Condensation.

Discussion in 'General Gardening Discussion' started by MattM, Feb 4, 2012.

  1. MattM

    MattM Apprentice Gardener

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    I wonder if anyone can tell if the levels of condensation I have are normal or ok. I have an 8x10 half shed half greenhouse type affair. The greenhouse is really just a 4x10 lean to onto a 4x10 pent shed. It's made of pine with plexiglass windows. It all sits on a slab base and is silicon sealed where needed.

    So....at the moment I have a large Vitopod propagator with an adjustable full length grow lamp that comes on automatically to give six extra hours of light at the end of the day and then switches off. Using these two together I can start practically any seeds or cuttings and they generally go.

    So....to keep all these little seedlings and cuttings going after they come out of the propagator and are potted on, Iv'e got an electric heater in the greenhouse to provide the heat they need. I thought that rather than just keep things alive and safe from frost, I'd keep the temperature at 7.5 C so that they would actually grow and so be ready to plant out when I needed them. The heater is on a BioGreen Thermo 2 thermostat and the temperature regulation is spot on.

    So....and I know this is a bit long winded, everything is working as planned, everything is growing well, the shelves are full of plants that I'm happy to say have been grown from seed and because of the size of the greenhouse, it's not costing a fortune to heat.

    But....the condensation inside is simply immense! It isn't running anywhere and the side glass isn't too bad but the roof panels have so much water in very large droplets that even just opening and shutting the door literally causes a down pour. I've tried taking it away but it's a losing battle as it just forms again over night. The plants are healthy and the air doesn't feel damp or stale but I am getting fed up of having to put on wet weather gear just to look in on things.

    I'm sorry for the extremely long build up to a seemingly small problem but I thought it would be best to say what I've got going on in there in case part of what I'm doing is the cause. I think I basically need to know if that level of condensation is normal, are my plants safe and should I be trying to stop it.


    Thanks all

    Matt.
     
  2. Phil A

    Phil A Guest

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    Its that time of year Matt. Sounds like you are doing the right thing & your plants are alive. Increasing ventilation will help, but then you will need to up the heating.
     
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    • ARMANDII

      ARMANDII Low Flying Administrator Staff Member

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      That's one of the problems with a long, narrow heated plastic windowed building I'm afraid:what: The heat is turning the cold damp air into warm moisture clinging to the windows and roof. Ziggy's right about ventilation but, as he says, that would drop your inside temperature defeating the object of the heating. One trick is to put a fan just below the height of the roof to move the warm damp air around the building, I think you'll find that should improve the situation:D
       
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      • lazydog

        lazydog Know nothing but willing to learn

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        Just a thought (a drunken one)would a de-humidifier help?
         
      • Kristen

        Kristen Under gardener

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        You need some ventilation I'm afraid. Silicon'ing the panels in has probably reduce the trickle ventilation. But ventilation will mean that air has to be heated (unless you can find, cheaply, and install a Mechanical Heat Recovery Ventilation system?)

        Get a bigger greenhouse and install it over the top :)
         
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        • MattM

          MattM Apprentice Gardener

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          Managed to give it a good airing today. No snow or frost around us and it was mild enough to open everything up. I took the chance to pot on a few dozen plants, sowed a few more into the propagator and moved some into the cold frame. All in all a nice few hours spent. Still had to wear at hat in the self watering greenhouse though :)
           
        • JWK

          JWK Gardener Staff Member

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          It's very difficult to avoid. You might run into problems with damping off eventually unless you can ventilate more (but then you lose heat!). So add a little Cheshunt compound when watering to keep it at bay.
           
        • pete

          pete Growing a bit of this and a bit of that....

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          Condensation is a real problem in a heated greenhouse in winter.

          The more you heat it the more condensation you get.

          Also the more watering you do the more condensation, so anything that's not actively growing should be kept slightly on the dry side.

          Is the propagator enclosed?

          If not your wasting heat and causing condensation.

          7.5C does not sound high enough to keep things growing once they come out of the propagator.

          To me it sounds like the old story of being able to germinate/ propagate,.... the easy bit.:)
          But growing on at this time of the year is not easy.

          The other point may be that if its a standard greenhouse the glazing is designed to shed condensation to the outside, if you silicone it tight, that cant happen.
           
        • Kristen

          Kristen Under gardener

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          Perfect that for the Summer months, Patent it and retire rich !!
           
        • Kristen

          Kristen Under gardener

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          Fling everything open on mild days. Whatever damp is getting under way will be given a bit of a run for its money then. Run an electric fan in there if you can (forgotten whether you have electricity in the greenhouse or not0. Be careful mixing water with electricity though ... an electric greenhouse heater with a "fan only" mode would be best, and shouldn't use a lot of electricity when its not "heating"

          "So add a little Cheshunt compound when watering to keep it at bay"

          Or the modern, non-banned, not-illegal, equivalent !!!
           
        • PeterS

          PeterS Total Gardener

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          Matt - I would agree with the others, its an occupational hazard. Ventilation would help - but it works against your heating.

          I get very heavy condensation in a summerhouse that I use to store plants over winter. In my case most of the water is bought into the summerhouse in the pots that the plants are in - its usually been raining in late autumn before the pots are moved inside. As the pots dry out the condensation gets less and finally stops, even though it may still be freezing outside. I wipe the inside surfaces down with a sponge to remove the water, as when the condensation is heavy enough it would take a very long time for the water to evaporate just with ventilation.
           
        • JWK

          JWK Gardener Staff Member

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          Oh yes, I'd forgotten is was no longer available :o

          Here's the alternative (but I've never tried it yet):
          Other Gardening Equipment

          "Unfortunately Cheshunt Compound has now been withdrawn from sale because of EEC regulations. However this new Dithane alternative should do the trick for those difficult seedlings ...."
           
        • pete

          pete Growing a bit of this and a bit of that....

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          Dithane has been around for yonks John.

          Its just that we now have to resort to using it for damping off problems.:)

          I still cant help thinking if seedlings are damping off its a problem with growing conditions, mainly

          growing seeds far too early.

          Can you still get Bordeaux mixture??
           
        • JWK

          JWK Gardener Staff Member

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          Dithane has been 'withdrawn' too pete :rolleyespink:

          The link I gave above is to something called "Bayer Fruit & Veg Disease Control" (a Dithane alternative)
           
        • pete

          pete Growing a bit of this and a bit of that....

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          Sorry John I miss read it:scratch:, it says this new Dithane alternative now that Cheshunt compound is not available.:rolleyespink:

          Anyway, what is it, it doesn't appear to say?
           
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