Non-industrial greenhouse coverings: what are the options?

First of all, it almost seems like any discussion of greenhouses here at permies needs to reference the epic greenhouse suck factor thread. Sometimes a greenhouse is not the solution to your gardening problem.

Nonetheless, I found myself musing this morning about hypothetical future times of food insecurity, which in my imagination are likely to coincide with periods of instability in the broader manufacturing and distribution systems upon which we tend to rely. (In less fancy terms: some shit has gone sufficiently wrong that the Walmart trucks don't roll no more.) It's in just such a time that I might decide I really do need a greenhouse to extend my growing season, help heat my house, protect my seedlings in the early spring, and so forth. But if I can't go shopping at Lowes for huge new sheets of plastic or chunks of flat new glass, what would I cover it with?

That got me brainstorming. What sorts of low-tech solutions exist for covering a greenhouse? Stuff that can be sourced or produced without petrochemicals or large manufactories? Products that can be made at a homestead scale?

Here's what I came up with:

1) Recycled/repurposed glass. Repurposed panes, bottles mortared together, glass bricks made from broken glass heated in a makeshift kiln.
2) Recycled/repurposed plastics too, but only for a few years without new-product inputs. None of that stuff has a long survival time when exposed to the elements.
3) With proper splitting/tanning/beating, are there ways to process hides/skins into sheets that are at once translucent enough and durable enough to survive a few seasons of use? Seems like durability issues would drive up the expense, because hides are rarely in huge surplus.
4) Isinglass (mica) sheets would be possible in theory, but you'd basically need a nearby mine to source enough.
5) New glass produced locally on a non-industrial scale. Bricks more likely than sheets, which are tricky to make.

What am I missing? It's not an easy problem.

Any habitat for humanity restore should have a dozen or more sliding glass door panels for cheap. They are being replaced with French doors and plenty to be had.

I got some that are 4 ft wide (free) from a contact. Solar water heater, cold box, many spplications. I even used it to solarize (kill weeds) in certain areas.

Alternates to a greenhouse might be something like a cold-frame, without glazing, which is covered with a blanket if temperatures are expected to be too low for the plants. Especially if the cold-frame was sited to take advantage of warmer micro-climates.

Hey Dan,

When I read the title of this thread, I was thinking the zombie apocalypse scenario and there is no industry left functioning and everyone is Mad Max'in it up. Ha ha. Funny how the brain goes off on it's own and makes things up. but seriously, if the ca ca really hit the oscillator...

It's in just such a time that I might decide I really do need a greenhouse to extend my growing season, help heat my house, protect my seedlings in the early spring, and so forth. But if I can't go shopping at Lowes for huge new sheets of plastic or chunks of flat new glass, what would I cover it with?

I like the idea of bottles mortared together. There are millions of excess bottles and jars laying about. It seems like making glass bricks would be a lot of extra work.

In the absence of mortar (i usually think concrete when i see the word mortar, and concrete is pretty industrial and hard to make from scratch), one could use cob. I could also imagine building a post and beam frame and having the "glazing" built of even sized bottles (which could be plastic for a while, or glass for a long time) that are stacked tight and then with a chinking of moss added afterward, which could be quite insulative as well. If these could not be built up as full sized walls because of stability issues, smaller frames could be made and then these could be inset into a larger frame.

I also like Joseph's coldframe.

Of course, as you and Wayne came up with, re-purposing old glass is always an option. or is it? If the industrial world collapsed (rather than just being something out there that we are choosing not to use), then re-purposed glass would not be cheaply available for long. Even if times got tougher, the glass would not be readily available.

I doubt hides would work long enough to be worthwhile, considering the calories spent to tan the hides. They tend not to like moisture, from my experience.

When I first read the title of the post, what immediately came to mind (after the zombie apocalypse!), was mica, but that is some endeavor. I actually do have an old mica mine somewhere near me, way up a mountain, but it's still a serious project, I would think.

Here's the best I can come up with for a homestead based post industrial greenhouse-ish structure:
In the absence of any glazing available at all one could take the cold-frame and micro-climate idea a step further and build a solarium type structure with hugulkultur beds, a large vermi-compost, and a rocket stove mass heater and plenty of extra thermal mass (stone/cob) inside. A blanket or three (or hides with hair on) could be hung from the top of the frame to close in the space to hold in heat. Pretty much a cave man greenhouse!

I think crater gardens with kids of large stones and maybe a pond will help extend the growing season, especially when coupled with blankets for cold cold weather.

I'm hoping to have a walipini in before the fecal matter hits the wind turbine.

When it does, there will be a bonanza of scavenging, I think, for those who are left. The ReStore is petty great for now, and yardsales can yield good old windows. We have done great big sheets of Plexiglass from old light-up store signs.

Even in a moderate economic collapse /peak oil scenario, I imagine sky scrapers will be abandoned due to the inability to heat, cool, and access them. (Hauling water up 60 flights of steps with a bucket, anyone? Or hauling anything else? And the building is basically a giant greenhouse without the thermal mass. Add in the chimney effect and it will be unlivable.)

So, urban cores will be "glass quarries" for quite a while, I imagine.

I have a vision of a skeleton forest of skyscrapers looming over a town of retrofitted buildings, each with solar heaters, greenhouses, etc. built from their glass.

Much the same way as the huge masonry structures of Rome or Egypt became stone quarries in the medieval period.

My last post didn't really answer the question, though.

