[jaycee]

What is the best way to lay the cables?
Wondering at what depth the sand(?) should be under and over them.
Should you them cover the whole when the cables are in with polythene then a capillary matting......
Need ABC please.
Not found a WEB site that seems to explain to a complete novice.

[Gwiz]

I've only ever used them on a bench. we made a box on the top of a bench, filled it to a third depth with sharp sand, then ran the cables. we then drilled a hole through the side of the box to fit a thermostat, and then filled to two thirds depth with more sharp sand. as far as I know it's still working after 10 or more years.
It can be expensive to run them them. do you need a whole area of soil warming cables, or could you make do with a propagator?

have you had a look here?
http://www.twowests.co.uk/TwoWestsSite/pages/cm/cm.asp?sCCPage=SWC

[jaycee]

I laid the soil cables a couple of years ago but don`t seem to get much warmth at all from them. The sand is very damp and I wondered if I had put polystyrene underneath the sand whether this would have been better.
There is power going to the cables.
I want to progagate quite a lot of seeds I don`t think it would ever get warm enough on the cables for tomato , celery seedlings etc to germinate.
I have a small propagator which I use for this purpose but need more space for other seedlings.

[Gwiz]

yep, i reckon that the 'styrene would be a good idear, at least that would cut down on the amount of heat lost through the bottom. Do you cover your seeds with a plate of glass and some newspaper? that would conserve a bit of heat as well. The only draw back being you must check it every day, and take the paper off when they start to come through.( but you proberly know that allready :oops: )

[PAH48]

Hi..Noted on the Two Wests link Gwiz kindly passed on, quote;- never lay cables in " peat, vermiculite or perlite".
I presume for the same reasons as in the building trade with polystrene balls, used to buy great big bag fulls, tip between joists in loft, for insulation.
Its now a No-No, the stuff was found to dry out and perish the outer cable
covering. ( fire prob's regs ect)
Vermiculite again used to be used for loft insulation and between floors as a sound barrier, I believe thats also a No No now for the same reasons.

Hope that helps, don't wish to be the bearer of bad news, but I'd certainly check out the current regs...Bye PAH

[jaycee]

Just been in the greenhouse and I think I have just too much sand on top of the cables. Additional staging coming soon so I am going to re lay the cables with less sand and hope the heat will get through to the seeds.
I notice that T W Elliot are selling an electric blanket that stands on polystyrene pads but I presume that these will be not be in contact and well away from the heating elements
Thanks for the input

[PAH48]

Hi ...Jaycee...wasn't tring to lay damp squids or out, over the past few years a lot of the lads I know in the trade are picking up a loada house rewires, just thought I'd mention it, could always try the old rockwool  :?:

Thats what we've all gone back to, even being used in caverty walls now.

Best of luck with your project..PAH

[shaun]

hi jay,you might be better making a box with a glass lid on it to keep the heat in,also aswel has the cables under the sand you might consider putting some around the sides to give a high air temperature like this one i made earlier  

[jaycee]

Posted a reply yesterday but looks like it got lost in the system!
Are those lovely perky little seedling tomatoes? Looks really warm and cozy in there....in fact with this horrible heavy cold I have recently developed I wouldn`t mind curling up in there myself. J.
P.S. are the soil cables expensive to run?