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What are the figures related to the temperature gain using tealight candles in a greenhouse?

2

Posts

  • In theory a big container of water should keep the temperature of the greenhouse just above freezing until it is itself frozen solid.
  • Bee witchedBee witched Posts: 1,295
    Hi @Rubytoo,

    Thanks for sharing your experience with the nightlights .... 

    As a beekeeper we have a lot of beeswax which we make into candles.
    They are just pure beeswax with nothing added so there shouldn't be the problems that Pete has outlined.
    They usually last between 10 - 12 hours, so I might try using some in my greenhouse.

    Not sure how many would be needed as the greenhouse is 14' x 8'.

    Probably soya candles would be less of an issue than paraffin.

    Bee x


    Gardener and beekeeper in beautiful Scottish Borders  

    A single bee creates just one twelfth of a teaspoon of honey in her lifetime
  • RubytooRubytoo Posts: 1,630
    Hi @Bee witched
    I am sorry I didn't read everything earlier, bit grumpy today hurried and hassled :)

    How lovely you make candles. I have no idea if you could realistically heat your green house with them, perhaps a smaller section off bit to keep frost free. That is a big space.
    10 to 12 hour candles sound good too.
    You could light them before midnight, and not have to get up early either :D

    I did not mention the humidity it does get quite high but then it is a small temporary measure "emergency" situation for me. I wiped the roof off yesterday evening and this morning. Actually have the door open as it has "warmed up" ( I use the term loosely!).

    Proper greenhouses have roof vents to lose excess humidity?
    I just assumed small blow aways which do not usually have vents at the top would get wetter anyway.

    I leave it open unless it is going to or almost going to freeze.

  • Lizzie27Lizzie27 Posts: 12,494
    I tried the tea candle inside an upside down terracotta pot on the stone floor of my small glass leanto greenhouse last year. The theory was that the candle would warm the terracotta pot up which would help to keep the greenhouse frost free  It didn't work for me as it kept going out.
    North East Somerset - Clay soil over limestone
  • Lizzie27Lizzie27 Posts: 12,494
    P.S  I'd be very wary of leaving lit candles overnight in a plastic greenhouse.
    North East Somerset - Clay soil over limestone
  • nutcutletnutcutlet Posts: 27,445
    I look at the size of my GH and the size of those candles and wonder just how many it would take  :) 


    In the sticks near Peterborough
  • Papi JoPapi Jo Posts: 4,254
    Lizzie27 said:
    I tried the tea candle inside an upside down terracotta pot on the stone floor of my small glass leanto greenhouse last year. The theory was that the candle would warm the terracotta pot up which would help to keep the greenhouse frost free  It didn't work for me as it kept going out.
    You should have put it on a leash. ;)
  • AnniDAnniD Posts: 12,585
    Papi Jo said:
    Lizzie27 said:
    I tried the tea candle inside an upside down terracotta pot on the stone floor of my small glass leanto greenhouse last year. The theory was that the candle would warm the terracotta pot up which would help to keep the greenhouse frost free  It didn't work for me as it kept going out.
    You should have put it on a leash. ;)
    Very good Papi Jo, made me groan! I have read this thread with interest,  must admit l would only try it as a last resort and with only my most precious "babies" in a small section of a (metal) coldframe, with the tealights in jars. Hopefully it won't come to that though......
  • treehugger80treehugger80 Posts: 1,923
    i have a slimline water butt in my home greenhouse and a 1000 ltr bowser in my work polytunnel, (both full of water) i use them as space heaters,

    during the day they 'heat' up as the greenhouse warms, even in winter on the clear days (when you get a frost at night) my home greenhouse goes up to 6 or 7 degrees minimum (sometimes more), then they give that heat out at night, i have a shelf above them for really tender stuff. Even during the beast last year the lowest it got in there was -1 (outside hit -16)

    then during the summer they reduce the heat of the day by doing the same thing and give out a little heat at night.
  • The terra-cotta pots and candles work wonders for me last year. This year hubby gave me a small tube heater for my mini greenhouses. I have three in a line and the heater keeps the middle one well above zero and the one either side just above zero. So far everything inside is doing great (loads of cuttings taken in autumn). Really economical as we only turn on when necessary.
    Marne la vallée, basically just outside Paris 🇫🇷, but definitely Scottish at heart.
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