"Douglas" wrote in message
...
Addendum
**************

I wrote all that stuff and forgot to explain "why the raised beds"?..
Quite simply you get more success with raised beds because there is a
bigger mass of compost in them (more volume) then the normal ground level
method, and this is because the greenhouse warm air during the day heats
up
to that mass temp and the mass retains the heat for some considerable time
during the night. A small portion of the heat is dispersed into the
inside
air of the greenhouse, enveloping the leafage, - but best of all the level
of heat is prolonged in the raised bed and the roots get the best of
continued warmth for a longer time when the temperature outside has
dropped
considerably.
Doug.
*************

oh right, kinda like soil warming but without the wires.