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Karyn Schoem


Thanks so much for this! Great research, visuals!

Nils Hjelte


Thank you



As usual, you have posted another important and thought provoking article of extraordinary high quality. Kudos to you!

Have you considered crowdfunding this website via, say, Kickstarter.com or Patreon.com so that you would have time to write more frequently? Also, have you considered focusing on obtaining guest posts on this website? In other words, instead of focusing on writing, if you were to focus on editing you might be able to leverage your talent for ferreting out valuable solutions to provide more extraordinarily high quality content for this website.

In addition, I hope you might consider a follow-on piece about rammed earth dwellings. They are like kissing cousins of the Chinese greenhouses discussed in this article. You might think of a rammed earth dwelling as being very something similar to the Chinese greenhouses. Except instead of being designed for plants to live in, rammed earth dwellings are designed for people to live in.

Here are a couple of links on the subject:

Builder Sylvia Cook Sharing Insights on building with Rammed Earth

In rural Ontario, a high-tech home built of low-tech dirt

If you want some more links to rammed earth articles and videos please let me know by responding to this comment.

Sherwood Botsford


Heating with compost/manure

Some care has to be taken to keep the C:N ratio over 30. If there is too much N, then the decomposition releases ammonia, which as a gas is tough on the plants, as well as your sinuses.

That said: For the amount of CO2 needed, a rather small gas flame would suffice. While not completely solar, this would still be a large step forward.

In addition, this would be a viable backup for compost heating. If no natural gas line is available, propane is a somewhat more expensive, but more portable alternative.

Teng Yang


Interesting article! I always wondered how modern greenhouses got their start.

Question, would putting large space blankets over the greenhouse at night, much in the way the Chinese used straw mats, help to retain the heat better at night in an all-glass greenhouse?

To borrow again from the Chinese design, would adding a second glass structure just slightly above the greenhouse to help trap the heat better, especially if combined with the space blanket design?

I suppose it would take up more space and require more resources such as more glass, but would it be cost-effective enough in reducing the need to heat the greenhouse?

Ting Henson


In cold but sunny climates like the Manitoba test, would a beer / pop can furnace be sensible. coupled with a small solar powered / switched circulating fan and using raised beds to increase the solar mass.
Just a thought.



hemp works great...


Bo Robert Atkinson


Thanks and here is my concept-




For a moe low-tech CO2-source than the modern gas burner, why not put in a small wood stove (or even those DIY things you build from cans and feed with sticks that were designed for cheap and fuel-conserving cooking in developing countries), or the old charcoal brazier that kept Roman tents warm on military campaign?

Or a nice old oil lamp with storm-safety features, filled with plant oil instead of kerosene. The point isn't efficient light, after all, just the burning. Hell, even a few of those covered storm candles that Catholics put on graves and leave alone would probably be enough.



This principle of rolling blinds can be used to conserve living space heating and cooling, too. But remember that it is important to install the blinds on the outside of the window, especially to keep out the heat in the summer.

Where I come from, many houses have rolling blinds made of wood, metal or plastic, about a handspan outside the actual window, so they are flush with the wall. More expensive setups are even automatic and timed or they have sunlight sensors and go down when the sun sets and up when it rises.

These blinds don't just help keep the house pleasantly cool in summer (nobody here uses air conditioning), and discourage break-ins (the timed blinds are mainly to make it look like someone's still in the house when you're on vacation; and it's just not that easy to open a window from the outside if there's a sheet of metal or heavy wood infront of it), but put down on winter nights, they help a lot to keep heating costs down, even if the windows are already double- or tripple-glazed. Indoor shades or even thick black-out curtains dont help nearly as much.

Also, is there a particular reason (other than price at large scale) why the Chinese aren't using bubblewrap foil or similar instead of plain single-layer PVC? Is it a light refraction issue or something like that? Or would it get too hot in the summer? 'Cause I've taped a double layer of simple packaging bubblewrap into some attic windows that don't have outside blinds and which tended to condense air moisture on the inside when it's freezing outside, despite being double-glazed.

