Advice sought on heated sand beds

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Hedge
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Advice sought on heated sand beds

Post by Hedge »

Can anyone give me general advice on sinking pots in sand, possibly with heating coils? I am thinking about setting up one with a large cold frame over it within a sheltered courtyard on either a south or west facing wall. The cold frame would be 120 cm by 60 cm and they also sell planking to make a raised bed underneath them

I really need to know what sort of sand is best, and what sort of heating cables. I have plants that are currently in plastic pots. The idea is to keep the roots above freezing, in the winter when temps here can go to -10.
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Terry S.

Re: Advice sought on heated sand beds

Post by Terry S. »

My hardy bulbs are plunged in childrens' play-pit sand. It is fine texture and clean.

The other tip is to put polystyrene foam sheet inside the base area before putting the sand in. This provides extra thermal insulation for the roots.
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Re: Advice sought on heated sand beds

Post by Eric Williams »

And of course please be careful with the electrical installation outdoors, we are talking about 240v here I presume ? Cheers
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Re: Advice sought on heated sand beds

Post by habanerocat »

Yea, the electrics are your biggest problem. If you can put the bed next to an external wall, then you can house the electrics indoors and just route the soil warming cable and thermostat cable through the wall. Otherwise you'll need to put them in a waterproof box.

As for the soil warming cables. I use these without any problems.

https://www.amazon.co.uk/Elixir-Gardens ... way&sr=8-1

Although I don't have one myself, people here rave about the Inkbird.

https://www.amazon.co.uk/Inkbird-Temper ... way&sr=8-2

Personally I wouldn't ever put soil next to timber again. Even if you line it with plastic it will rot sooner or later. At those temperatures you will need to insulate otherwise it'll ate electricity. Consider a cavity wall or at least a brick/stone/concrete wall with insulation underneath and inside.
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Hedge
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Re: Advice sought on heated sand beds

Post by Hedge »

Thank you alll for the information.

Long term, I shall not be here that long for things to rot, although I do intend to line with pond liner. It will be against a wall, so that should help.

Currently keeping house at 23degC all winter for nearly nonagenarian so used to huge electric bills!
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