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Rabu, 15 Juni 2016

Economics of Growing Greens by Artificial Light

We had a thought the other day about growing greens like lettuce, spinach, swiss chard, and kale inside during the winter months.  What would it cost us to do that, in the limiting case that the greens would get no natural light through our windows?  (Thats actually not too far from the truth--most of our windows face north or are shaded for all but a few hours a day.)

We went back to take a look at our aquaponics setup, which makes use of four 4-foot-long T8 fluorescent light bulbs, and which we used to grow some swiss chard, thyme, basil and dandelion greens at our old place (there were other plants, too, but those were the four that grew fast enough to give appreciable yields).  We were pretty satisfied with the amount of greens we were able to produce from that little 48" x 24" area, but we never actually crunched the numbers on the economics.  So, today we decided to do a quick calculation to see how much it was costing us to grow all those greens, at least as a ballpark figure.

A picture of the working aquaponics grow bed at a young age.  Later it would look much bushier.

The lighting system uses four 32-Watt bulbs, and our electricity rate is about $0.13/kWh. That is, it costs us thirteen cents to consume 1,000 Watts for one hour.  Watts are actually a rate of energy consumption--Joules per second--but total energy consumed is what gets billed.  So instead of doing the logical thing and using Joules as a standard unit, utility companies use the convoluted unit of kilowatt-hours.  Add that to the list of science-business conventions that dont make sense.  But at least its based on the metric system!

So, when the four bulbs are all lit up, were consuming 128 Watts (or 0.128 kilowatts).  If we run the lights for 10 hours a day, we consume 1.28 kWh of energy, which costs us $0.17. (Differences in rates for peak hours, sales tax, and all the other junk the utility company charges for are included in that number.)  Seventeen cents per day doesnt sound too bad.

In the aquaponic system pictured above, we had four swiss chard plants among the other stuff, and were harvesting about 0.1 lbs of chard /week total based on our records, which works out to about 1 lb from those four plants over a 60 day period, or $9.97/lb. (!!)  Not nearly up to expectations, but keep in mind that chard wasnt the only thing in the bed (so the whole cost of the light cant be attributed just to chard), and since our fish were stubbornly refusing to grow, these plants were extremely nutrient limited.  Fortunately, the thyme and basil that we grew at the same time cost a lot more at the store than chard, so it might all even out.  

 But, just for kicks, what would the cost be if we filled the grow-bed with dirt, planted all chard, and it grew a little closer to expectations?


We can assume that ten swiss chard plants will fit in the grow-bed since we had four plants in less than half the space.  A generally-accepted representative time-to-harvest for swiss chard is 60 days, although its usually possible to start selectively eating the leaves well before that (which we did).  But if we take a 60-day baseline, and equate one plant to one bunch that youd find at the grocery store, wed have 10 bunches in 60 days.  So, the calculation then becomes $0.17 per day, times 60 days, divided by 10 plants to give $1.00 per plant (or bunch).  Considering that we currently find it for around $1.99/bunch at the grocery store, that seems like a much more reasonable deal.

Generalized equation to figure out the cost of growing a plant under artificial lights, assuming the artificial light is the only cost.  For "C," use the inverse of the number of plants in the bed (e.g., if you had 10 plants in one bed, use 1/10).  Similarly for "G," if you got, e.g., 8 pounds from 10 plants, use 10/8.



Looks like it might be worth giving it another shot at growing some winter greens indoors!  Next time well use real dirt, and wont count on a few anorexic minnows to provide all the fertilizer.  And now that spring is on its way, we probably wont get to this experiment again until the fall, but hang tight!  We wont forget!


Do you grow your own greens indoors during the winter?  How cost effective is it for you?  Let us know in the comments section below!



Jumat, 10 Juni 2016

Economics of Hunting

Growing up in Wisconsin, the deer hunting season was as close to a holiday as one could get without official state sanctioning.  We were enthusiastic participants in the jubilee--countless hours in the woods and swamps waiting for a deer to walk by (watching the antics of squirrels and woodpeckers in the meantime), and countless more hours trying to chase those same deer past uncles and cousins, inventing hare-brained fail-proof strategery on a truck tailgate while eating sandwiches and apples, playing cribbage while cooking celebratory tenderloins, and playing poker late into the night.

