Category: Garden

Posts about gardening and related topics, such as canning and maybe other aspects of food preservation.

Post #1921: Psychrophilic bacteria for winter composting, setting up the experiment.

 

You might reasonably think that a post featuring my rotting kitchen scraps is a new low for this blog …

… though I’d bet there are some in the Town of Vienna who might disagree.  But that’s water over the dam.

In any case, you’d be wrong, because today I treated half that pile of rotting kitchen scraps with cold-water pond … eh … stuff.  That converts this pile of rotting (or, more precisely, non-rotting) garbage from a mere oddball gardening obsession into an exciting citizen-scientist experiment.

Anyway, as promised in Post #1917, I leveled up the two compartments in my tumbling composter and added cold-water pond treatment to one side.  This stuff:

The idea being that a big dose of psychrophilic (cold-loving) bacteria might jump-start my kitchen-scrap composting.

Composting activity has pretty much ground to a halt, due to the cold outdoor temperatures, despite my having built a little insulated solar shed for the tumbling composter.

Methods:  After leveling up the two sides of the composter, I added about a third of the bottle to one side of the composter,  in several small doses, tumbling the compost vigorously with each dose.  And added a packet of something advertised as enzymes to break down cellulose (though that seems more than a bit far-fetched to me, for reasons I won’t go into).  I’ll tumble it daily, maybe add another treatment in two weeks or so.

In a month, I’ll check to see whether or not the level of compost in the left (treatment) side has dropped materially below the level in the right (control) side.

This is my last-ditch effort to get my tumbling composter to continue working through the winter.  This pond treatment cost $30, so I figure I ought to try to get my money’s worth.  If the stuff doesn’t work for this use, at least I can affirmatively document that it doesn’t.  Hence running this as a controlled experiment, instead of just dousing the whole batch of compost at once.

I’ll be surprised if it works.  But that’s what experiments are for.

Results in a month.

Post #1900: The USDA released a new map of U.S. plant hardiness zones this week …

 

Source:  Maps are from USDA.  I added the line marking the boundary between hardiness zones 5 and 6.

… and nobody cared.

Which is a good thing.  I think.  On balance.

On the one hand, it’s good that they released it.  That’s my take on it, knowing the controversial history of the USDA hardiness zone map.

On the face of it, the red lines on the map above simply mark a data-defined boundary. Below that line is the area where winter temperatures should be expected to stay above -10F.  That’s based on the 30 years of local weather data, prior to the map date.  As the U.S. winter nighttime temperatures have warmed, those lines are moving north about 5 miles per year, in Missouri.  And, as I understand it, at roughly that rate, averaged across the entire U.S.

Back to the here-and-now, if you look at the illustration above and immediately say, hey, what happened to the circa-2002 map?  Why did they skip a decade?  Then you get an interesting story.

The answer is, Republican administration.  The Bush Jr. administration just somehow couldn’t quite seem to get around to allowing the public to see the updated version of that map.  The widely-held presumption is that they withheld the information precisely because it showed what I’ve highlighted above:  the USDA hardiness zones are migrating north.  That’s easily-grasped evidence of the early impact of global warming on the U.S.  And so that information was suppressed.

(This, despite the nonsensical CYA language that the USDA insists on including in the footnotes to the description of the map methodology.  They seem to say that “climate change” requires 50 years of data, and since each individual map only covers 30 years, you can’t infer that this is the impact of climate change.  Despite the fact that the underlying span of data across the full set of maps is now more than 50 years.)

On the other hand, I think those changes ought to get more press coverage.  This isn’t natural variation.  This is a clear and understandable signal of global warming’s initial effects.   And as slow as these changes are, relative to a human lifetime, there’s nothing on the horizon to suggest that they are going to stop any time soon.  Five miles a year doesn’t sound like much, until you realize that the U.S. is only 1000 miles north to south, and that things will move a lot faster once global warming really gets rolling.  And that it’s fairly hard to grow corn and wheat in a sagebrush and cactus desert.

So, even though I’m still in Zone 7, I think this deserves more press than it has gotten.  And I think that the Bush-administration suppression of the circa-2002 map needs to be remembered, right alongside the temperature data.

What are we talking about?

Source:  USDA.  I removed some details from the map (e.g., degrees C scale) to make it clearer.  Thus, I must say that: a)  the map is not the official USDA Plant Hardiness Zone Map, and (b) the USDA-ARS and OSU logos are eliminated.  If you want to see the full official map, follow the link.

