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Frost proofing a greenhouse

I have a small lean-to greenhouse against the south facing wall of the brick house; it's probably 6 foot high, 8 foot wide and 2 foot deep.

I have ordered a small paraffin 'Parsene' heater, and I plan to overwinter more tender succulents, some aeoniums, some jade plants (crassula?). I will light the heater when frost's forecast.

Assuming we don't get a week or more of constant below minus C temperatures like that winter - was it 5 years ago?- do you think that'll be enough? It'll be a real faff to put bubble wrap up as additional insulation due to the design!


  • BobTheGardenerBobTheGardener Leicestershire, UKPosts: 9,877

    One problem with paraffin heaters is that they generate a lot of moisture which produces condensation and that can cause things to rot, so make sure you ventilate it during the day.  A surprising amount of protection can be obtained by draping fleece over your plants, so perhaps also do that with any particularly tender ones during very cold spells.

    Last edited: 02 October 2016 17:42:59

    A trowel in the hand is worth a thousand lost under a bush.
  • miljeemiljee Posts: 3

    Thanks, didn't realise condensation might be a problem, and yes, I will get some fleece as well.

  • PalaisglidePalaisglide Posts: 3,414

    Miljee I did away with paraffin years ago for the reason Bob states condensation plus you need to keep the wick short and clean which means trimming it everyday or you go out one day to a sooted up GH.

    Screw some Bubble wrap to the wall above the GH roll it down at night with a couple of bricks on the bottom and roll it up each morning, a couple of heavy elastic bands or some string will keep it rolled. My GH is a large leanto so I have electrics and use a fan heater on frost guard, a small area gets bubble wrapped for tender plants and this has worked for many years now. Many plants are hardier than we think and can stand a bit of frost it is fast thawing that causes problems. 


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