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Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

lowtechmagazine.com

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Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#61

Post by wenc »

Scoundreller wrote: post #29
paypalcust83 wrote: post #7

Climate-controlled cultivation will likely become a necessity for food production as climate change intensifies. Spain, South Africa, many Middle Eastern and other countries are already heavily reliant on greenhouses. Also given that megadroughts, floods, and hurricanes are likely to be the new normal, sufficient capacities of solar-powered desalination will be important to sustain food production levels. My main imm…

Problem is that greenhouses are the most laborious. Can’t drive a tractor through to plant and pick everything.

Instead of a tractor, wouldn't robotics work? [1]

The scale would be much smaller, and the cost higher of course.

[1] https://www.postscapes.com/smart-greenhouse-robotics-materia...

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#62

Post by jfk13 »

pjc50 wrote: post #54
yesbabyyes wrote: post #39

Earlier quoted context omitted.

There are in fact about 7.8 billion of us. I believe we will have to change from this Growing part of your own food is a good idea. We should all plant some potatoes this year – a not so laborious way of producing nutritious food.

Kind of Maoist and inefficient to have all your specially trained valuable first world labour do manual work, badly.

As a specially trained valuable first world labourer -- at least, my employer seems to think I'm worth a salary -- I find growing my own potatoes (and a few other things) a welcome break from my desk and screen.

I'm sure my garden is nowhere near as efficient as a real farmer could make it, but that's hardly the point. And a few rows of potatoes (even with my inefficient management), are a much more productive use of the land than a typical suburban lawn.

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#63

Post by ip26 »

Scoundreller wrote: post #29
paypalcust83 wrote: post #7

Climate-controlled cultivation will likely become a necessity for food production as climate change intensifies. Spain, South Africa, many Middle Eastern and other countries are already heavily reliant on greenhouses. Also given that megadroughts, floods, and hurricanes are likely to be the new normal, sufficient capacities of solar-powered desalination will be important to sustain food production levels. My main imm…

Problem is that greenhouses are the most laborious. Can’t drive a tractor through to plant and pick everything.

Some of the industrial scale "greenhouses" I see are PVC frames with sheet plastic. Lift them right off come harvest.

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#64

Post by loeg »

Some of these techniques are still common to produce hardy plants or increase yields with low land use. "Creeping" is also called low-stress training, and the extreme form is sometimes colloquially called "screen of green." SoG is so-called because you essentially put a net at a fixed height and force the plants leaves to all be at that exact height, attempting to maximize photosynthesis efficiency. (Really hot peppers varieties take some babying to thrive. These techniques are also popular in the marijuana community.)

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#65

Post by loeg »

jfk13 wrote: post #62
pjc50 wrote: post #54

Earlier quoted context omitted.

Kind of Maoist and inefficient to have all your specially trained valuable first world labour do manual work, badly.

As a specially trained valuable first world labourer -- at least, my employer seems to think I'm worth a salary -- I find growing my own potatoes (and a few other things) a welcome break from my desk and screen. I'm sure my garden is nowhere near as efficient as a real farmer could make it, but that's hardly the point. And a few rows of potatoes (even with my inefficient management), are a much more productive use of…

Do it if you enjoy it, but that isn't the point GP was making or responding to. (I also maintain a small garden, FWIW.)

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#66

Post by hutzlibu »

wenc wrote: post #61
Scoundreller wrote: post #29

Earlier quoted context omitted.

Problem is that greenhouses are the most laborious. Can’t drive a tractor through to plant and pick everything.

Instead of a tractor, wouldn't robotics work? [1] The scale would be much smaller, and the cost higher of course. [1] https://www.postscapes.com/smart-greenhouse-robotics-materia...

The technic is pretty awesome, but in the video with tomato harvesting ... the robot is about a 100 times slower than a human at picking tomatos. So while there is potential for it, it does not seem ready yet. At least not for the real economy, where manual labour is still quite cheap.