The bubblewrap stopped that, helped the room retain heat better at night (when the central heating is switching itself off because the rest of the house doesn't lose much heat), and it doesn't significantly darken the room, so I just leave it on all year now. (The brown roof tiles and wooden construction of the roof mean I always had to keep the windows open 24/7 in the summer anyway, to keep the room below 35°C most of the time.

Wood framing and a foot of fiberglass insulation can just never be as good as proper brick walls, which together with the aformentioned heavy blinds, keep the rest of the house below 25°C.)

I mean, even if bubblewrap really is too costly for large commercial operations, for small homesteading greenhouses, a transparent insulating blanket that you can just leave on all winter instead of having to roll it up and down every day - even when it's wet, covered in snow, or frozen to the main plastic sheet with a layer of ice - sounds more practical.

The little free-standing, unheated garden greenhouses that I see in alotment gardens sometimes are also made of some sort of double-layered transparent plastic with an air space between (hard plastic panes, not foil), instead of more expensive and fragile glass. (These greenhouses are mainly used to give cucumbers and such the few extra degrees they need to grow in our lattitude, even in summer, and to keep tomatoes from dying of brown rot for another few weeks after the rains start in early September. They're not meant to actually grow anything wildly out of season, and they're not frost-free.)

Though after a couple of years, they take on a green sheen - I assume there's algae growing between the two layers - and that reduces the light that reaches the inside. So that's not ideal either. Well, maybe if you take the extra time and a tube of window putty / bathroom silicone sealant to make these prefabricated plastic panes properly watertight from the start. Still, plastic foil, and even bubble wrap, is a lot cheaper.

Erik Andrus


Very cool concept, I have been thinking along similar lines for a greenhouse on my farm. I have to take issue with one minor point made, though:

"A passive greenhouse industry would thus take up two to three times as much space to produce the same amount of food. This could be viewed as a problem, but of course what really eats space in agriculture is meat production. A more diverse and attractive supply of vegetables and fruits could make it more viable to reduce meat consumption, so land use shouldn't be a problem."

This isn't really how land use decisions are made in agriculture. It is much more related to supply and demand, and whether investments in infrastructure can be justified with a rapid payoff. For instance, if a conventional greenhouse pays for itself more quickly, almost all growers will have to go that route just to survive economically, pay taxes and loans and so on. I agree it would be good for a sustainable society to have a wider variety of fruits and vegetables grown with a low energy cost, but most farmers have to take their cues from their markets, rather than the other way around.

For instance I'd like to put in a large greenhouse along these lines to grow rice seedlings in spring and other stuff the rest of the year. But the building materials are expensive, and the food competition for anything I might produce for market, shipped from thousands of miles away to my local grocery store remains cheap. Once food in general becomes more expensive we'll likely see a lot more of this kind of creativity on small farms.



Hello. Thank you for the great article. Is composting not a viable option for CO2 production (and heating) inside a greenhouse?



I know I'm late to the party here, but what accounts for the production drop off in passively heated greenhouses compared to full glass? Is it less sunlight?

kris de decker


@ Evan,

Yes, it's less sunlight

@ Andre

Yes, you can: the last part of the article is devoted to compost heating.




J in China


@ Evan @ Andre,

I think it's worth pointing out here that the reason the light is reduced in this kind of greenhouse is that there are opaque walls on the north and half walls on the east and west sides of the structure, reducing the light in the early morning and late afternoons, as well as severely restricting the light in the height of the summer. Basically these greenhouses are only productive in the wintertime. A solution to this would be to build permanent walls to only half their height and using removable pieces for the top halves, allowing you to remove the obstruction when the sun is in the north. I've been talking to a couple farmers here in China about exactly that this winter (I live an hour south of Shenyang, the city mentioned in the story) and I think large papercrete blocks could be a good compromise between mobility and insulative properties.



I read "CO2-source" + "Thermal capacity can be further improved by placing black painted water storage tanks"

...and I immediately think of brewing and aquaculture. I'd rather share an enclosed space with these than with a dung heap.

