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Greenhouse - am baffled, please help

corianderwhishcorianderwhish Posts: 22
in Problem solving
Hello, any advice on our ‘greenhouse’ would be hugely appreciated. 

We bought a ‘flyaway’ greenhouse (6’ long x 4’ wide x 6’ high) and assembled it about 6 weeks ago as an easy and economical introduction to all things greenhousery. The temperature climbs satisfactorily in the day, but at night it drops faster than the proverbial stone, often ending up 3-4° colder than the outside temperature.  On the first night it was -2° outside and -6° inside.  And things have not really improved, even with a paraffin heater running 24 hours a day for the past week it is still dropping to 0° in there at night. We knew this wouldn’t be as good as a ‘proper’ greenhouse, but we did think it would at least be better than nothing.  And until we can sort it out, my one and only window with an inside sill and my kitchen are full to bursting with veg that we have no space to put into bigger pots. 

Does anyone have an ideas, please, how we can keep the heat inside at night?  I am disproportionately upset as I had such plans for so much veg growing with the extra space and longer season we’d have. 

Posts

  • barry islandbarry island Posts: 1,847
    I can't think of why it would be colder in the flyaway than outside, I used to have a small flyaway not a walk in one and plants survived well in there even in very cold conditions I just swathed it in fleece and sometimes plastic tarpaulin, the more serious problem that I had with it was overheating during the day.
  • BobTheGardenerBobTheGardener Posts: 11,385
    Check your thermometers against each other - I've found the cheap electronic ones vary quite a bit.  One of mine consistently read 5C lower than the other so had to use a 3rd to check which one was faulty.
    A trowel in the hand is worth a thousand lost under a bush.
  • wild edgeswild edges Posts: 10,497
    Have you verified that the thermometer is correct? Unless it's sitting on a refrigerated surface it shouldn't be possible to drop in temperature beyond ambient.
    If you can keep your head, while those around you are losing theirs, you may not have grasped the seriousness of the situation.
  • JacquimcmahonJacquimcmahon Posts: 1,039
    Never had that problem either. I used the flimsy plastic greenhouses for a few years and only needed to insulate them in the hardest part of the winter. To be honest I’ve not found a totally reliable outside thermometer either so as everyone says things may not be as bad as they seem. If you are really worried one of the best insulators I found was those cheep things for windshields, silver side in it helps reflect the heat inwards .
    Marne la vallée, basically just outside Paris 🇫🇷, but definitely Scottish at heart.
  • KT53KT53 Posts: 9,016
    The only situation I can think of when that could happen is if the greenhouse is at the bottom of a dip.
  • NollieNollie Posts: 7,529
    I think that defies the laws of physics! Keeping a paraffin heater going 24hrs is also just chucking money and fossil fuel straight up into the atmosphere.

    First I would insulate the floor and tape up any flappy edges at the bottom. Then get a roll of bubblewrap and give it some insulation all around, overlapping the door zips and rig up a bubblewrap roller blind you can drop down at night over the doors. Alternatively bubblewrap or fleece seed trays and plants inside before the temperature begins to drop. Placing plants on sheets of polystyrene or similar also help retain heat at the bottom. I created 5-sided boxes (open topped) in my unheated poly from sheets of cork insulation and sat plants in them, then could throw a fleece over the top easily enough without squishing the plants.
    Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
  • Nanny BeachNanny Beach Posts: 8,719
    Yes Nollie has said it all.I actually used my cooking thermometer to check the electronic one because it's the most accurate
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