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| writing:winter_greenhouses [2025/11/26 21:57] – JacobCoffinWrites | writing:winter_greenhouses [2025/11/28 17:24] (current) – JacobCoffinWrites |
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| **Salvage** | **Salvage** |
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| One of the major cost points in building a walipini is excavating and reinforcing the pit which forms the structure. This work may require an excavator or a lot of time and sweat to do by hand and concrete is expensive (especially environmentally). Structures that meet this general requirement already exist though, and they're fairly common: in-ground swimming pools and basements. Neither is a one-to-one fit for the ideal walipini design, but they have lined, reinforced holes in the ground, stairs for access, and, in the case of basements, may already have drains installed. Swimming pools are expensive and wasteful to maintain, requiring large amounts of water, chemicals, labor, and electricity to keep clean. Furthermore, damage to a pool which prevents its use for holding water (like expensive cracks) don't prevent it from being repurposed as a walipini. A few people have already done [[https://www.urbangardensweb.com/2017/08/26/transform-disused-swimming-pool-garden/|absolutely]] beautiful swimming pool -> walipini conversions, but a recovering society might see a huge number of these conversions for utilitarian reasons. | One of the major cost points in building a walipini is excavating and reinforcing the pit which forms the structure. This work may require an excavator or a lot of time and sweat to do by hand and concrete is expensive (especially environmentally). Structures that meet this general requirement already exist though, and they're fairly common: in-ground swimming pools and basements. Neither is a one-to-one fit for the ideal walipini design, but they have lined, reinforced holes in the ground, stairs for access, and, in the case of basements, may already have drains installed. Swimming pools are expensive and wasteful to maintain, requiring large amounts of water, as well as chemicals, labor, and electricity to keep clean. Furthermore, damage to a pool which prevents its use for holding water (like expensive cracks) don't prevent it from being repurposed as a walipini. A few people have already done [[https://m.youtube.com/watch?v=ZqeJamSyYVg&pp=0gcJCR4Bo7VqN5tD|absolutely beautiful]] [[https://www.urbangardensweb.com/2017/08/26/transform-disused-swimming-pool-garden/|swimming pool -> walipini]] [[https://springbird.land/greenhouse-update-mission-completed/|conversions]], but a recovering society might see a huge number of these conversions out of necessity. |
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| A residential basement is a bit less accessible, but they still become available fairly often, in the event of fire or demolition IRL, they're often left open for months or years. In a world where car-dependent regions are becoming less viable, and [[deconstruction|deconstruction]] efforts are disassembling abandoned buildings and salvaging the materials for reuse, we could even see some suburban neighborhoods repurposed into rows of walipini greenhouses. | A residential basement is a bit less accessible, but they still become available fairly often. In the event of fire or demolition they're often left open for months or years. In a world where car-dependent regions are becoming less viable, and [[deconstruction|deconstruction]] efforts are disassembling abandoned buildings and salvaging the materials for reuse, we could even see some suburban neighborhoods repurposed into rows of walipini greenhouses. |
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| Other salvage: Like with earthships, much of the modern homesteading-based walipini building scene places a heavy emphasis on repurposing existing //stuff//. Walipini pits are frequently reinforced with stacked old tires packed with rammed earth, and salvaged lumber, windows, thermostats/fans, wiring, and lights are all used wherever possible in their construction. This could be pushed even further in a solarpunk setting; perhaps the massive windows from car dealerships could be used for the sun-facing wall, | Other salvage: Like with earthships, much of the modern homesteading-based walipini building scene places a heavy emphasis on repurposing existing //stuff//. Walipini pits are frequently reinforced with stacked old tires packed with rammed earth, and salvaged lumber, windows, thermostats/fans, wiring, and lights are all used wherever possible in their construction. This could be pushed even further in a solarpunk setting; perhaps the massive windows from car dealerships could be used for the sun-facing wall. |
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| Downsides: | Downsides: |