The map above shows the coldest wintertime temperatures in each year, averaged across 30 years of data.  The 2023 map literally uses weather data from 1991 to 2020.

The map provides guidance as to what perennial plants can usually be expected to survive the winter, unprotected, in each location. 

That’s guidance, not certainty.  As the owner of a lime tree, I am acutely aware that citrus trees will typically die back to the ground if they go below about 28F.  Plausibly, you need to live somewhere near Zone 10 or higher (e.g., Florida) before you can expect your citrus trees to survive reliably, out-of-doors, unprotected.  Even so, the occasional freeze will hit Florida, so significant frost damage to Florida citrus groves seems to occur every few decades or so (reference).

More generally, if you ever buy a perennial plant from an on-line nursery, they’ll let you know the hardiness zones in which the plant is expected to survive.  Or they’ll give you information such as “hardy down to 0F”, and leave it up to you to know what USDA hardiness zone you live in.

It’s not hard to get your hands on the underlying data from which these maps were created, for example, via NOAA.  I’ve plotted the annual wintertime lows before, for the weather station at Dulles Airport.  Here’s 60 years of wintertime lows, as recorded at Dulles.

The obvious upward trend that you see above is pretty much the norm for most of the U.S.  So it’s no surprise that the revised USDA map shows those plant hardiness zones creeping northward.

In fact, my location (Vienna VA) graduated from Zone 7A (expected annual low of 0F to 5F) to Zone 7B (5F to 10F).  I was firmly in the middle of 7A, now I’m barely at the edge of 7B.  That’s reasonably consistent with the increase in wintertime minimums shown in the Dulles data above.

Footnote:  Hardiness zone creep exaggerates average warming

One final footnote is that, due to the nature of C02-driven global warming, the northward creep of the hardiness zones exaggerates average warming.

The reason for this is simple:  The largest impact of global warming is on nighttime temperatures.  (E.g., via Scientific American).  And on winter temperatures (E.g., via Axios).  By inference, the biggest impact of all should be on nighttime winter temperatures.  And, typically, the annual low temperature in an area is set during the course of some winter night.

If nothing else, knowing this is a quick way to dismiss denialist arguments that, somehow, the observed warming on earth is due to changes in the sun.  (That, despite direct satellite measurement of solar irradiance, dating back to the 1970s, showing no such thing.)  The fact is, the warming is more pronounced at night, and in the winter, both times of limited sunshine.  Heuristically, if enhanced atmospheric C02 is a blanket, that blanket matters more when it’s cold and dark.

Conclusion

The real lesson here isn’t the map, per se.  Anyone who cared to analyze the publicly-available weather data — as I did above — would already have a strong expectation that the official USDA climate zones would continue to move northward, in this most recent update of the USDA map.

Really, the big lesson here is the missing circa 2002 map.  There was a time when Republicans so thoroughly insisted in keeping their heads in the sand, on global warming, that they found excuses not to update this map.

Has that changed?  Are Republicans on board now, with the idea that global warming is real?   I doubt it, but there’s no way to know.  The last two iterations are both dated to periods with Democrats in control of the administrative branch of government.  So, as to whether or not a Republican administration would allow this to be updated on a once-a-decade schedule, I guess we just won’t know until we see it.  Or not.

Post #1891: If the on-line deal seems too good to be true, what do you do?

 

At what point is an on-line deal so good that you decide not to buy it?

And if so, why?

In the modern U.S.A., with markets dominated by cheap Chinese goods, is there still any such thing as a price that’s too low to be believable?

I have to write this one fast, as this amazing deal I’m looking at won’t last long.  I must order now, or I might miss out on the deal of a lifetime.  Continue reading Post #1891: If the on-line deal seems too good to be true, what do you do?

Post G23-067: Garlic and soil sulfur.

 

I’m going to plant some garlic soon.

For that, I figured I’d add sulfur to my garden soil.  Everybody says that’s a good idea.  And if it says it on the Internet, it has to be true, right?

Yeah, well, there’s a little more nuance to the story.  Near as I can tell:

  1. Sulfur only helps if your soil is truly sulfur-deficient.   I.e., you can’t create “super-garlic” by loading your soil with sulfur.
  2. As a home gardener, you have no good way to tell whether or not your soil is sulfur-deficient.
  3. So a modest addition of sulfur to your garlic bed is a form of cheap (and mostly harmless) insurance against growing “bland garlic”.

