What is a frost free shed?

matn3nrOmKD

Hello

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!

Matthew

Obelixx

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.

Nanny Beach

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

matn3nrOmKD

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'!

Dovefromabove

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.  

Ferdinand2000

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.

Fairygirl

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.   

Loxley

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.

Obelixx

Get a thermometer!  One with a max and min feature will tell you if it's frost free.

monsejour15_lcRGdg8

@Obelixx - You obviously failed to understand the original question.

It's one that puzzled me and I'm glad to have seen some explanation.
For my purposes, I shall consider it to be a dry shed (or garage, etc) that stays above freezing.

Obelixx

Not good enough @monsejour15_lcRGdg8.   Staying above 0C is no guarantee that plants will be safe from frost if they are tender evergreens with moisture in their leaves or - as mentioned above - dahlia or other tuber containing moisture.  As @Lyn says, a minimum of 3C and more is a safer bet.