625,000 Calories on 1/10th Acre

Well we are officially 3 weeks in to the Great Potato Harvest, and the Yukon Golds are about done. They are sizing up nicely -with a few rare lunkers coming in at almost a full pound –each. With today’s take of 170 lbs we are officially at 575lbs in, and my best guess is about 5-600#’s of Carolas left, on top of the last 150#’s of Yukons. Add in a hundred combined of Green Mountain and Buttes and I just might break 1500#’s yet. The pic is from the first batch of baby Carolas 2 weeks ago they are continuing to add weight -I am getting about 25% more poundage per Carola hill than the average Yukon hill.

On top of that the Carolas are living up to their billing as the “Brandeywine” of potatoes. Super moist and tender, they all but melt in your mouth after roasting, frying in a skillet, or soaking in a wet curry. The Yukons are much firmer and have been perfect for our potato salads. It took 3 weeks, but we are slackening our passion for potatoes -we had gone almost 2 weeks with them at 2 of 3 meals per day. Still, they are carrying a meal a day most days.

And that is why I like spuds -they are what I call a “calorie crop”. It is difficult to just eat Peppers, Cucumbers, or Tomatoes etc as a main course -even for vegetarians. But Corn, Potatoes, Squash etc can anchor a meal. It is also said that Potatoes pack more energy per acre than any other crop. My 4500 sq ft (1/10th acre) will net 625,000 calories if my figures are right (26 calories per ounce for 1500 lbs). That is ALOT of calories!! Considering this is harvesting at baby weight, and/or using low yielding varieties like Yukon I don’t feel bad about being significantly off the typical yields of 30,000 lbs per acre conventional. A field of Purple Viking left to maturity would come very close to that.

So next time That Guy at work says we can’t feed the world organically, shove the figure of 6.3 million calories per acre at them and be comfortable that there is still 4 million calories of production on the table!!


13 Responses

  1. Fantastic! I just harvested half my potato plot and ended up with about 12 lbs from 20 square feet, the yukon yield was pretty sad, but the caribes were making tubers at almost two to one yukon. I may try carolas and caribe’s next year, and thanks again for the moose tuber tip.

    Did you end up with any scab? a couple of mine had spots but nothing too bad.

    And you are definitely right about potatoes being a means of feeding a lot from a few acres. Most of the poor tennant farmers in Ireland were only given an acre to feed their family for the year by the landlord. Potatoes were one of the few things that could be grown to reliably provide calories for a family for a year. Everyone knows what happened to the potato crops eventually, but barring catastrophe spuds are a calorie/square foot powerhouse. The situation was a recipe for disaster, most farmers were only using one or two varieties, and forget crop rotation when you are using practically your whole allotment to get by.

    Throw this one at your co-worker, industrial agriculture depletes the land at a faster pace, so when taken on a longer timescale, the only way we can feed the world is organically.

  2. Rutabagas and Jerusalem artichokes are also quite good at calories-per-acre. Calculations here

  3. Rob,

    Another place to send those people who think we can’t feed the world organically might be the Science Barge in NYC (http://nysunworks.org/?page_id=9). If you want to find out a little information about it without actually going to NY, the New York Academy of Sciences just did a Podcast all about it. You can hear from a couple of the staff there and get a taste of what you’ll see and hear about on the tour.
    You can listen to the podcast here: http://www.nyas.org/snc/podcastdetail.asp?id=1834

  4. On rain barrels and water harvest in the Seattle PI

    Saving rain: How much is too much?
    Collecting large amount runs afoul of ‘archaic’ law


  5. They look fantastic. But now you have me worried that I should already be harvesting my potatoes! I’ve got La Ratte, All Blue, Kennebec and Sangres out there. It’s my first year growing them, and I’m always a little unsure about root crops. It’s just so hard to know what’s going on down there…. Must find the time to dig some very soon!

    By the way, I have heard that leeks can actually beat potatoes in the calories/acre contest. I don’t know who said so, or how they calculated that. But they are very sweet and can be grown pretty densely, so I suppose it’s possible. I’ve got a long row of them in the garden too.


  6. What was your source for the Carola potato sets, Rob?

  7. Ed, the were purchased from Fedco (Moose Tubers): good service, great selection, very fair price. Plus they are a wicked good source for All Things Organic.

    Kate, THANKS! I plant EARLY to stretch the season and take advantage of the June rains (rather than curse them when I can’t get into the fields) -these were planted in April Wk 4 (Zone 5b). Carolas are an “early” mid and these are only half grown. I will harvest these Carolas over a 4-5 week period starting with golf ball sized babies and finish with 3/4# lunkers. Yukons are the same (but start 3 weeks earlier and finish sooner. I also plant late varieties (Butte and Green Mountain) to further stretch the season by another 2-3 weeks. I can realisticly harvest spuds from late June through mid September this way from one planting.. Early plantings have more issues with Colorado potato beetle -but I have the luxury of rotating fields that are hundreds of yards apart separated by BIG windbreaks. Planting this early you could get two crops in on the smae chunk of land if you use Carolas or Caribe -that is pushing the land VERY hard though.

    I might have to call shinanagans on the leek calorie quote. Potatoes are about a calorie a gram -and you get 30,000#’s an acre (13,500,000 grams) but leeks, while yielding about 20% more tonnage per acre (37,000#’s) take about 5 grams to equal a calorie and come out at only 3,400,000 calories per acre -about 65% less. Quotes based on Google searches so take it for what its worth.

    That said, I highly recommend growing them together – all the better to make leek and potato soup! YUM!

