Heat Box

We often talk about Light-Boxes, but has anyone every tried to make a Heat-Box?

There seems to be a lot of tropical stuff like Cannas, Gingers and Gloriosa etc that need heat to get them out of bed in the spring. And with our climate they often don't start till quite late. So how about a box that bakes them. As long as its very well insulated, it probably wouldn't cost much to run it - and if its in the house any heat it uses will contribute to the house heating.

It probably wouldn't need any light, which would make it more complicated, as once a rhizome had started to sprout, it would be committed and would continue to grow outside of the box as long as its wasn't freezing.

Any thoughts? and any idea how hot you could go. Cannas, Gingers and Gloriosa probably all experience 90F in their natural environment?

 

In our house we don't have a tumble drier, but my dad does does, and when its on it blows a lot of hot air into the kitchen. So much that to make the temperature bearable, he has to leave the back door open. I've often thought about just how much of a waste this is. I wonder if it could be connected via a flexi-pipe into your heat box, before continuing on its way. Just a thought. Probably no good, but the idea's is out there now

 

Interesting idea Clueless. The problem is that it will be only intermittent. But it does seem such a shame to waste heat.

 

I put mine on top of the boiler, but like the Tumble its intermittent.

Would soil warming cables do? If so could perhaps toggle between propagating box and hot box. e.g. replace the transparent summer-cover, for propagating, with an insulated one of Kingspan / Polystyrene - assuming that the soil heating cables would do the trick.

otherwise just stand them on a reptile heating mat? (Cheap as chips off eBay; variety of sizes available)

 

I was looking at the same thing as well and as much as I wish that they would be some sort of solar system heating , there is nothing out here for greenhouse.
I`ve recently bought a 180w electric heating for heating for the greenhouse and I`ve used this webside to calculate the cost.
http://www.sust-it.net/energy_calculator.php?supplier=9

overall if i keep it on all 6 months 24/7 it would cost me around £120 in electricity consume.....
I`m thinking , if all my plants really worth so much or simple take them inside and hope for the best outside as a electricity price rise of 8% will be even more expencive.

 

Sal - I think the key for heating a greenhouse is that an electrical heater will be controlled by a thermostat. Therefore its the length of time that its on for that determines the cost.

The first winter I heated a 10' by 8' summerhouse, it was quite mild and it only cost £3 for the whole winter. The reason it was so low was that the thermostat was only set at 1C ( to keep it frost free) and the temperature very rarely tried to go below that. However if I had set the temperature at 5C, there would have been a much longer period when the temperature tried to go below that, and it would have cost a lot more - perhaps 10 or 20 times as much. Thats why I like to use a power consumption meter to tell me exactly how much electricity has been used.

I think a heat box may be quite cheap to run. If you put a 60 watt incandescent bulb (if you can find one) in a closed box that is extremely well insulated, you could quite possible get a temperature of 30C. It all depends on how much insulation there is.

 

They were outlawed for normal domestic lighting, but not for special purposes including novelty. Therefore, for example, you can still buy this:

http://www.maplin.co.uk/blacklight-...ch&utm_campaign=KJ65V&utm_content=UV+Lighting

I happen to have this exact kit, which I've had for years (bought it because I love the light of dawn, and was hoping to recreate it to some small extent at home). I'm thinking of incorporating it into my 'grow cabinet' project. Granted the light probably wont be much use to the plants (I don't know if ultraviolet plays a role in photosynthesis and even if it does, that bulb isn't going to generate much light), but it might help, and it will generate heat at least.

 

Sometime at work i use Celotex , for a joke my collegue made a box out of it just to keep is tea cup hot , it actually stay hot for around 3 hrs , plus Celotex have one side light reflex film on it .....a box made out of it with a ligh in ....job done.

Once i`ve seen an outdoor fishtank with tropical fish in , made out of an old fridge , the insulation of the fridge is one of the best you can get......basicly an old small fridge , without the gas , but just the light in it may do the job as well.
don`t have space otherwise i would have been on the project straight away .

I know that a termostat it would be much better , but at the moment i need to dry all the humidity out the greenhouse , it seams to work ...as fungus and mould kills more plants then the actual cold.

 

If you are putting a bulb in a hot box,as a source of heating, then Infra Red bulb probably best? We have one somewhere, left over from a deep tissue muscle injury where the heat was prescribed to help it heal.

But I think soil heating, to heat the soil in the pot, more important than the ambient temperature.

Re: Fungus & Mould. My strategy is to keep the air moving. Small fan moving the air, and open the doors / vents to allow fresh air in on days when the outside is warm enough [in the depths of Winter I mean]

 

I agree, you want the heat in the soil. Maybe a heating pad, covered with one of those transparent plastic storage boxes that I see in DIY stores. They are quite large and pretty cheap, and I keep looking at them and thinking of them in terms of a cloche.

Perhaps you could put a duvet over it at night and then put it in a sunny position during the day. That way you could get heat and light. It would really be just a big propagator.

 

Wow we have just invented the home made propagator .

 

I made a heated propagator a couple of years with one of those heat mats.
The highest temperature I managed to get was around 29'c.
Lined it with aluminium foil and placed a sheet of glass over the top
This was in a un heated greenhouse. The average temperature was around 23-24
Can't justify heating my greenhouse not enough tender plants yet

 

Nice job Mowgley. I think propagators generally raise the temperature by about 5C. Wilkipedia quotes average max temps in UK as :-
Min Max
Jan 1.1C 6.6C
Feb 1.0C 6.9C
Mar 2.4C 9.3C
Apr 3.6C 11.7C
May 6.3C 15.4C
Jun 9.1C 18.1C

An extra 5C doesn't sound like much, but its the difference between Jan and May as regards minimum temperature, and Jan and Apr as regards maximum temperature.