It was a family gathering as much as anything, but the question sometimes arose--how did the price of the venison we were currently in the process of procuring compare to something comparable we could buy?  The question has become more poignant now that we now need to buy non-resident licenses at a premium price of 567% of the resident license cost.  This week, we realized we had never actually sat down and calculated it.  Fortunately, that type of calculation is just the kind of thing we do here on this blog.

Time to put on our number-crunching hats and look at some scenarios.  And time to make a spreadsheet!

First, here are the numbers we used, broken up into five scenarios.  Scenarios 1a and 1b incorporate the cost of a low-end, but serviceable rifle ($300 on sale from the local farm store), and a $25 box of shells for an initial sight-in.  Those costs are assumed to be divided up evenly over the first five years, and work out to $65 for years 1-5.  Another four shells are included for a tune-up and the kill shot, at a cost of $5.  (For bow-hunting, a likely-non-reusable arrow and a possibly-reusable broadhead could also be approximated at $5, maybe a little more.)  A resident deer license in Wisconsin is $24, and the cost for a typical excursion included travel to the hunting grounds at about 200 miles round trip (calculated at a travel cost of $102, using an approximate GSA mileage rate of $0.51/mile), about $25 in extra food (per person) for donuts, granola bars, celebratory beers, etc., and a processing fee of $85, if we were to take the deer in (Scenario 1a).  The "hanging weight" of the deer is assumed to be 80 lbs, which roughly equates to 110 lb dressed and 140 lb live weights, which are typical for upper midwestern whitetails.


Scenarios 2a and 2b assume that the gun is paid for, and is sighted in and close to accurate.  This is closest to the situation we had growing up. Scenario 3 is closest to our current situation, with $160 for a non-resident license, no travel costs (because Jakes parents now live in a cabin on the hunting grounds), and no processing costs, since well be gosh-darned if we let some careless butcher guy waste a single ounce of that deer.


Scenarios 4a and 4b are for comparison to elk hunting in Colorado, including a drive from the Denver area up to the legendary Flat Tops Range by Yampa (310 miles round trip). The lowest elk processing fee we could find was $275 (others were close to $1.00/lb), and the average field-dressed weight for an elk is in the range of 350 lb.


Scenario 5 is if dear old Dad wanted to drive out from Wisconsin to Colorado for an elk hunt, and also wanted to outsource his elk processing.


The total cost works out to $2-4/lb for Wisconsin whitetail venison, $0.70-$1.50/lb for resident Colorado elk venison, and about $5.69 for non-resident Colorado elk venison, if that non-resident drives from Wisconsin, with the breakdown shown above.  Processing adds about $1/lb to the total cost for the deer, and a little less for the elk.  The lower travel cost from Jakes parents new digs pretty much offsets the increased cost of the non-resident license. (Thanks, mom and dad!)  Unfortunately, it doesnt work out quite as nicely coming to Colorado to hunt elk.



For comparison, the lowest beef prices we could find were about $3.51/lb (composite value from averaging ribeye, filet mignon, back ribs, sirloin, and strip steaks from here; its bolstered by the ribs, but that brings it into the wholesale range recorded by the USDA).  The grocery store conventional beef (averaging prices for hamburger, sirloin, and strip steaks in the weekly ad of our local King Soopers store), came in at $4.92/lb.  Buying grass-fed beef directly from the farmer was marginally higher at $5.23/lb (from averaging prices here, here, here, here, and here).  To give an idea of the range of farm-direct conventional beef, the last link also offers that next to its grass-fed beef, at $4.50/lb. 

So, long story short, hunting venison is generally less expensive than buying beef, especially if you do your own processing and dont have to travel far to hunt.  A corollary is that if you do have to travel, you can probably decrease your price per pound by getting multiple tags to fill on the trip (e.g., elk plus mule deer plus antelope).

Of course, all of the above is predicated on the assumption that the hunt is successful.  Thats not necessarily a given, as the Wisconsin deer hunting and Colorado elk hunting success rates show.  But if you do your homework ahead of time, your odds of success are probably higher than the average.

Practicing by hunting the rare and elusive feed bag target is an important part of the pre-hunt homework, but be careful not to shoot any chickens!


Have you calculated your hunted meat costs?  How do they compare?

 

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