When thinking about what to enclose your greenhouse with, be mindful
that there are many different coverings to consider. Glass, Fiberglass
panels and Double-Layer Structured panels are all effective glazings,
each with its own advantages and disadvantages.
Glass
Glass is one of the more traditional greenhouse coverings and also the
standard by which all other coverings are judged. Glass is an
attractive and formal greenhouse covering. It is also very transparent,
allowing your plants open access to direct sunlight. Glass paneling is
strong, but can become brittle with age and is subject to shattering.
Also, because it is heavier than other materials glass requires a more
robust framing support than other covering materials.
Fiberglass Reinforced Panels
Fiberglass reinforced panels are rigid plastic panels made from acrylic
or polycarbonate and come in large, corrugated or flat sheets.
Fiberglass panels are available in 24 to 57 inch widths and up to 24
foot lengths. They are durable, a better insulator than glass and are
lightweight, requiring less structural support. Large panels are
flexible enough to be applied to less traditionally shaped greenhouses.
Light transmission may be better than glass simply because less
structural support is needed, which creates less shadow. Inexpensive
materials may be guaranteed for as little as 5 years; more expensive
types may be guaranteed for as long as 20 years.
Double-Layer Structured Panel
On of the most popular and functional greenhouse coverings,
polycarbonate, double-layer structured panels are made of two layers of
plastic held apart by ribs spaced 1/2 to 1 inch apart. They are
lightweight and can be easily shaped to fit most frames. The
double-layer construction increases structural strength and heat
retention but decreases light transmission compared to single-layer
materials. Most provide a diffused lighting that is beneficial to most
plants. Panels are 4 feet wide and up to 39 feet long. Most are UV
resistant and carry warranties from 5 to 10 years against yellowing.