With soil sulfur, as long as you meet the minimums that garlic requires, any excess is wasted.  You just have no easy way to know what that minimum is.

Soil sulfur and garlic flavor, an interpretation of the scholarly literature.

Above:  The heartbreak of bland garlic.

Garlic is about 0.5% by weight sulfur (reference).  Give or take.  Allicin is the main chemical that gives garlic pungency when cut or crushed (reference).   About 40% of the weight of the allicin in garlic is sulfur (calculated from this reference).  So, for sure, you need sulfur to make garlic pungent.

Gardening folklore says that garlic grown in sulfur-deficient soil will be bland.  Presumably that’s due to reduced alliin/allicin content.  Given the chemical composition of allicin, that makes some sense.

While this is frequently repeated on the internet, it’s hard to demonstrate empirically.  Research results appear mixed.  Some research shows that garlic allicin content rises strongly with application of sulfur.  Some research shows no effect at all.

A plausible explanation offered for these mixed results is that most soil already has adequate sulfur for garlic cultivation, and that additions beyond the level have no effect.  Interestingly, the sole study of hydroponically-grown garlic showed a strong positive relationship between sulfur provided to the plant, and allicin content of the finished garlic (contrast Table 1 and Figure 3 of this reference).  If I’ve interpreted those findings correctly, then you can’t produce super-garlic by loading your soil with sulfur.  But you can produce bland garlic if your soil is truly sulfur deficient.

In this case, then, there’s probably some truth to this bit of gardening folklore.  Sulfur soil amendments don’t appear to be a path to growing extra-garlicy garlic.    Instead, sulfur soil amendments are more like insurance against a poor crop of garlic.

Fun factoids about garlic and sulfur

Weird fact #1:  Once upon a time, rain provided all the sulfur you needed.   Eastern U.S. farmers didn’t used to have to worry about having adequate soil sulfur.  Acid rain saw to that.  Go back a few decades, and rain falling through the ambient air pollution — including sulfur dioxide — deposited more than adequate sulfur annually.

Weird fact #2:  Rainfall now removes sulfur from the soil.  Plants can absorb sulfur once it forms sulfate, that is, a mineral salt containing sulfur.  These sulfates are typically so water-soluble that they wash out of well-watered soils.  And now that we’ve cleaned up most of our acid rain problem, rain water leaches sulfur out of the soil, instead of providing it to the soil.

This same phenomenon leads to:

Weird fact #3:  Hilltops tend to have sulfur-deficient soil.  It gets leached out as rain runs through and out of the hilltop soil.  More generally, sulfur levels can vary considerably within a given farm plot, both horizontally (from area to area) and vertically (within the soil profile).  All those phenomena are driven by the high water-solubility of sulfates, and so, by the typical flow of water in a field.  The upshot of that is that a home gardener, taking a soil sample, and getting a reading on sulfur, may not know much about the level of sulfur in the garden as a whole.

Weird fact #4:  Plants can’t use pure sulfur, but you can buy and apply pure sulfur to your soil.  Plants can only absorb the sulfur after it’s converted to sulfate, that is, a metallic salt of sulfur.  That conversion is done mostly by the action of soil bacteria.  In effect, elemental sulfur is slow-release sulfur, with the rate of release being controlled by the rate of bacterial action, which depends on size of the sulfur particles, soil temperature, moisture, and acidity.

Weird fact #5:  There’s no easy test for it in your soil.  I looked up the for-real tests for sulfur levels in the soil, and it took me right back to college chemistry classes.  Use of carefully measured reagents, long periods of agitation, followed by careful (drop-by-drop) titration to get a quantitative estimate, and so on.

Few soil tests available to the home gardener measure sulfur.  On Amazon, I found just two options, and both involved mailing a soil sample to a laboratory.For example, this test kit, $30 on Amazon, will show you the nutrient levels — including the sulfur level — in one soil sample.  As will this $100 soil test kit.  Both are mail-in kits, with the testing provided by some centralized lab.

Here, in Fairfax County, the soil tests provided via Virginia Tech’s extension service do not measure sulfur (per this listing on the Fairfax County website).  I don’t know whether that’s because sulfur isn’t an issue in the heavy clay soils of Virginia, or whether it just rarely matters to the home gardener.

