On Fri, 6 Dec 2002 16:59:55 -0000, "MC Emily"
wrote:

"Rodger Whitlock" wrote

Turning to your specific situation, if you think that sowing seed
of hardy plants (not necessarily cowslips) might become a regular
event in your life, then maybe it's time to cobble together a
coldframe.

OK, I'm interested in doing this but can I use clear perspex rather than
glass, for safety's sake? I have to admit to not liking glass at all, after
having an accident some years ago with a glass tumbler. I even have my wine
out of a perspex 'glass' now!!

Any transparent polymer will do. For that matter, a simple wooden
frame with polythene sheet stretched over it will do quite nicely
as a coldframe cover. There are technical reasons for glass
having a slight edge in this use -- better light transmission,
won't yellow or go cloudy or turn brittle[1] with age, won't get
all scratched up, perhaps a little easier to keep clean -- but
these are not important enough to preclude the use of a plastic.

A few other tips on coldframe construction:

1. If you can put it on a concrete surface, so much the better.
Helps keep worms from getting into the pots and provides fewer
hiding places for creepy-crawlies.

2. Make sure the frame and its cover are well tied down so they
don't blow away in a winter gale. I've had a coldframe cover 4.5'
square blown off in a gale -- and it was glazed with glass, but
fortunately it landed in a fuchsia that cushioned the landing, so
there was no breakage. Big heavy thing, but whoosh! there it went
in a powerful gust.

3. Don't make the frame any deeper than absolutely necessary.

4. If possible make some provision for hosing off the surface it
stands on, at least once a year. Potted plants give off a lot of
silt in the water that drains through them, and this can, over
time, build up to a thick layer of mud.



[1] Though old glass seems to be more brittle than new glass.
--
Rodger Whitlock
Victoria, British Columbia, Canada