Thanks Peter, I will try the relatively cheap fan it is & see how I get on (weather forecast says 3 degrees tonight; first widespread air frost of the season according to the weatherman).
Jim, the soil warming cable is very interesting, I had never thought of that. It appeals because it must get the warmth right to the plants before warming the air in the greenhouse. The plants which require more warmth (succulents such as gasteria) can be positioned closer to the cables. Presumably you lay your cable on top of the staging on two sides of your greenhouse? How long is your cable? If my maths are correct 24m of cable would go round three sides of staging staging on a 8 x 6 greenhouse three times.
Stick to the fan heater Brian.....much simpler and as others have advised it keeps the air moving which is beneficial.
You really need to research what your plants need. 3C isn't that cold if you grow certain cacti & succulents......but it could be fatal for others. For my plants I don't even think about turning on the heating until they forecast just above freezing.
Gasteria need heat? Not true. Mostly as long as they don't freeze they'll be fine.
What exactly are you growing? Unless you've filled your 8x6 since the spring you must have heated last winter? Paraffin or something? Let us know and we might be able to advise better.
Chris Rodgerson- Sheffield UK BCSS 27098
See www.conophytum.com for ca.4000 photos and growing info on Conophytum, Crassula & Adromischus.
Brian wrote:
Jim, the soil warming cable is very interesting, I had never thought of that. It appeals because it must get the warmth right to the plants before warming the air in the greenhouse. The plants which require more warmth (succulents such as gasteria) can be positioned closer to the cables. Presumably you lay your cable on top of the staging on two sides of your greenhouse? How long is your cable? If my maths are correct 24m of cable would go round three sides of staging staging on a 8 x 6 greenhouse three times.
While the "normal" use for this cable is buried in sand/gravel benches with plants either plunged or on top this would have made for a heavy/expensive setup for me so I took the simpler option of just using the cables under the 3 levels of the staging in my greenhouse which is 8 foot wide and 6 long and the cable is under the 3 levels of the staging that runs along one side and right across the back end (so approx 2 foot into the other side) It is so long since I did the installation that I cannot remember how long the cable is - might try and do a rough measure tomorrow to see how the up/down runs are arranged as the thermostat is on the middle staging to one side of the fan on the opposite side. If I was doing it now I would probably just put some tube heaters under the bottom of staging which I am sure is a simpler installation if you already have plants in the greenhouse - I installed the cable in a new greenhouse which made it fairly easy to handle the long loop of cable which cannot be cut.
