The message
from Janet Tweedy contains these words:

Do I
a) buy a very large or even two electric propagators which are going to
set me back about £200 or

b) put in one of those large metal potting trays/stands then put in a
soil warming cable and fill with sharp sand and compost so I can strike
cuttings directly as I have been doing with two very large wooden boxes
up till now.

What does the team think? The greenhouse is an Alton cedar wood one.

Before the days when charity shops had to be fussy about accepting
electrical goods (in the mid '60s IIRC) I bought a double electric
blanket, sealed it between two sheets of polythene with a home-made
thing made from an old electric iron (same provenance) with a polished
bar of steel welded to the bottom of the plate.

I bought a same-sized sheet of expanded polystyerine and slabs of it for
the sides (from a packaging firm we did deliveries for) and dug a hole,
planted the polystyerine, placed the blanket on top, filled hole with
about eighteen inches of soil and compost and built a frame over it all.

With an old central heating thermostat to keep the temperature sensible
I had cucumbers and tomatoes starting there in February. The cucumbers
stayed there and the tomatoes were planted out.

That worked without problems and without electrocuting anybody until the
frame rotted away.

--
Rusty Hinge
horrid·squeak&zetnet·co·uk
http://www.users.zetnet.co.uk/hi-fi/tqt.htm