Greenhouse glazing: glass or plastic twin-wall sheets?

May 25, 2023 – 03:57 am

While traditional greenhouses were covered with glass now offer plastic twin-wall sheets in some areas better properties. I'm in this article exclusively on a rigid glass. About Greenhouse films and their various materials you can inform yourself here.

The nature of the glass affects the plant growth by the degree of light transmittance, ultraviolet transmittance and insulation. The ideal glazing allows visible light and UV radiation and block heat radiation. Furthermore, it has as few gaps through which air can flow, and is insulated from heat conduction and radiation.

Good insulation prevents the greenhouse during the summer is extremely hot and burn the plants. It also helps to keep the heat inside in winter and so to save on heating costs.

Light in general is the fuel for plants and should therefore arrive as intensively as possible through the plates. UV light in particular promote the growth path as well as certain maturity processes. The lack of UV radiation leads to the typical bland tomato glasshouse taste. Basically, grow, bloom and bear fruit plants but also at low UV light intensity.

Glass

Glass is the traditional material for roofing and still has some advantages over plastic. It is extremely durable and weather resistant, so that even after decades of good light permeability is given. With a light transmittance 89-92% it is superior plastics.

Disadvantages are the breakage of glass, and the low transmittance with respect to UV radiation.

It is between bare glass, which is completely transparent, and clear glass (horticultural cast glass), which is patterned on one side, so that the light is scattered. Previously suspected that the higher dispersion of plants prevents burns. However neure studies show that this effect is negligible, so that it can be decided here by price and appearance. In order to ensure sufficient mechanical stability should force actions against the glass thickness of at least 3 mm.

For heated greenhouses insulating glass should be used. This consists of two panes of glass with a gap, which is often filled with carbon dioxide. The isolation level corresponds to the double-skin sheets of plastic, but the insulation is much more difficult. Insulating glass is therefore mostly used due to its weight and the associated demands on the supporting structure only for complex, large greenhouses.

Plastic - double wall sheets

16 mm twin-wall polycarbonate sheet. At the hardware store, the plate costs 40 € / sqm.

For small private greenhouses are set to increase by plastic roofing. Here, panels are polycarbonate ("Makrolon") and Plexiglas ("acrylic", PMAA ) proved to be most suitable. They consist of several individual plates used washers which include a layer of air for insulation. One speaks of hollow panels and double wall sheets. These are available in thicknesses from 4 mm to 16 mm - the higher the thickness, the better the insulation effect. For a heated greenhouse in Germany a minimum thickness of 6 mm is recommended.

For a small private greenhouse for growing vegetables are recommended UV-transparent Plexiglas double-skin sheets - if there is a risk impact polycarbonate twin-wall sheets.

Plexiglas ("acrylic", PMAA - polymethyl methacrylate)

Plexiglass is available with significantly different material properties. Acrylic glass for greenhouses is the plastic with the highest light transmission - it is at 16 mm twin-wall sheets high 86%, which comes close to glass.

Source: kleinesgewaechshaus.de

My ex and I had no wine glasses when we married

2010-08-23 18:07:49 by -

Funny how on our 1st aniv we got like 6 sets of wine glasses???
We used to use cheap plastic cups that first year which was nice, like incognito we'd walk around in love, boozin on red wine in public in our big gulp cups.
Years later now, like 20 years later i am dating a woman whom I have to set out the right kind of wine glass or I'll be told to correct it as we can't misuse the improper wine glass for the wrong wine?
~She is anal but every now and then lets me stick it in her anal cavity :)~

Ten cool Father's Day gifts  — Sydney Morning Herald
Keep track of all that plonk with the uber cool series of wine journals from Moleskine.

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