In fact, there’s an argument that there’s no one, universal good test for the bio-availability of sulfur in the soil.  (That’s my take on this discussion.)  It seems plausible that even if you “test your soil for sulfur”, the results will be a poor guide to the amount of sulfur available to plants grown in that soil.

The upshot is that you, as a home gardener, can throw 30 bucks at it, and get a number back, for the amount of sulfur in your soil.  Whether or not that number actually tells you anything useful is debatable.

Weird fact #6:  Mostly harmless?.  Apparently you need little enough of it, for most plants, that it’s often applied pro-actively, without testing, in commercial farming.  And it doesn’t lead to (e.g.) algae blooms when it runs off with the storm water, the way nitrogen and phosphorus do.

Weird fact #7:  If you add organic matter to your soil on a routine basis (e.g., compost, mulch, etc.), you probably have adequate sulfur for most of the plants you would care to grow.  That seemed to be almost regardless of the exact organic matter that you are adding.  In any case, that’s the way I interpret the gist of what I’ve been reading.

Bonus fact:  The allicin in freshly-cut garlic has such strong antibiotic properties that it earned the nickname “Russian penicillin”, for its use in expedient wound dressings, by the Russian army, in WWII.

My upshot:  Gardening via Swedish death cleaning.

When I run all that through the blender, my take on it is that the home gardener is mostly flying blind on this one.  You can pay for a one-shot, mail in soil test that will show you the sulfur level in one soil sample.  It’s not clear that’s going to tell you what you really need to know about the sulfur in your garden, generally.

Instead, you might add some sulfur to your soil, when growing garlic, just in case.  Just in case your soil is so deficient in sulfur that it will reduce the quality of the resulting garlic.

As far as I can tell, it’s pretty hard to over-sulfur you soil, at the levels we’re talking about.  For my 8’x4′ bed of garlic, a bumper crop of garlic would take up about 32 grams of sulfur.  Replacing that, at 2 grams per cubic centimeter, would require just about one tablespoon of pure powdered sulfur. 

My bottom line is that I’m going to rely on Espoma Holly-Tone as the sulfur source for my garlic.  (See prior post).  That decision is based on the time-tested gardening rule of  “I already own a big bag of it.”  I can’t buy less than a one-pound bag of elemental sulfur.  At the rate I would use it, that’s way more than a lifetime supply of it.  I’d end up with yet another bag of gardening stuff, sitting on the shelf.  As I am currently in a round of Swedish death cleaning, that’s not the direction I want to take.

So Espoma Holly-Tone it is.

Ancient folklore instructs me to pour an uninterrupted circle of Holly-Tone around the perimeter of the garden bed, moving widdershins.  This both ensures a good crop and keeps vampires out.  It’s 5% sulfur, and, best guess, a scant three cups (1.5 pound) of it, on a 4’x8′ bed, should provide the 32 grams of sulfur I might plausibly need for complete garlic and vampire insurance.

Photos are from Gencraft.com and Freepik.com AIs.

Post G23-066: A little fertilizer calculation, or why I #leavetheleaves.

 

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.

 

A time to plant garlic, and a time to refrain from planting garlic.

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”.)

Two options for Nitrogen fertilizer

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:

  1. An impractically large layer (e.g. feet of depth).
  2. An inconveniently large layer (e.g., one foot of depth).
  3. A few inches of leaves.

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.

Like sulfur for garlic?

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.

Can I do this with Espoma Holly-Tone?  Maybe.

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.

Conclusion.

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.

Post #1863: Overthinking winter composting.

 

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.

Background

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.

What’s that garbage worth to you?

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.

Plenty of ways to get rid of household kitchen waste

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.

  • The Fairfax County I-66 and I-95 transfer stations/landfills (documented, here).
  • plus all ten farmers’ markets run by Fairfax County (same document).
  • Selected Mom’s Organic Markets (Moms) (documented, here)
  • Whole Foods in Vienna (solely an internet rumor, not documented).

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.

You know you’re a suburban gardener when …

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.

A tempest in a compost tea pot?

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?

Stuff I’m not going to do.

Countertop electric composter. 

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:

  • cost about $350.
  • hold maybe three quarts of kitchen scraps maximum
  • dry and grind that in 6-10 hours
  • produce a dry, shelf-stable product.
  • reduce the volume by about 90%.
  • produce odors as they work.
  • Use about 0.8 KWH per quart of scraps.

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.

Ew.  Just ew.

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.

Groping toward a solution

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.