Coldframe heaters

[peterb]

Hi- Water reradiates heat fairly slowly and is a good way to keep temps just above freezing. Many passive solar designs incorporate large black tanks of water under benches that don't even have to get very warm during the day to keep air temps at or slightly above freezing overnight. (depending, of course, on how cold it gets and for how long).

peterb

[cactusplantqueen]

i've put some camping lamps with telight candles in, one in my cold frame and 1 in my greenhouse, and all load of plastic bottles with hot water in, i put them all slightely closer to my cacti than my other garden half hardy plants, when i was in there i could take my jacket off and feel slightely cool. So it should keep the frost at bay hope so

[cactusplantqueen]

ok, going to change hot water bottles, so theyre hot when it gets really cold, will probably go out there again 11pm and then at 1am and then at 4am and then at 7 am and then i can sleep on till 10am at which point i will got out there and remove all the bubble wrap etc, i have a sleeping dissorder so i sleep then wake up a lot throughout the night, and i dont go to school so it works out! the effort, these plants better grow

[CoronaCactus]

Thats quite the schedule to keep

[peter]

i have a sleeping dissorder

If so I wouldn't do it! Try out grave candles!

[kaktus]

How about a heating pad which are used for terrariums?
You can hook it up to a thermostate or a timer
Or a heating cable which produce less heat

You will find them in petshops

[cactusplantqueen]

dont have electric to it, just changed the bottles, its quite exciting actually, next scheduled bottle change: 11pm, see u then

[plantlover]

you said -3oc, is that -3 celsius?

Seeing your pictures, it looks like your cold frame & plants were on a patio. If they were, it probably would be a good idea to place a sheet of insulation board into the base to put the plants on so they are not touching the cold patio.

[cactusplantqueen]

yeah, 3 degrees c, cant do the symbol, will have to buy a couple more packs as well then oh well, when my perfect garden is finished next year it will have been worth it.

[plantlover]

So I am a little more confused. Are you at 3 degrees above freezing water or 3 degrees below freezing water?

I would go for large diameter candles that are in glass jars. But I do not know if those are available over there, as they are over here. They would burn longer and they would keep the wax in the jars instead of running down the side of the candle.

Here is a link to a temperature conversion chart that shows celsius temp and fahrenheit temp. We here in the USA use the fahrenheit temp.


http://www.texloc.com/closet/cl_cel_fah_chart.html

Temps here in the St Louis, Missouri area can get as cold as 0 degrees F (-18 celsius) during the winter, and sometimes it even gets colder then that. I remeber a winter it got down to -18 F (-28 celius).

It looks like you got your answer you were looking for on your original question of how to heat a cold frame. What do you think?

[CoronaCactus]

Would the smoke from the candles have any ill effect on the cacti? Probably not in there long enough to do any harm anyway...

I agree, it's a very efficient and inexpensive way to heat it, especially having them in jars, but had to ask about the smoke...

BTW, heat and coldframe in the same sentence is such an oxymoron

[cactusplantqueen]

3 degrees below freezing point, freezing point is at 0 degrees celcius, so -3 degrees celsius is 3 degrees below freezing point, i found some bigger candles so will use then tonight, the tealights burned through by this morning and it was too dark to replace them so at 3am i changed the hot water bottles and when i got up at 7am the coldframe wasnt freezing, tonight i'll put the candles in at 9pm, check on them at 12am then sleep until 7 am then i will check them again then go back to sleep until 10am, last night was fun and i got enough sleep just too much hassle to put my wellies on in early hourse

[hob]

So I am a little more confused. Are you at 3 degrees above freezing water or 3 degrees below freezing water?

-3s or in your terms 26.6f is how i see it in my part of the uk

[plantlover]

Did the bigger candles keep it nice and warm in the cold frame?
Today our temps were 25°C to 13°C. In the next couple days they are telling us we will see lows in the -5ºC and highs of 3ºC.

[cactusplantqueen]

they burned through the night i didnt have any jars to put them in so i put them in some used and clean tin cans, so the ceiling tiles (polystyrene tiles) wouldnt catch alight! They dont make it warm but a few degrees warmer than frost