Compost heating is a sustainable and cost-effective way to utilize earthly resources and save time and money. To incorporate compost into your greenhouse’s heating system, create a compost bed and incorporate it into the heating system. This method harnesses the natural heat produced by composting. For home gardeners, heating a greenhouse with compost can be a relatively simple process. To ensure effective heating, get the ratio of compost volume to the size of your greenhouse correct. A compost pile or bin that is too small for your greenhouse will have a negative impact on the greenhouse’s temperature.
Modern methods use water flow pipes buried underground to pass heat from the compost pile to the greenhouse. Plan your location carefully ahead of time to ensure you are close to the greenhouse you will be heating. Compost heating capitalizes on the heat produced during the decomposition of organic material, raising your minimum greenhouse temperature. Setting up a compost pile with a 1-cubic yard compost pile for every 23 square feet of greenhouse space will give your DIY backyard greenhouse a cozy internal temperature boost of around 23°F to 35°F above the outside nighttime winter temperature.
Gardeners can use existing compost bins to warm specific areas or implement trench composting, which allows them to stagger row heat. A compost bin can reach 140 degrees or more inside the pile during its hottest phase of decomposition. Some of this heat rises upward from the pile. Hot composting produces a lot of heat, with an internal temperature of up to 160 degrees when properly cared for. The manure is left to compost, and the heat generated is vented into the other half of the hoop house to provide heat.
📹 FREE passive heating a greenhouse with compost
I’m experimenting with this technique of using the heat from a compost pile to keep a greenhouse warm in Winter.
Can compost heat a greenhouse?
The practice of composting in a greenhouse offers a multitude of advantages, including the ability to maintain optimal temperatures for fruit trees and vegetables, stimulate plant growth, enhance soil quality, and provide a consistent supply of nutrient-rich compost throughout the year. In addition to increasing soil and air temperature, the process of composting also enriches plants with decomposing material.
Does turning compost heat it up?
Composting involves the process of decomposing organic matter in a pile, which is then turned or mixed to restore the temperature. This process is called “curing” or maturation, where mesophilic microbes take over the decomposition process. During this phase, the compost temperature remains close to ambient, but chemical reactions continue to make the remaining organic matter more stable and suitable for plant use. The temperature during composting depends on the amount of heat produced by microorganisms and the amount lost through conduction, convection, and radiation.
Conduction transfers energy from atoms to atoms, while convection transfers heat by moving a fluid like air or water. When compost gets hot, warm air rises within the system, causing a steady but slow movement of heated air upwards through the compost and out the top. Some composting systems use forced convection, driven by blowers or fans, which increases the rates of both conductive and convective heat losses. Much of the energy transfer is in the form of latent heat required to evaporate water.
How to make a compost heater?
The Pain Mound, invented by French farmer Jean Pain in the 1970s, is a large pile of woody biomass, or mulch, made of woodchips and sawdust surrounded by a ring of hay bales for structure and insulation. As the Pain Mound decomposes, heat is produced and harnessed using a hydronic loop. The heat can be used to build soil after 18 months.
To lay out the Mound, stake out a circle approximately 12 feet in diameter, purchase hay bales from a local farm, collect fallen trees and branches, and rent a chipper. A load of sawdust can be procured from a local sawmill for a nominal fee.
To create a Hay Bale Backstop and Add Aeration, lay 15 feet of perforated 4″ tubing at the bottom of the mound, with each end protruding out of the perimeter. Create a “backstop” of haybales to catch the woodchips as they are thrown from the chipper into the mound. Chip a layer of woodchips approximately 1 inch high into the mound on top of the aeration pipe.
How quickly should compost heat up?
A compost pile should be built correctly to heat up within 24 to 36 hours to the ideal temperature of 141°F to 155°F, which kills weed seeds and disease pathogens. It should maintain this temperature for several days to a week or longer. A compost thermometer should be used to monitor the temperature, and if it drops or gets hotter than 160°F, it should be turned again and watered. A hot pile takes more effort but produces compost more quickly, taking weeks to months.
A cold pile requires minimal effort but may take a year or two to produce compost. The time needed for finished compost depends on the materials in the pile and the size of the particles. Avoid putting in weeds that have gone to seed or diseased plants, as without high temperatures, they spread harmful bacteria around the landscape.
How do I make my compost bin hotter?
Compost piles generate heat due to the increased volume of materials, which provides more space and resources for bacteria to colonize and consume. To increase the heat, increase the volume of materials, maintain moisture, strategically aerate, monitor your thermometer, and observe microorganisms at work. Contrary to popular belief, compost piles do not heat up or drop due to atmospheric conditions, but rather due to heat generation by specialized bacterial populations.
