In a good year, we get about 3,000 lb. of potatoes on two tenths of an acre (or so).  That’s just seven and a half tons per acre, not a spectacular yield but we’re proud of it, since we’ve been gardening on the B-horizon at that farm for a good many years, and it takes a long time to build humus in a garden plot — not like pasture, where you’re not removing the organic matter, just transforming it with the help of your animals.   And what does one do with 3,000 lb. of potatoes?  No, we don’t eat 8 lb. of potatoes per day; even when we were ten in family we didn’t eat quite so many.  No, the extra roots — small potatoes, spiked potatoes (hit with the fork in harvest), and supererogatory potatoes left over when the new potato harvest comes in, in all maybe 40% of the total — are ideal pig food.  They are easy to grow — mostly they just want to stay hydrated, and not to be overrun by weeds.  They store well for a long time (last winter’s hogs ate potatoes, and we’re still feeding them to the six piglets we bought in early July).  There’s only one flaw in our system; the food value of potatoes is only about half available when you feed them out raw.  So we’re looking for plans for a passive solar cooker that isn’t too hideous and will function in our regularly overcast region.  Please send us suggestions!