I have a number of young shrubs, eg daphnes and hebes, that I am raising. They are also in 1l pots and they just sit outside with no protection except for the wall that they sit behind. I have done this for years without any harm. If I had more in the way of frame lights I might rig one of these over them to protect from deep snow. However, the lights that I have are used to cover plants that I consider to be more important.

Hi Bulbaholic. I am trying to picture what frame lights are. I read somewhere that when young plants are in small pots in winter, a certain part of the compost in the pot can freeze, and then comes along some rain, and drainage is thus impaired in part of it due to the frozen bit, and then some rotting can happen. This is what I had been concerned about. Sorry description of process is a bit vague. Such is my memory. Am I making sense to you at all? Either way, you seem to be saying there is nothing to worry about. Wishing you a happy Christmas.

PS: Now you can see my lovely mush, just as i can see your lovely mush.

You are quite correct in what you say, Jonah. The compost will freeze and water will collect on top of the pot. If the compost has not thawed within a few days allowing normal drainage I then tip the water off. This would be a very rare occurence.
'Frame lights' are a term for the glass lids that go over a cold frame. I have cold frames but also use loose lights (actually old windows) supported on blocks over other pots. If you use loose lights then make sure that they are weighted down. They don't take kindly to being lifted and then dropped by the wind!

Personally I'd get young pots out of pots and into the ground.

Small tubs can freeze solid in winter and although many shrubs and plants can cope with this many can't.

I think I will try to get my young hebes, euonymus and jasmine out of my 1 litre pots and into the ground then. Sooner the better. Mind you, the weather seems set to stay mild for a while yet. ... Just one further question though: I have a lot of winter heathers in approx 2 litre size pots, darlyensis mostly. Are these tough enough to take absolutely anything in terms of weather phenomenon?

The 2 l pots will be fine. I overwinter lots of plants in 1lt pots and the fact that they are all grouped together minimises the problems. Like Bulbaholic they also get some protection from the wall.

Re the heathers - yes they are.

re: the heathers

I used to grow and over winter 5000+ darleyensis heathers in pots on my plant nursery from half a litre up to 2 litres.

They are one of the toughest plants I know and I never lost even one over winter.

Wow! Heathers are cool customers.

If you don't really want to plant out just yet, and the weather is set to get really, really cold, if you have bare soil in your raised beds, you can always just bury the pots in there till spring. That'll protect the roots from cold.
Mind you, at the moment, they're at more risk of flooding than they are of freezing...

Must invent a mini umbrella for each. Something Bahaman.