Increased bacterial population density leads to faster decomposition due to rapid consumption of nitrogen, carbon, moisture, and oxygen. Temperature spikes are only hot for a finite period, with peak temperatures rarely lasting more than a week. Many composters aim to achieve multiple temperature spikes over several months to neutralize weed seeds and produce finished compost in a shorter time.
How long will a compost pile produce heat?
A compost pile should be built correctly to heat up within 24 to 36 hours to the ideal temperature of 141°F to 155°F, which kills weed seeds and disease pathogens. It should maintain this temperature for several days to a week or longer. A compost thermometer should be used to monitor the temperature, and if it drops or gets hotter than 160°F, it should be turned again and watered. A hot pile takes more effort but produces compost more quickly, taking weeks to months.
A cold pile requires minimal effort but may take a year or two to produce compost. The time needed for finished compost depends on the materials in the pile and the size of the particles. Avoid putting in weeds that have gone to seed or diseased plants, as without high temperatures, they spread harmful bacteria around the landscape.
How compost can be used to generate heat?
The traditional compost heater uses a large compost heap with a spiral water hose to warm a house. The heap must contain at least 8, 000 liters of biomass to maintain a temperature during winter. Chipped wood is piled up and passed through a water hose. A microbiological degradation process generates heat for up to 24 months, producing hot water that is fed to a heating circuit. The activity of microorganisms can be regulated by moisture content.
Can compost get hot enough to start a fire?
Compost fires can occur in large dry heaps or haystacks, especially those over 2×2 meters. The damp inner core of these piles can create heat, which is not quickly escaped due to self-insulating materials. This heat can cause self-oxidation heating, pushing the temperature up to 120°C and potentially self-igniting. Most fires in dry waste and compost sites are linked to the inadvertent addition of hot ashes, cigarettes, and other alight materials.
The internal generated heat in the HOTBIN will dry the contents to some extent, but once the temperature reaches 70-75°C, bacteria cannot survive and heat production is slowly reduced. The HOTBIN is designed to hot compost between 40-60°C, with air drawn in through the bottom and released as water vapor and carbon dioxide through the valve. The combination of damp waste, steam, and carbon dioxide significantly reduces the chance of combustion. The insulation properties of the material work both ways, keeping bacterial heat in and the sun’s heat out.
Can I heat a greenhouse with compost?
In order to heat a backyard greenhouse constructed from DIY materials, it is necessary to create a compost pile with a volume of one cubic yard for every 23 square feet of greenhouse space. This will result in an internal temperature increase of approximately 23°F to 35°F above the nighttime winter temperature outside. If the greenhouse setup allows, trenches should be dug in rows, filled with compost, and crops planted in the rows between them.
What to add to compost to make it heat up?
To maintain a hot pile, the addition of nitrogen-rich products, such as garden waste, coffee grounds, or grass clippings, or high carbon scraps, including shredded cardboard, sawdust, or straw mulch, may be beneficial if the compost is too hot.
How long does it take compost to heat up?
Once the compost pile has been constructed, it should be thoroughly watered and turned over, then left to sit for four days. Subsequently, it is advisable to ascertain whether the pile has undergone a rise in temperature.
📹 Heating Your Greenhouse with Compost: How to
In this video I show you clips of me creating a compost pile in the middle of a cold frame (hoop house) greenhouse.
This is a great idea, but two things that you would want to concider are its lifespan/lifecycle, and the gasses consumed and produced (may be dangerous?). To the first point, the pile will produce heat for a couple of months on average, but that’s probably enough for some areas to cover the colder winter months. The more important thing to consider is that a compost pile consumes oxygen, which could be bad in a confined space, but to compound that, if the compost pile IS in an oxygen deficient space, like the one it will create without good ventilation, it will start to produce potentially dangerous amounts of Methane and Nitrous Oxide, both of which are potentially hazardous to people and pets. So the problem I see with this is that you want to let the greenhouse breath, but you need to balance that with retaining the heat. I’m not claiming it can’t be done, or that it’s even difficult. It may just be that typical greenhouses allow enough air to come and go to keep that from being a problem. The plants may even be enough to turn the CO2 that the compost pile also produces into enough oxygen to solve the problem. I’m just saying it should be concidered, and I would be interested to see if someone has measured these things. Great idea, great website, great content. Thank you.
Today is a very warm winter day in Hungary but the real winter is coming and I have a small, 6.5m ×2.4m raised-bed, I want to upgrade it to a greenhouse this winter and I want to make a similar passive heating “system” like your. I have three questions: 1.) how cubic meter (or cubic feet, if it is easier for you 😉 ) was your pile? 2.) It is started to generate heat by itself or required to handle with any biological “starter” or compost or manure, etc… 2.) Is there any dangerous gases cumulated inside your greenhouse?! There is no any dangerous if the greenhouse rarely opened? Thanks for any answers.
