I think I see what you're saying, Bob - do you mean that the soil heats up during the day and then stays warm, like a storage radiator? In which case yes, I suppose there may be some benefit from clustering pots when there are significant fluctuations in temperature between day and night.The soil can radiate heat if the sun has provided it during the day (although not if it's constantly cold).
But I'd imagine that to make the most of this effect, you'd need to un-cluster the pots when the sun is shining, to allow the pots' surfaces to absorb the sun's warmth and heat up the soil. If they do get really cold, they'll take longer to thaw out if they're clustered together, won't they?
I'm very pleased that the RHS have introduced a new hardiness guide - will the plant labelling companies use it?? 3 guesses - 1 will do!
I have certainly seen online plants being described as hardy in mild parts of the UK...when you look into it (not on the site selling them) then sheltered, frost free and winter dry is the only way to keep them alive. That rules out everywhere (and yes I know parts of Ireland and the Scillies are very mild but they are also very wet and windy).
Another common thing I see are online suppliers not giving the plant/pot size supplied. They have pictures of a flowering mature plant in the height of summer. So when people get bare roots or a 9cm pot with a twig in it they feel robbed.
I ordered some wallflowers online, said they came in a 2litre pot. Which indeed they did, plugs pushed into a pot of compost! From a very well known female TV gardener! Another con.
I ordered some wallflowers online, said they came in a 2litre pot. Which indeed they did, plugs pushed into a pot of compost! From a very well known female TV gardener! Another con.
I had something similar. The plant was in a 1 litre pot and the roots where 9cm pot. It had fallen out and broke in transit because of it...
I ordered some wallflowers online, said they came in a 2litre pot. Which indeed they did, plugs pushed into a pot of compost! From a very well known female TV gardener! Another con.
I ordered some wallflowers online, said they came in a 2litre pot. Which indeed they did, plugs pushed into a pot of compost! From a very well known female TV gardener! Another con.
I had something similar. The plant was in a 1 litre pot and the roots where 9cm pot. It had fallen out and broke in transit because of it...
Most annoying! Hope you've both added these suppliers to this thread!:
In technical terms, the soil in the pots will radiate heat as infra-red radiation (heat) in all directions. If a pot is surrounded by other pots, some of this heat will be absorbed by the other pots instead of being lost to the environment. The effect of this is that (say) 10 pots clustered together will cool down more slowly than 10 pots spaced widely apart, so it is worth doing.
Heat has to come from somewhere though and the soil is not producing heat by itself. If the pots are in shade then there is no heat to radiate.
Posts
I think I see what you're saying, Bob - do you mean that the soil heats up during the day and then stays warm, like a storage radiator? In which case yes, I suppose there may be some benefit from clustering pots when there are significant fluctuations in temperature between day and night.The soil can radiate heat if the sun has provided it during the day (although not if it's constantly cold).
But I'd imagine that to make the most of this effect, you'd need to un-cluster the pots when the sun is shining, to allow the pots' surfaces to absorb the sun's warmth and heat up the soil. If they do get really cold, they'll take longer to thaw out if they're clustered together, won't they?
Highland Jeannie wrote (see)
I have certainly seen online plants being described as hardy in mild parts of the UK...when you look into it (not on the site selling them) then sheltered, frost free and winter dry is the only way to keep them alive. That rules out everywhere (and yes I know parts of Ireland and the Scillies are very mild but they are also very wet and windy).
Another common thing I see are online suppliers not giving the plant/pot size supplied. They have pictures of a flowering mature plant in the height of summer. So when people get bare roots or a 9cm pot with a twig in it they feel robbed.
I ordered some wallflowers online, said they came in a 2litre pot. Which indeed they did, plugs pushed into a pot of compost! From a very well known female TV gardener! Another con.
I had something similar. The plant was in a 1 litre pot and the roots where 9cm pot. It had fallen out and broke in transit because of it...
Most annoying! Hope you've both added these suppliers to this thread!:
http://www.gardenersworld.com/forum/talkback/name-n-shame/165744.html
I like to see what i am buying, go to the garden centre shop local.
i don't own a GH to raise plug plants in.
some plants are started in tiny plastic cages, or net, which can restrict the plants growth. especialy if let dryout.
Heat has to come from somewhere though and the soil is not producing heat by itself. If the pots are in shade then there is no heat to radiate.