| * **Engulfment** - many images online show walipinis from inside with bare earth walls, with no reinforcement. This means the structure is essentially an unlined hole in the ground whose walls could decide to relocate at any time. OSHA and other safety organizations define this class of dangers as engulfment hazards. Engulfment occurs when a person becomes trapped by flowable materials — such as soil, sand, or grain — that can move rapidly, collapse without warning, or block escape routes. These incidents often lead to injury or death by strangulation, constriction, crushing, or suffocation. They are most commonly associated with confined spaces like trenches, silos, tanks, and storage bins. Engulfment hazards can still pose a serious risk even if your head is above the walls of the hole, as the soil can flow and settle around your chest and prevent inhalation, leading to suffocation. This pressure can also cause constriction/crush injury to buried parts of your body. Remember to [[https://www.osha.gov/sites/default/files/publications/osha2226.pdf|shore, slope, or bench]] any excavation for safety! | * **Engulfment** - many images online show walipinis from inside with bare earth walls, with no reinforcement. This means the structure is essentially an unlined hole in the ground whose walls could decide to relocate at any time. OSHA and other safety organizations define this class of dangers as engulfment hazards. Engulfment occurs when a person becomes trapped by flowable materials — such as soil, sand, or grain — that can move rapidly, collapse without warning, or block escape routes. These incidents often lead to injury or death by strangulation, constriction, crushing, or suffocation. They are most commonly associated with confined spaces like trenches, silos, tanks, and storage bins. Engulfment hazards can still pose a serious risk even if your head is above the walls of the hole, as the soil can flow and settle around your chest and prevent inhalation, leading to suffocation. This pressure can also cause constriction/crush injury to buried parts of your body. Remember to [[https://www.osha.gov/sites/default/files/publications/osha2226.pdf|shore, slope, or bench]] any excavation for safety! |
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| * **Heavier-Than-Air Gasses** In workplace safety terms, an enclosed, sunken structure like a walipini becomes a “confined space” where heavier-than-air gases can pool, causing a serious danger to anyone who enters. Such gases could originate from the drain system or flow from surrounding ground, such as adjacent leaking propane or sewage pipes. But it could also come from decomposition within the greenhouse, such as from compost. [[https://web.archive.org/web/20140209092347/http://sleepycity.net/approach-to-draining|Urban Explorers]], First Responders, and [[https://www.naspweb.com/blog/when-invisible-danger-strikes-the-perils-of-hydrogen-sulfide-in-confined-spaces/|City Maintenance Personnel]] know the risks of Hydrogen Sulfide (H2S) in a confined space - the gas is produced by the anaerobic decomposition of organic matter (such as you might find in sewage or storm drains, or poorly-managed compost heaps) and pools in low areas. With a heavy enough concentration the gas can knock you out immediately, sometimes leading to tragic chains of deaths as would-be rescuers are also overcome. Similar tragedies have also happened when gasses produced by rotting potatoes pooled in residential basements. The good news here is that this is preventable through detection and ventilation. Detectors are commercially available and fans and ductwork can draw air from the lowest point in the structure (usually the cold sump) out of the walipini. If the walipini is built into a hillside, you may also be able to include a passive ventilation system by using a pipe as a drain running downhill from the lowest point in the greenhouse to the outside. | * **Heavier-Than-Air Gasses** In workplace safety terms, an enclosed, sunken structure like a walipini becomes a “confined space” where heavier-than-air gases can pool, causing a serious danger to anyone who enters. Such gases could originate from the drain system or flow from surrounding ground, such as adjacent leaking propane or sewage pipes. But it could also come from decomposition within the greenhouse, such as from compost. [[https://web.archive.org/web/20140209092347/http://sleepycity.net/approach-to-draining|Urban Explorers]], First Responders, and [[https://www.naspweb.com/blog/when-invisible-danger-strikes-the-perils-of-hydrogen-sulfide-in-confined-spaces/|City Maintenance Personnel]] know the risks of Hydrogen Sulfide (H2S) in a confined space - the gas is produced by the anaerobic decomposition of organic matter (such as you might find in sewage or storm drains, or poorly-managed compost heaps) and pools in low areas. With a heavy enough concentration the gas can knock you out immediately, sometimes leading to tragic chains of deaths as would-be rescuers are also overcome. Similar tragedies have also happened when gasses produced by rotting potatoes pooled in residential basements. The good news here is that this is preventable through detection and ventilation. Detectors are commercially available and fans and ductwork can draw air from the lowest point in the structure (usually the cold sump) out of the walipini. If the walipini is built into a hillside, you may also be able to include a passive ventilation system by using a pipe as a drain running downhill from the lowest point in the greenhouse to the outside. Ventilation is additionally useful in summer when overheating can become an issue |
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| There are several ways to produce heat that also provide CO2. This is helpful because it accelerates plant growth and boosts crop yields, and makes up for the | There are several ways to produce heat that also provide CO2. This is helpful because it accelerates plant growth and boosts crop yields, and makes up for the lack of CO2 produced by gas heaters in normal greenhouses. |