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#67

Post by SECProto »

koheripbal wrote: post #59
tathougies wrote: post #22

Earlier quoted context omitted.

The Europeans also used 'fruit walls'. I'm thinking of setting up one in Portland. Basically a brick wall that you espalier a fruit tree to. You redirect your chimney floo or hot water pipes through the wall to keep it warmer than the surroundings in the winter. I'm hoping to be able to grow frost-sensitive hardy citrus. https://www.lowtechmagazine.com/2015/12/fruit-walls-urban-fa...

The problem is that neither your chimney nor hot water pipes are continually piping heat. So the transient effect of the warm/cold cycles would likely make frostbite even worse. ...and leaving those heat sources on continually... well... that's very energy inefficient, to say the least.

The brick works as a thermal battery - if it's cold, you're heating your house, and the intermittent exhaust is keeping the brick warm. If you're not heating, well it's not cold so the brick temperature doesn't matter much.

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#68

Post by georgeoliver »

DeathArrow wrote: post #41
georgeoliver wrote: post #31

Where I grew up (41.3 deg N, on the Atlantic coast) I was always amazed by our neighbor, who would bury his ~15 foot tall fig tree every year to protect it from freezing. For some reason in my child mind it seemed to defy the laws of nature, though of course it was quite the opposite!

Where I live in Eastern Europe (44°26′7″), we have acclimatized fig trees. And we have temperatures as low as -20C or even -25C (-4 and -13 Fahrenheit).

My parents who still live in the same house do have a small fig tree they don't bury, and my mother's parents a hundred miles south had a larger one in their backyard. I don't know if burying fig trees in that climate is necessary to be honest, maybe it was just a practice my neighbor brought with him (he was Italian as well).

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#69

Post by myself248 »

hyperpallium wrote: post #42
hirundo wrote: post #30

"Training small citrus plants was key to extending their cultivation across all regions of the Black Sea coast, where until then it had been impossible. This was achieved by pruning and guiding citrus plants into a creeping form, which reduced their height to a mere 25 cm." People complain about cubicle farms, but there's so much we can do to train workers to be productive in them, if we start them young enough.

> pruning Do IT workers really need legs?

Y'all need to watch Sorry To Bother You. No spoilers.

Re: Fruit Trenches: Cultivating Subtropical Plants in Freezing Temperatures

#70

Post by floatrock »

koheripbal wrote: post #59
tathougies wrote: post #22

Earlier quoted context omitted.

The Europeans also used 'fruit walls'. I'm thinking of setting up one in Portland. Basically a brick wall that you espalier a fruit tree to. You redirect your chimney floo or hot water pipes through the wall to keep it warmer than the surroundings in the winter. I'm hoping to be able to grow frost-sensitive hardy citrus. https://www.lowtechmagazine.com/2015/12/fruit-walls-urban-fa...

The problem is that neither your chimney nor hot water pipes are continually piping heat. So the transient effect of the warm/cold cycles would likely make frostbite even worse. ...and leaving those heat sources on continually... well... that's very energy inefficient, to say the least.

Idea behind the brick is to add thermal mass -- it stays hot once it gets hot in the same way a freight train stays in motion once it gets going.

This is often done on north-facing walls in greenhouses. In winter when the sun is low, the thermal mass gets a lot of light and absorbs it as heat. Then at night it releases it to balance out nighttime lows. In summer when the sun is high up, because it's a wall there's less surface area that absorbs the radiation, so it's self-regulating to a degree.

Same idea is even used for seasonal thermal storage. Look up "earth batteries" on youtube, usually it's permaculture folks. Basically, put air circulation pipes a couple feet below a greenhouse. In the summer, you flush your (too hot) hot air through it, the ground absorbs the heat, and you cool off your greenhouse. In the winter, the same process absorbs some of the heat out of the ground. Some numbers I've heard is a greenhouse can stay at 50 degrees when it's -20 outside. Basically same idea as a geothermal heat pump, but much simpler because all you need is a blower fan and some pvc.

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