  8. Harvested my mini-potato patch yesterday … got 1.25lb per square foot. Respectable, I think, even if it’s nowhere near your 625,000 calories. šŸ™‚

    Any suggestions for storing them this early? Last year, I put them in a bucket of peat in the garage, but the garage is 100 degrees in the afternoon this time of year. Is the basement cool enough?

  9. 1.25#/sq ft is very respectable. I am getting that per row foot, but that is about a quarter your yield. If you could upsize that yeild to an acre you would be at about 24,000,000 calories per acre -you are about 80% better yielding than Big Ag on spuds right now.

    Respectable? You bet!

    Storing them this early involves getting them as cool as possible. If your basement is under 70 put them there in your peat bucket. 50 is perfect. 100 in the garage = not so good! I am getting 2-3 weeks in 80 degrees inside just sitting there in the doorway to our garage. They might last longer, but we keep eating them!

  10. […] could produce about 100,000#’s of potatoes equating to roughly 43Ā millionĀ calories at theĀ yieldsĀ IĀ achievedĀ this past year. Ā Of course I would never plant that much of one crop! Ā  The point is to show […]

  11. So according to my calculations, you could almost feed one person for a year on that. Per year, an average calorie count is about 2000/day, which makes 730000 per year. A hard-working subsistence farmer would expect to burn 5000/day though, which brings the total to 1825000. Which means you would need to multiply that yield by 3 to feed one person for a year.

    That’s 3th’s, or 1/3rd acre you’d need per person. But then, since you are constantly withdrawing so many nutrients out of the soil, how would you replace them? Would you use humanure? Because otherwise you’d flush most of the nutrients away, and that certainly wouldn’t be sustainable unless you retrieved them somehow.

  12. Humanure would certainly close the loop, but of course your composting technique needs to be Top Notch. Cover Cropping with rye/vetch would replace some of the nutrients – running chickens through the Rye each spring would replenish quite a bit more. The chickens would also provide substantial nutrients/calories in areas that the spuds are lacking: fats and protein (we’ll keep this vegetarian, but not vegan for now), adding a tre vegetable crop as a third component of the rotation would fill in the rest (vitamins).

    .3 acres could house at least 2 dozen chickens forever (grow winter wheat on the veggie plot and harvest that the following year for supplemental chicken feed -at least 500lbs), producing ,on average, 72 eggs per week for 9 months of the year (more in summer, less in fall) – adding up to another 194000 critical calories (36 weeks x 72 eggs x 75 calories per egg) and solving most of your fertilizer problem. Eat some of the chickens and you have even more calories, but less fertilizer next year. You would need at least .6 acres to do this (some place to keep the hens while you grow your spuds). But you should really rest the soil more than one yar before replanting spuds, so a full acre would be needed at minimum with melons/greens/brassicas as an alternate crop in the final .3. That .3 would produce less calories, but more nutrition, getting us up somewhere in the 2,000,000 calorie mark (625k x 3 + 194k + something for veggies) for one acre with 33% in grazed cover crop/pasture. A 7 year rotation would be ideal.

    Also, if you are only working 1 acre of land, and only .6 of that is in crop, you would not burn anywhere near 5000 calories a day. I am a very vigorous part-time farmer and I gain weight (not the good kind) on anything over 3200 – and that is only in the summer -winter calorie loads drop quickly.

    There is no doubt about intensive farming being able to make a surplus (yes Organic Farming CAN feed the world) – the question is can it do it sustainably. Managing your fields for long term fertility loads rather than yields is the key – yields averaged over decades should be the goal, or average yield vs input calorie (counting fuel and fertilizer) would be even better. As Oil begins its descent, these will become critical questions. Organic farming will be the ONLY farming by the time my kids are having children – we need to skill up in one generation.

    There, my post length comment is done! Check out my page on Eco Vegetarianism for a much more lengthy write up on my dream Sustainable farm.

  13. I am trying to understand this idea of perpetual fertility. The sun provides the energy, so that is where the carbohydrates in the potatoes come from. Of the other 16 essential elements, nitrogen can be (slowly) fixed from the air (air is almost 80% nitrogen). The rest come from the soil, whether you fetch them a bit deeper with rye, or fetch them with chicken fodder and then use the processed guano.

    Even if you rest the land, that allows some weeds to grow, and they might fetch other elements from deeper in the soil – but you’d be hard pressed to fetch anything deeper than 2-3 metres down because that’s about as long as the longest comfrey roots are. Otherwise you have to plant trees and mine the really deep elements: some Acacias have been known to go down 60 metres, but that would have a very long growing time.

    Those lements then go into your body, or the bodies of the people at the market, and many of those elements go out into the sewage system. The only way this system is sustainable is to recover those elements from those people, or the sewage system. Also, each new crop will see a certain amount of elements (including the critical phosphorous and potassium) leach deeper than the roots will reach.

    My interest in all this is: can we do without fertilizer? Trees mine elements just like we do, but they do it much much slower, and we have a large human population. I have seen a lot of people imply that permaculture, grow biointensive, or organic farming can somehow manufacture elements from nothing. Ancient people fetched mud from rivers that eroded mountain rocks, gleaning essential elements from there, but are there enough rivers with enough fertile mud close enough to our cities?

    I have seen “organic rock dust” and “organic fertilizer” being sold, but again, how long can that go on after the oil decline? Mud and rock are very heavy and take a lot of energy to transport and grind.

    I am a big fan of permaculture, and have started my own project growing over 40 types of edible plant on a tiny bit of land, but to say that it is “sustainable”, I really need to understand how.

    Here’s one reference on this issue:

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