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What is a frost free shed?


This is probably a stupid question but I'd really like a definitive answer as I need to know what I am supposed to be doing!

What is a 'frost free shed'? 

The term is used a great deal but I can't find out if it means "a shed where the temperature does not go below zero degrees" or "a shed that is dry that does go below zero degrees".

Thanks if advance to what I expect should be obvious but isn't to me!



  • ObelixxObelixx Vendée, Western FrancePosts: 22,691
    Frost can happen above 0C!   .8C at 8am here and a heavy frost and the metre down the garden registered 0.2C as the coldest at dawn.   I wouldn't want a wet shed.  It would rot and stuff in it wouldn't keep well.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • Nanny BeachNanny Beach Posts: 3,874
    Yes, you can get frost at 3c, I always assume that a shed,garage,which is closed (ie doors,windows is frost free, you wont ee any frost on your tools etc stored in there
  • Presumably you are thinking about overwintering plants in your shed ?  Depends what plants you are thinking of but basically a closed wooden structure which is dry would not produce "visible" frost - it may get pretty cold ( below 0 c ) but if there is no moisture, you should not see frost.
    Most plants, within reason, can put up with varying degrees of cold if the atmosphere is dry - the trouble usually occurs when damp and low temps are combined.
  • Thanks for your answers.  To summarise it is the dryness not the temperature that is the issue for a 'frost free shed'.  So if the shed is dry (which mine is) even if the temperature goes below zero in there it can be considered 'frost free'!

  • DovefromaboveDovefromabove Central Norfolk UKPosts: 65,303
    I wouldn't keep tender plants in a shed where the temperature went below 0C even if it's dry  ... after all, the air may be dry but the plants will contain moisture so would freeze which can cause structural damage to the plant cells.  Water will freeze without there being the white rime that we call frost or hoarfrost.  
    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh

  • Humidity is important too.

    Frost is water vapour condensing onto a freezing surface - literally frozen condensation.

    So there is a balance of 2 things that helps prevent it - dryness and a slightly warm surface.
    “Rivers know this ... we will get there in the end.”
  • As said previously, I think it would help if you specified what plants you are considering for the shed and what stage they are at - it will make a difference.
  • FairygirlFairygirl west central ScotlandPosts: 35,344
    I agree with @philippasmith2. It depends what you want to keep in there. Wet cold is a problem for lots of plants. 
    My shed is consistently damp from late summer/autumn onwards. I wouldn't entertain keeping anything in there over winter if it needed protection, as it would be damp, and certainly isn't frost free once winter arrives. 
    Something like dahlias, or bulbs, for example, would suffer badly. However,  another container in there to give further protection from cold/damp, could possibly work.  :)  
    It's a place where beautiful isn't enough of a word....

  • LoxleyLoxley Posts: 2,954
    edited November 2020
    I'd class a brick outhouse or lean-to shed up against the house as a 'frost free shed', as the house keeps the temperature up a bit compared to a shed down at the bottom of the garden with all four walls exposed to the weather. An isolated wooden shed wouldn't offer much thermal protection if temperatures dipped below freezing for several nights. When people talk about a frost free shed, I tend to think of things that can withstand a bit of cold while dormant and would actually be borderline hardy in much of England if given a mild winter e.g. dahlias. Rather than desperately tender things that instantly die if the temperature gets anywhere close to freezing.
  • ObelixxObelixx Vendée, Western FrancePosts: 22,691
    Get a thermometer!  One with a max and min feature will tell you if it's frost free.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
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