new green house - what heater?

[Allan]

Most plants survive at surprisingly low temperatures above as long as there is bottom heat so invest in a soil heating cable with thermostat and just put a cover over the top.To heat the air only is waste of money and could kill some plants.
I got my large setup from CMS gardening, quite well made but I modified the thermostat by putting a neon inside to tell me when it switches on. The cover is 1" timber frame with bubble sheet.
Allan

[Colin_M]

I don't think I've seen anyone suggest paraffin-type heaters so far.

Are these now thought to be not as good, too expensive or a source of problems? I guess one issue is that they can produce moisture which might lead to condensation etc.

Any other reasons why we shouldn't use them?


Colin

[Allan]

Paraffin will need a considerable amount of attention and I have never known it thermostatically controlled, also it makes a lot of water as it burns which could be troublesome. It cannot adjust itself according to changes in the weather.
Allan

[Tony Hague]

http://www.itsnoteasybeinggreen.org

How does the greenhouse heat sink work?
Some details are in the book, but half the adventure is working out for yourself and thereby customising you solution.

[snip]

Interestingly, this revolutionary new idea was described almost identically in kitchen garden magazine a few years earlier - it was an insulated box of large pebbles, a small fan and a vertical tube to the apex of the greenhouse.

I tried it, but using a bottles of water as a thermal store.
(glass has a specific heat capacity of about 670 J/kg/K, whereas water is about 6 times better: 4200 J/kg/K). Even still, by my calculations I expected it to be pretty ineffective. I was correct. Presumably a pretty large mass of glass is needed ?

[Allan]

If you are into garden and greenhouse heating you may find the products of this company very reasonably priced. They will sell to private individuals.Even therir 'gifts' range is useful.

http://www.etiltd.co.uk/index1.htm
Allan

[Geoff]

I'd suggest insulation - big bubbles - and electricity. If you don't mind the extra capital to save running costs control the heater with a rodstat which is more accurate than built-in stats. This means you can set it lower to guarantee frost free as the on and off temperatures are closer together.
I've permanently bubble wrapped the North side and made Correx panels for the South side that are easy to remove and improve the light as the weather gets better. Can also pop them back in if Spring goes into reverse.