I have done some research on cottage scale bioplastics, and that might be viable. I think they would crumble after one season, but it might work.

Some sort of waxed or oiled paper might work too.

Also, I used a glass less brick frame to raise tomato seedlings here in Colorado. I started a whole bunch of little seedlings in dim light on heat mats inside. A rocket bench would be wonderful. Then, once they sprouted, I moved them into a very crowded glazed frame for another few weeks. By this point it was April. Night were still cold, but daytime temps, especially with the brick walls, were not bad. Every night I put a big sheet of styrofoam insulation over them. I can imagine lots of other things besides styrofoam being used.

This set up probably made the plants a lot easier to harden off. I had to do this because I raised 500 tomato seedlings, and 500 pepper and eggplant seedlings for my farm.

I thing an old refrigerator or freezer would work really well this way. Leave the lid up during the day to let sun in, shut the lid at night. They are insulating and have reflective interiors, and would last a long time after everything fell apart. The bottom might have to be filled with dirt to reduce the depth and let sun in.

If you try this, take the latch off so kids don't get trapped.

Lots of thoughtful answers to a difficult question that probably doesn't have a great answer. AFAIK there weren't any greenhouses until industrial sheet glass became available.

Gilbert Fritz wrote:
Some sort of waxed or oiled paper might work too.

I really like this notion. It's hard to imagine how to make it both thin and durable enough without industrial presses, bleaches, and finishes; but just because I don't know how to do it doesn't mean it couldn't be done.

Gilbert Fritz wrote:I thing an old refrigerator or freezer would work really well this way. Leave the lid up during the day to let sun in, shut the lid at night. They are insulating and have reflective interiors, and would last a long time after everything fell apart.

I am trying this experimentally with a huge defunct chest freezer this winter, which I am using to overwinter a variety of tender tree seedlings in small pots. Last winter I had substantial losses among my potted tree seedlings, especially the ones that got going late in the season and weren't large or robust by fall. This summer I scrounged some five gallon plastic cooking oil jugs, which I put in the bottom of the chest freezer full of water to serve as a thermal mass. I stacked the pots on top of them and have (so far) left the lid up facing the sun. If we get "cold weather" (which in local terms means temps in the teens, coldest I've seen here yet is 12 degrees Farenheit) I figure I'll just close the lid at night.

About the waxed paper, the issue would probably be how translucent it would have to be.

I wonder how much light a layer of rather dirty greenhouse plastic, and another layer of spun bond row cover cuts out? That's what Eliot Coleman uses.

So a sheet of waxed paper might not actually cut out too much.

I might just try this out next year, if I get the time.

I saw some glassine bags for sale in a seed catalog, and was moved to look it up on Wikipedia. Glassine is a type of highly translucent and moisture-resistant paper that was made as early as 1836, but the supercalendaring machine they use to make it looks pretty seriously industrial, drat it!

I was googling kelp paper and saw some that seemed rather translucent.
Blankets seem way to valuable to waste in a scenario like this.
Horn windows are doable.
Any material that is water susceptible could be protected by large overhanging eaves, winter sun being rather low in the sky.

A loosly woven shallow basket could be smeared with material that is translucent but too weak to be a sheet on its own.
Imagine a sieve clogged with a translucent or gel.
Some candidate's for this include beeswax, lanolin, candelilla wax, bayberry wax, gelatine, hide glue, linseed oil,  rosin, isenglas and rice glue.
These are all potentially produced in colder environments.

Fish leather could be an answer to the scarcity of hides, it also has water resistant and translucent properties.


Being able to make paper , glue and waxes seems like all around useful things that can be pressed into creating windows.

Being able to make the simplest translucent glass seems very useful as well.

I understand that this is more an intellectual exercise than anything, but I simply can't foresee any sort of situation where glass won't be available.  Sliding glass doors are always available.  Large glass companies give away sheets of tempered glass in pretty much any size or thickness you can think of.  In a true grid down situation that lasted an extended period of time, there will be a lot of houses and buildings that have windows available.  I think it would be a long time until existing rolls of plastic would be used up.  Hopefully all these things will be available for any foreseeable future.

The idea of using small piece of glass or of glass block took me back to an idea I had,  a "stair roofed building"
The risers of the building would be closed in with strips of glazing, while the stringer/tread area could be a green roof or something else.

Some deeper searching turned up this:


https://www.archdaily.com/84612/stair-house-ymdo

The article notes that the set up blocks direct summer sun from entering while winter sun enters more directly.
It occurs to me that any plants sitting on such a roof would benefit from relatively warm roots.

In our post abundance scenario, bottles walls could be the risers.
It would be like a series of clestrorys, each higher than the next.

Erica went deep into this subject here:

https://permies.com/t/55045/Medieval-windows-horns#458996

The whole thread applies,  but her post stood out!

Two thoughts I have are:
Look how good we have it, that we don't need to recreate medieval horn window manufacture just to grow food for ourselves. There's abundant materials that are much easier to implement, many can be had for cheap or free.

Hoarding seems like not so bad an idea. Wait. Let's call it "seizing opportunities" when free or cheap materials are available, planning for a time when they may not be any of those. That may also be the time available by necessity to transform it all into something...
*not an auto-biography* (I swear) ;-p

Rawhide, scraped very thin, was used as rough windows in remote cabins where sheet glass or even glass bottles were impossible to get. I doubt this would transmit enough light for plants on a consistent basis. But if there is excess zombie skin available, well ...