Hi, Keith.

I follow the same regimen as you - set the thermostat for the minimum and
let good old "Sol" do the rest of the heating.

Many years ago, I did have the thermostat set to raise the daytime
temperature, and the result was plants that would get leggy and weak.

I know that warmer temperatures lead to faster growth, and that in winter,
we don't have sufficient light intensity to go along with that growth, but I
cannot claim to know the mechanism.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies. Books, Artwork, and lots of Free Info!


"keith kent" wrote in message
...
In my greenhouse (3 1/2 years) i have always relied on natural solar heat
gain ,i kept the greenhouse heater set at approx 60 f and let the sun do
the rest.Obviously there are times when there is no heat gain for a few
days ,but havent seen a adverse affect with this ,although more careful
watering/spraying is needed.I have had good flowering too,i am now keeping
the greenhouse at 50f as i am now going cool so the temp difference should
be easier to achieve.At this time of year in the UK on sunny clear days
the temps rise to approx 60f in the greenhouse.All the books state the
heaters need to be set for a daily temp difference and other growers i
know do without fail .I havent had any problems to warrant me to
unaturally set the daily temp higher.
What do others do and what experiences have you had with either way of
trying to achieve the temp diff.
By the way my reason for not raising the temps other than solar is
financial and it does`nt seem natural to raise temps if the sun light is
not there.
Any others with pro`s and con`s with first hand experience will be an
interesting read ..

Thanks Keith