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writing:winter_greenhouses [2025/11/26 22:10] – JacobCoffinWriteswriting:winter_greenhouses [2026/01/02 15:34] (current) – JacobCoffinWrites
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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.
  
   * **[[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.
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       * Downsides: additional work with caring for animals. Possibly more complex structures - as far as I can tell the animals might not be in a pen in the greenhouse but in an adjacent room with cross ventilation.       * Downsides: additional work with caring for animals. Possibly more complex structures - as far as I can tell the animals might not be in a pen in the greenhouse but in an adjacent room with cross ventilation.
   * And absolute worst case, there are [[https://solar.lowtechmagazine.com/2020/09/how-to-make-biomass-energy-sustainable-again/|ways to make wood heat sustainable]] (and to produce biochar using [[https://permacultureprinciples.com/post/rocket-stoves/|rocket stoves]] or [[https://en.wikipedia.org/wiki/Rocket_mass_heater|rocket]] [[https://insteading.com/blog/rocket-mass-heaters/|mass]] [[https://permies.com/w/rmh-builders-guide|heaters]] as a byproduct. This stuff can be tremendously useful in compost, and holds carbon for a comparatively long time.   * And absolute worst case, there are [[https://solar.lowtechmagazine.com/2020/09/how-to-make-biomass-energy-sustainable-again/|ways to make wood heat sustainable]] (and to produce biochar using [[https://permacultureprinciples.com/post/rocket-stoves/|rocket stoves]] or [[https://en.wikipedia.org/wiki/Rocket_mass_heater|rocket]] [[https://insteading.com/blog/rocket-mass-heaters/|mass]] [[https://permies.com/w/rmh-builders-guide|heaters]] as a byproduct. This stuff can be tremendously useful in compost, and holds carbon for a comparatively long time.
 +  * For additional light, low voltage electric lamps (perhaps using salvaged headlights) could do a lot to extend the short daylight hours. Alternatively, [[solar_concentrators|Solar Tubes and Fiberoptic Daylighting Systems]] won't extend the length of the day, but they will capture additional sunlight and redirect it into the greenhouse. Solar tubes are simpler to set up and maintain but don't reach as far, Fiberoptic Daylighting Systems are more mechanically complex but can reach further and capture more light. Either may be useful if the greenhouse isn't sited as optimally as it could be or just needs more light.  
 +    * Some of these systems have been tested for indoor farming - could the basic concept of sheltering the growing space into the earth be taken even further and end with a greenhouse entirely underground, with just ventilation and light capture systems on the surface? 
 +  * There are [[https://smallfarms.cornell.edu/2011/10/soap-bubbles-to-insulate-greenhouses-a-new-approach-to-energy-conservation/|systems for adding temporary insulation between layers of greenhouse plastic by forcing in soap bubbles]], it might be a bit too high-tech and fiddly for some settings but it might be a great fit for others.