1) grow carob on more marginal (rocky / hilly / dry) land, and ferment the pods (which store and transport well) in the greenhouses. Do distillation through winter, when the waste heat would benefit the greenhouse.

2) raise fish / snails / crayfish, such as the common yabby (Cherax destructor), which eat algae and dead plant remains. This would turn some of your cucumber and tomato leaves back into CO2 + tasty flesh.



Well, I don't know a thing about agriculture... But, what about using fluorescent/UV lamps?

I remember watching a video that showed how a solar water heater worker even in cold climates. Could you use hot water to heat the soil and, with that, the whole greenhouse?

Aquaponics sounds like a better idea, though...



What about to use biochar for heating the soil and to increase heating of bricks?



Just found this from 1818 garden magazin https://flic.kr/p/HrPmow



No tech reader 18 http://www.notechmagazine.com/2018/03/no-tech-reader-18.html has a link about the great nutrient collapse https://www.politico.com/agenda/story/2017/09/13/food-nutrients-carbon-dioxide-000511.
this article makes reference to increasing the co2 level without mentioning that may be a bad thing.
Maybe an addendum is called for to point out that increasing co2 in your greenhouse may not be best?



https://en.wikipedia.org/wiki/Eliot_Coleman has researched and written books about passive solar greenhouses. https://en.wikipedia.org/wiki/French_intensive_gardening and https://www.chelseagreen.com/2012/history-of-winter-gardening-the-17th-century-french-garden-system before that used compost, glass enclosures and insulation to extend the season.

The Chinese greenhouses are in line with what works for farmers, not just armchair gardners.

I like the idea of including animals in the mix. Chickens can help with pests as well as provide manure and disposing of some plant waste.

One issue with stand alone, static enclosures is the build up of salts and pests in the soils. Periodically exposing everything by removing the covering or moving the structure alleviates this. Perhaps some kind of movable thermal mass with movable insulated structure for the back wall could facilitate that.



Tom, I like the movable idea, or possibly better yet, space permitting, build the same thermal mass structure side by side and move the "glazing" structure every couple of years? Heck you could even leave in the "ribs" of the greenhouse and just change the glazing...

Matt in Oklahoma


Very good article

Dave Bross


here's a good one, with tech specs and some how-to:


there are also videos on Youtube of people touring this. Search under citrus in the snow.



Geothermal heating allows very little energy use, just a heat pump. The most northerly greenhouses, dig a hole 3-6 meters down, its got a temp of 10-13° C.



It would be much more interesting to compare the amount of veggies being harvested in relation to the amount of embodied and spent energy over time and calculate on the net energy, EROI. Not just compare an extensive alternative with an intensiv system. And in this context profit also should refer to something that is sustainable and also lasting and doable in a postindustrial world.



I live on 60 ° N (Stockholm / Sweden) = not enough sun okt-feb. Do I then really need to consider the southern part being perpendicular to the sun's rays when it's lowest on the horizon. That is 8 ° lunchtime in dec ... That would be an angle of 82 ° right? I might instead build from which the angle of the sun is at lunchtime in okt, since the veggies can't photosynthesize after that?

Aubrey Zhang


This Chinese style passive solar greenhouse can be improved further by incorporating a double layer structure that to be filled not with air but soap liquid bubbles. We have demonstrated that its performance can be boosted to a much higher level that is simply amazing. See here for more info: pyrapod.com/problems-with-traditional-greenhouses-how-to-retrofit-with-solaroof - I made a video showing all the results. As for the north wall, the infrared imaging shows that it does not need to be opaque and built with fixed thermal mass. The geo thermal effect is more prominent in the ground rather than in the north wall. Replacing the opage north wall with transparent double layer cavity and filling the cavity with soap liquid bubbles is the best way to increase solar thermal energy intake without sacrificing the light intake.

Jason in Canada


I read this low tech magazine article a while back and today I saw a video showing a person from Alberta, Canada using a Chinese solar greenhouse. I thought it might be of interest for people to see a Canadian example in 2021.

Growing year round in a passive solar greenhouse without heating

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