Wow! I was thinking, perhaps with the warmth and the humidity it would be good for wintering potted tropical plants and fruit trees like lemons and oranges. What is your opinion on this? I found your website because of the cattle panel greenhouse and I already showed it to my husband for him to make one….. we’ll see. 😉
I had this idea in reverse recently: greenhouses, I’ve heard, can get warm in winter provided it’s sunny enough (although they’ll still chill off by night) – could I use the greenhouse to heat the compost pile, which would then heat the greenhouse, which would then help the compost pile stay warm? Or am I in cloud cuckoo land, as I often am?
I’m planning on building a 4×4 shaped above ground compost heater in the center of my greenhouse using pallets with wire mesh to contain it and disassemble when it’s time to move the soil to the garden. I have a $15 dollar laser thermometer so if I want to know the temperature anywhere in the compost I will pound a piece of rebar into the area I’m curious about, wait a few minutes, then pull it out and laze it. Hope it works!
Amazing share! Thank you. 👏We just built a Planta 32 x 10 foot greenhouse in zone 3/4, and would like to use this elegant method. I’m curious, does the heat produced warm the soil adjacent to the trough? I hear that soil temperature is more important than air temperature for plant growth, and would like to find a simple way of creating a radiant heat type floor throughout the greenhouse to prevent ground freeze.
Great article, one of the most useful and least annoying that I have watched. Query… 10 times as much dried stuff as green… 10 times the “volume” or the “weight”? I am assuming volume but thought I might ask.. Query 2. How long did this produce the 130F or so temps? For me freezing temps last from early to mid October until average last frost of May 15 so I am looking at 6 to 7 months of pretty decent freezing a year. The tube for oxygen is a good idea, though you might consider shorter vertical tubes within the compost pile to more effectively aerate, though as you point out you wanted to get a long term heat source rather have it burn out quickly. Also curious, could a person have any potential of “temperature control” over the mulch pile by controlling the “amount” of oxygen available via opening or closing off aeration tubes? For example you have x number of aeration tubes and are running at 150F, close off some tubes to decrease the rate of reaction and drop the temp to 130F, or on the converse running too low a temp and opening up air tubes to raise the temp. From what I have calculated you had 84 cubic feet of compost in a 1,000 cubic foot greenhouse with a single layer plastic cover. This heated up to 130F keeping the 1,000 cubic feet inside the greenhouse 20F to 25F warmer than ambient outside temp. I am assuming that likely the 20F above ambient is likely night time and the 25F above ambient is a daytime differential? Did you have any issues with too high of temps come March/April on warmer days?
Well done … very well explained, too, giving me inspiration to try this, or something like it, in my own hoophouse. Especially the mix of material for the pile … I take it that, some spring, you simply spread the pile out throughout your greenhouse for planting, or you didn’t touch it so to reuse/keep in “operation” this winter?
Exactly, in Holland farm factory, they pay money to inject CO2 for tomatos. This is it! I have one question, how long it would last to heat the greenhouse for that amount of piles. Also, the measurement of your greenhouse size, please to calculate the amount of compost needed to heat up the greenhouse how long.
How was the smell? Also, there’s some bacteria/mushroom. I don’t know about breathing it? Is it safe? Does someone know? I plan to surround at least 3 sides of the greenhouse with a compost pile but outside and tubes to flow water on the ground inside the greenhouse. I saw a man with 7 piles to heat 2 houses, the pig area, the chicken area, the greenhouse. Even the chicken pile also feeds them. No grains.just the pile of goody manure.
How wet should the compost be? Tried something like your idea, but without the manure. Woodchip mixed with leaves piled under existing greenhouse staging and held up at the sides by an air-porous barrier. Was very wet from rain when put in, became very hot for about 10 days then cooled even though re-watered a bit. Does anyone have experience of how much water to add to the rotting mixture and whether to re-water, if so how much and how often?
Nice build. I love the monster double wall hoop house. 😉 I also keep using partially buried piles, and I keep kicking myself. My current build (youtu.be/nR33FIFU3zY) has a partially buried compost chamber (though it is insulated with foam board, because it’s not inside the greenhouse). It’s really inconvenient to turn the pile, and unfortunately since my compost chamber is small, I have to turn the compost every two weeks. Done over again, I’d just have a big honking cube of compost, above ground. I’d be curious to see some more quantitative temperature data (intake vs outlet, outside vs outer hoop house vs inner hoop house.