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| * **[[https://commonwealthurbanfarms.com/wp-content/uploads/2021/10/CommonWealth-Compost-as-heat-source-Guide-2021.pdf|Compost]]** - Composting is an important part of agriculture likely already present wherever there's a greenhouse. As microorganisms break down biodegradable materials they naturally produces heat and CO2. A compost bin can reach 140 degrees Fahrenheit or more inside the pile while it is in the hottest phase of decomposition. The effectiveness of the compost-as-heat depends on the amount of compost and how well the greenhouse is insulated - in some cases it may not be enough on its own to heat an entire greenhouse but might be built into the lower part of seedling beds to keep them warm and get a jump start on the growing season. | * **[[https://commonwealthurbanfarms.com/wp-content/uploads/2021/10/CommonWealth-Compost-as-heat-source-Guide-2021.pdf|Compost]]** - Composting is an important part of agriculture likely already present wherever there's a greenhouse. As microorganisms break down biodegradable materials they naturally produces heat and CO2. A compost bin can reach 140 degrees Fahrenheit or more inside the pile while it is in the hottest phase of decomposition. The effectiveness of the compost-as-heat depends on the amount of compost and how well the greenhouse is insulated - in some cases it may not be enough on its own to heat an entire greenhouse but might be built into the lower part of seedling beds to keep them warm and get a jump start on the growing season. |
| * The downsides here are that using compost as heat requires some planning and monitoring - it's less convenient than a commercial heater. Additionally there's some additional risk: modern greenhouses are sometimes used to isolate and protect plants from threats like bugs and blights outside, and bringing compost into the greenhouse (especially in an open container) can cross-contaminate. If this is a concern setting up [[https://smallfarms.cornell.edu/2012/10/compost-power/|a fluid exchange system with an outdoor compost pile]] might make more sense. | * The downsides here are that using compost as heat requires some planning and monitoring - it's less convenient than a commercial heater. Additionally there's some additional risk: modern greenhouses are sometimes used to isolate and protect plants from threats like bugs and blights outside, and bringing compost into the greenhouse (especially in an open container) can cross-contaminate. If this is a concern setting up [[https://smallfarms.cornell.edu/2012/10/compost-power/|a fluid exchange system with an outdoor compost pile]] might make more sense. |
| * **[[https://peasantpolis.substack.com/p/heating-our-greenhouse-with-manure|Manure]]** The use of manure for heating small-scale greenhouses dates back several centuries in Europe, and in China it was practiced 2,000 years ago. A greenhouse can be [[https://inthelivingkitchen.wordpress.com/2010/03/12/heating-things-up/|entirely heated by compost]] if it is well-insulated, and that the method drastically enriches the CO2-levels in the soil and in the greenhouse air. I haven't found a good breakdown on if there's a functional difference between using animal manure vs plant matter but all the ones I've found that claim decomposition meets all their heat needs appear to be using at least a mix of manure if not primarily that. | * For a bigger scale option, [[https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/2020-01/swot-foodscrapmanagement.pdf|centralized municipal composting]] sometimes uses long covered windrows with aeration to keep the decomposition from going anerobic. If the aeration is set up as a negative pressure system which sucks air from the compost windrow to pull in fresh air - you could divert the warm, CO2-heavy air into the greenhouses to boost plant growth without burning fuel. |
| | * **[[https://peasantpolis.substack.com/p/heating-our-greenhouse-with-manure|Manure]]** The use of manure for heating small-scale greenhouses dates back several centuries in Europe, and in China it was practiced 2,000 years ago. A greenhouse can be [[https://inthelivingkitchen.wordpress.com/2010/03/12/heating-things-up/|entirely heated by manure]] if it is well-insulated, and that the method drastically enriches the CO2-levels in the soil and in the greenhouse air. I haven't found a good breakdown on if there's a functional difference between using animal manure vs plant matter but all the ones I've found that claim decomposition meets all their heat needs appear to be using at least a mix of manure if not primarily that. |
| * Downsides: still not as convenient as a furnace. Comparatively bad smell (though a layer of charcoal can help). Involves animals in agriculture which can be done ethically but vegan writers may prefer to avoid. | * Downsides: still not as convenient as a furnace. Comparatively bad smell (though a layer of charcoal can help). Involves animals in agriculture which can be done ethically but vegan writers may prefer to avoid. |
| * Manure-related fun fact: colonial farmers in the New England region of the US [[http://www.onenewengland.com/article.php?id=94|added manure basements to their ever-changing barn designs]], making removal and storage of animal waste easier (just shovel it down a hatch right indoors). The heat of this manure decomposing kept the barn (and especially its foundation) warm. As the barns fell out of use, part of their rapid collapse came from fieldstone foundations which were no longer protected from expanding ice. | * Manure-related fun fact: colonial farmers in the New England region of the US [[http://www.onenewengland.com/article.php?id=94|added manure basements to their ever-changing barn designs]], making removal and storage of animal waste easier (just shovel it down a hatch right indoors). The heat of this manure decomposing kept the barn (and especially its foundation) warm. As the barns fell out of use, part of their rapid collapse came from fieldstone foundations which were no longer protected from expanding ice. |
