guessing that one 8′ x 16′ piece of clear plastic sheet should be adequate to form the tube. I’ll need a further 4′ x 16′ piece of black or reflective plastic to line the bottom of the tube. And, optionally, one more piece of clear plastic, 4′ x 16′, to add to the top for “double glazing” of the finished, quilted tube.
In my case, that’s a box of mesh produce sacks that I’ve had on hand for years. (These were part of a failed attempt to simplify the handling of my firewood.)
Plastic window screening should work fine, but is an expensive solution if you are using new materials, due to the amount of material required.
Or, you might try doing this with no filler. Just blow air down a hollow clear-topped tube. That should make this much less efficient at capturing sunlight. So make the tube bigger than you would otherwise.
Beyond that, if you use something that isn’t compressible, you lose the ability to roll this up when you are done with it. If you don’t value that, you could consider:
This couldn’t be easier. Get some clear plastic sheeting, e.g., the stuff they sell as dropcloths at the hardware store. (In my case, I’m using greenhouse plastic, which is more UV-resistant than garden-variety hardware-store plastic sheeting.clear-topped plastic tube.) Fold it in half, and tape the edges together.
I’m going for a reflective bottom because I own a roll of house-construction radiant barrier material. The idea is that any light penetrating the layer of loose fill will get reflected back up into that loose fill. And, where the fill is at least a half-inch away from the radiant barrier, the barrier will act as insulation against radiation heat loss through the back of the tube.
For me, this was as simple as temporarily closing off one end of the tube, scrunching up the mesh sacks, chucking them inside, and using a stick to arrange them into a single, packed mass.
This isn’t precision work. The air is going to flow through all 16′ of the tube. As long as there’s no continuous channel through which the air can flow from end to end and bypass your porous material, you should be fine.
You want air to pass through the porous filling, not above it. So you want to keep the plastic top sheet right down on top of the filling, in some fashion.
I was originally going to “sew” or tape the top and bottom together in places, to do this. But on reflection, the easiest thing to do is weight the top down, while obstructing as little light as possible.
I’m just going to toss some 2×4’s onto the top of the sheet, and, if necessary, weigh them down with (e.g.) bricks.
Optionally, add a second layer of “glazing” by tossing another clear plastic sheet on top of this. That will trap insulating air where the top of the tube is depressed by the quilting or the 2x4s. I’m guessing this isn’t worth it, but I make try adding it and taking it off to see what happens to the resulting air temperature.
Attach a window fan or 20″ box fan to one end, and a short length of flexible dryer vent to the other.
I want to be able to take this apart at the end of the season, to store it, so I’m doing these attachments with lengths of bungee cord. You could just as easily make the attachments with tape, and peel back the tape at the end of the season.
Because I’m using round Nesco trays, my air distributor will just be a box, somewhat larger than the trays, with holes for the dryer duct and the trays. Run the dryer duct into the box. Place a piece of cardboard on top of the uppermost tray, to make sure the hot air hits all the food as evenly as possible. That’s it.
Place the tube on the ground, in the sun. Place weighs on top of the flat solar-collector tube, to keep the top from ballooning up. Attach duct, fan, and (eventually) food drying box. Turn on the fan.
It works. And it’ll roll up at the end of the season. So that’s a success.
This could use a bit of tweaking.
I probably used way more mesh “stuffing” than I really needed. I can’t even see the reflective bottom of the solar air heater, through the green mesh bags stuffed inside.
I’m sure this would get hotter if I could tilt it so that it was perpendicular to the sun’s rays. As one would do with a solar panel.
But … it works well enough as-is. So I don’t see any need to modify it. I can unroll it in the sun, attach small fan and duct, and produce a nice stream of hot air as long as the sun shines. That’s really all I need it to do.
Arguably the most mickey-mouse aspect of this right now is the weights for the top. Without those, the plastic sheeting simply balloons up, and the air passes over the mesh, not through the mesh. Tossing some sticks on top makes it work, for now, but I’d like to get a more elegant solution at some point.
I’m now going to roll this up and put it away until my final crop of late-season tomatoes starts ripening in earnest. Then I’m going to use this for a last batch or two of dried tomatoes. Weather permitting.
Turn the fan around and stick it in the other end of the tube.
After I put this together, I went looking for a better fan. Window fans of the sort I’m using really shouldn’t be used to push against considerable resistance.
That’s when I realized that if I sucked air out of the tube, instead of blowing air into the tube, the entire problem of having the surface of the tube balloon up simply goes away. All the wood and metal pieces on top of the solar air heater are unnecessary. And I end up with a simpler and more elegant design. If such a word can be applied to this cheap and flimsy roll-up solar air heater..
Sometimes you need a deadline to get motivated.
I want this done no later than close-of-business (COB) tomorrow.
No particular reason for COB, it’s just helpful to have a deadline. Continue reading Post 1857: Building an indirect solar food dryer. Part 1.
No less an authority than the USDA is now on the bandwagon for #leavetheleaves. That is, the idea that gathering and disposing of fallen autumn leaves is foolish from an environmental standpoint.
The conspiracy-minded among you may view this as just another facet of the Deep State, an evil cabal within the U.S. Civil Service determined to disrupt every facet of the American Way. Yes, stooping so low as to attack that most harmless of small-town fall rituals …
… requesting that citizens rake/blow leaves to the curb, so the Town can repeatedly drive its high-decibel fleet of dedicated leaf-vacuuming equipment through town, and so spend hundreds of thousands of dollars to suck up those leaves, then trucking hundreds of tons of leaves down the interstate so that they can be sterilized via hot composting at some remote location, ensuring that no offspring of this year’s crop of butterflies and similar insects survive.
Well, at least, that’s the tradition in my small town. It’s an industrial-scale process that’s a far cry from Normal Rockwell, if you get my drift.
Source: Pinterest.
The USDA is just the most recent in a long line of organizations that have gotten behind the idea that leaf collection and disposal of this type is a relic of the past. Historically, in this area, it’s the immediate successor to the era in which suburbanites routinely raked up and burned fall leaves. Before that was banned owing to the resulting air pollution.
Locally, even the surrounding county (Fairfax County, VA) has proposed to stop doing vacuum leaf collection (see Post #1821). In part, because that turned out to be a real hassle for county staff this past year. But also for all the good reasons outlined on the USDA web page.
But in Vienna, VA, traditions die hard, unless there’s some profit to be made in killing them. And new learning percolates excruciatingly slowly. Town-wide, this is mostly about doing our bit to slow the insect apocalypse (reference National Academies of Science). Not sure that matters to most residents, even though it should, from a survival-of-our-species standpoint. All said and done, it’s still an open question as to whether we can break ourselves of this 40-year-old tradition. Just to benefit a bunch of butterflies and such.
My prior screeds on this subject include:
This, in addition to several posts on the economics of the Town of Vienna’s centralized leaf collection and disposal process.
Pictures in this post are mainly from Gencraft.com and Freepik AI
