Organic greenhouse coverings

I've been thinking about greenhouse coverings. It just seems like there has to be a better, more sustainable and hopefully cheaper way to cover them than plastic, fiberglass, and glass.

It seems that current methods have borrowed heavily from window material and to a lesser extent from roofing materials. A greenhouses needs are somewhat different given that it doesn't have to be transparent, only translucent or even just have a way to reflect light into a closed structure.

What about oil cloth or paper, a solar collector and reflector system that "pipes" light into an insulated building or basement, a covering that only allows the passage of, say 50% of available light, but has a reflector shining on it to make up the difference?

Interesting notion!

I could imagine a parabolic trough collector that focuses sunlight through a very narrow opening in an insulated structure, and onto a diffuser (illustrated crudely below). Having the diffuser being a dependable location for strong light might match well with techniques developed around grow lights.

There are also lower-cost trough collectors built of flat mirrors, that are angled based on their distance from the center of the collector.

I don't know precisely how the cost, durability, and environmental impact of reflective optics (i.e., mirrors) compare with transmissive optics (i.e., windows) at the low end, but it is usually nice to have options. It's definitely an idea worth exploring.

lhtown,
you really ought to try out some oil paper or oil cloth as a greenhouse covering and report on your results.  maybe just a small greenhouse to begin with.  should be really affordable to do and you could be on to a great idea.

I've seen folks use oiled paper for windows, so I think it could work.  two layers separated by a dead air space should insulate fairly well, too.  please give it a try.

I'm not in a position to try the oil cloth yet, but maybe this fall, I will be able to experiment a bit. For anyone interested, here is a link to someone who used oil to waterproof linen:
http://www.fullchisel.com/blog/?p=781

Is anyone aware of any historical instances of using oilcloth/paper for a greenhouse?

It would have the distinct advantage that you could potentially produce it locally or even on site. I suspect that the light would be greatly reduced as well as any solar heating.

The bacteria in kombucha produce an exceptional paper.

The cellulose fibers are not only finer than a plant cell, they're finer than a bacterium; no eukaryote cell wall can compete with that! Each fiber is also much longer than an individual cell (they extend outside the bacterium).

Fairly thick paper of this sort competes with Kevlar etc. in the market for high-end speaker cones. I imagine a thinner paper would be excellent in a greenhouse; for one thing, each fiber is much smaller than a wavelength of visible light, and so waxed/oiled paper that is uniform enough would be entirely transparent.

One important development would be to find a recipe that keeps a SCOBY alive without adding tannins.

Kombucha paper..
Wow.

Do you have any links to real life examples of this sort of paper Joel?
I would be veeery interested to find out a little more.

Here is a link to an article about clothing material grown from bacteria in the UK. Perhaps a similar thing could be made into a greenhouse covering...
www.ecouterre.com/20103/u-k-designer-grows-an-entire-wardrobe-from-tea-fermenting-bacteria/

The only info I can find on the use of Kombucha type fibers to make paper is this:
Google "Paper  - Biopaper obtained from microorganisms" (it's a Word .doc)
It seems as though the paper would be very moisture absorptive, so probably not the greatest for covering a greenhouse.
Anybody else got any ideas?

http://www.stumbleupon.com/su/1TSCnq/inhabitat.com/2008/09/24/jasmine-zimmerman-bottle-house-at-bumbershoot//r:f

Interesting greenhouse idea using recycled bottles.

The greatest majority of heat and sunlight enters a greenhouse from the south.  The north side will have some gain from reflected light, but the heat loss at night will far exceed any gains in the daytime.  Practicality and simplicity are the reasons behind hoops with a clear covering on every exterior surface.   A design with a solid north wall would decrease the solar gain by a small amount while improving insulation and heat retention dramatically.  Cut the surface area of the covering in half, the project gets a whole lot easier.

Connecting a greenhouse to the south wall of an existing structure makes good sense.  Less construction time, fewer materials, and the benefit of heating that structure.  Whats more, during especially cool nights the heating systems in the structure can be used to keep the greenhouse comfortable without installing more heaters/ducting/burners/radiators/systems. 

For covering, I prefer glass.  As long as I don't get too carried away with the weed wacker, glass will last indefinately.  There is plenty of glass sitting around in sheds and basements that I don't have to buy new glass. 

The reflectors are an interesting idea to ponder.  In effect, you would be building a solar oven on a grand scale.  Looking at some solar oven designs may offer some insight for designing a reflector greenhouse.  A pond on the south side of the greenhouse would make a fine reflector.

Rob Alexander wrote:
It seems as though the paper would be very moisture absorptive

Yes, I meant to suggest using a drying oil to waterproof the paper and to make it transparent. Once it has absorbed oil, and that oil has cured, it won't tend to absorb moisture.