Heating my new greenhouse

[Diane]

Herts Mike - you could use heat mats for the Stapeliads, as bottom heat is probably more important, therefore not needing to keep the whole greenhouse at a higher temp. Of course, you may have too many for this to be an option!

[Martin]

The biogreens are good but expensive I have 2 of them but alsonow use 2 of these

http://www.machinemart.co.uk/p/clarke-d ... tric-fan-2

Just as good on an external thermostat

[agavemad]

I also have two bio green heaters, they are good but I do use an independent thermostat.
Last year I also bought a machine mart heater and use an independent thermostat and they are very good and much cheaper.
The only real difference is the bio green is IP rated for outdoor use and the machine mart one is not. However I reckon if I don't water it, it will be ok The greenhouse is watertight and its not a damp/humid atmosphere as the plants don't get watered over winter.

[habanerocat]

There is a thread here worth reading in relation to my question below. I don't like digging up old threads so I decided to post here.

viewtopic.php?f=1&t=157342&hilit=frost+protection

Has anybody tried covering their plants with cardboard or bubble-wrap over the winter to save on electricity bills?
Does it cause a very hot micro-climate around the plants, causing scorching? Any other problems?

I'd be interested in hearing from anybody who has tried this. There was an interesting article in the journal a couple of years ago in relation to greenhouse heat retention. I must try dig it out and read it again.

[Chris43]

I use 2 x 3kw Biogreen Arizona fan heaters. I've found this adequate, though the original external thermostats failed after about 5 years, and I have used the Biogreen Therm 2 on each of them since. The actual heaters are very solid, and reliable.

There's a Biogreen Phoenix available on the For Sale forum!

[Cactusgirl]

Thanks to everyone for all the great advice and information! I think for this year only because I have only 100 plants I shall partition off the greenhouse and try to only heat the bit occupied. Started to look at heaters but will get one powerful enough for the whole greenhouse when it's eventually full. Have also looked at heat mats and tubular heaters and wondered if these could supplement the main fan heater? Also I'm now thinking that if I heat it to say 5 degrees minimum this will be adequate for most cacti? However what temperature do Lithops, aloes & haworthias etc need to survive winter in the greenhouse? I've got some nice examples of these from the Cactus marts and would hate to lose them! Thanks

[D^L]

5 degrees C is a good starting place, in fact many things will survive frost free provided they are dry. Lithops, the vast majority of cacti, haworthias, etc will be fine at this. The devil is slightly in the detail since there are things that will not do well at 5C, e.g. Melocacti, stuff from Brazil, and I expect some tropical Aloes though I have no experience of this. I thought Haworthia koehlmaniorum and mcmurtryi were also a bit sensitive but I think I killed mine by other means so have never tested temperature. Anything East African ought to be considered sensitive as well.
Cheers
David Lambie
Bristol

[D^L]

I'd just remind everyone that electricity and water do not mix well, especially if you are in a metal cage, like the one that often supports glass. Just take care when planning electricity in the greenhouse, ideally get professional advice.
Cheers
David Lambie
Bristol

[Cactusgirl]

Hi David thank you for the advice and I feel reassured my Lithops will be fine now outdoors. My electrician is dealing with all my electrics which means I have no worries - except what heater to buy of course! I will maybe look to get a tubular heater too and construct some kind of perspex mini greenhouse within for my blue cacti and see if I can keep them in their own 'micro climate'. Will be an interesting experiment in cacti temperature control I'm sure!

[Philip Greswell]

I spent money on the Dyson Hot and Cold fan which is thermostatically controlled with a hand held control to set it to the required temperature.It rotates from side to side.

See https://www.dyson.co.uk/fans-and-heater ... rview.html for a picture of it.

As I found out later, if there is a power cut, the heater goes off and does not come on again when the power is restored.So you have to re set it with the control.

So if you happened to be away for a few days in a very cold period, plants may be damaged because the heater does not automatically come on again.