greenhouse heating

[Snadger]

If you had an oil filled radiator in last year you must have electricity to greenhouse? If so, the cheapest way to give some bottom heat is with a bench filed with a couple of inches of sand and a soil warming cable embedded in it methinks.

[rary]

^^^^ As Snadger has said an electric cable in a bed of sand will work well and be a reasonable cost to run, but you miss the pleasure of trying something different, whither it works or not, as for the fan if the temperature is going to go below zero cover plants with fleece, I have had success down to -5 so

[Doncasterpaul]

a simple black water butt full of water does work quite well as a solar collector/heater and if possible cover or insulate the north side of your green house with something black. this will not really heat your green house, but it will raise it by a degree or two which will help prevent frost. with regards to your plans for a heater. i have actually tried the exact same thing. but my solar panel was not big enough to cope with the demand of the central heating pump. having said that it did work

[MarkPelican]

Following the above comment, I put a waterbutt of water in my polytunnel last year and used a garden solar pump to run water around a black painted radiator and into the waterbutt. I then measured the temperature of the outside, polytunnel and water in the butt every 10 minutes using a Raspberry Pi. The result, as expected, was that the water heated up during the day (more on sunny days) and cooled down over night so it was putting some heat into the polytunnel. The temperature in the tunnel overnight was usually one degree warmer than the outside but I don't think the waterbutt made enough difference to make anything grow that wouldn't have grown anyway.

[Billy's lad]

I have rescued my dads old eltex heater and plan on getting some parrafin later

[rary]

I have rescued my dads old eltex heater and plan on getting some parrafin later

Remember paraffin heaters help create condensation within greenhouses and poly tunnels

[SarrissUK]

Is that bad Rary? I know it increases moisture levels perhaps, but is it bad in any other way?

[rary]

when there is no air movement a damp atmosphere can create ideal conditions for mould (botrytis) and other fungal growths, it can lead to health problems not only to your plants but also yourself especially if you are asthmatic evidently that is in severe cases but the possibility is there

[SarrissUK]

Ahh.. that makes sense. And it sounds scary. Thank you Rary

[Derbydal]

I have rescued my dads old eltex heater and plan on getting some parrafin later

hi you may find parrafin expensive ,if you can get hold of household heating oil it is keroseene which is same as parrafin but half the price ! it as a 28 second burn rate same as parrafin and your Eltex will run ok with it, iv'e been trying mine with red diesel but it seems to coke up the wicks after two days .atb Dal.

[Billy's lad]

Ok good tip about the kerosene