Topic: Soil Warming Cables

[Susiebelle]

Has anyone recently constructed a bed using these cables? I am try to source a really. really good price but all the website seem to be selling at much the same price. I was looking for a Parasene 12 mtre + thermostat.  THere was one site but no stock, not sure whether they ever had any or not.
Would be grateful if anyone knows of a keenly priced source.
Many thanks

[Susiebelle]

Can nobody help me?

[daveyboi]

I bought mine from
 http://www.thegardensuperstore.co.uk/acatalog/Soil_Warming_Cables.html

earlier this year.

Or you could try looking at
http://www.thermoforce.co.uk/soil_warming_thermostats.htm

Then try a search on the chosen product code

[Susiebelle]

Thanks Daveyboi, will report back.

[daveyboi]

Did you mange to get your soil warming cable?

[Susiebelle]

Wanted to report back -
I have my lovely warming cable and thermostat I ended up buying from the  Allotment shop in neighbouring town, similar price and I like to support them when I can. I have the bed all made up - a bit of a 'faff' really as I had electricity installed in g.house but true to form when I tried to use it - it failed and the electrician was in Tenerife (lucky so & so) anyway now sorted.

The instructions for the warming cable state 'keep sand moist' but also states 'sand must not be wet how do you keep sand moist without wetting it?
Would appreciate any  advice from others using this sort of warming bench idea.
Many thanks.

[daveyboi]

I found that the water from watering the trays and pots on the sand bed kept it nicely moist as the sand was damp when I made mine.

Basically they are saying do not drown or let dry out completely as the moisture helps even out the heat through the bed.

Glad you got it sorted and now you can enjoy.
Also you have reminded me I need to do some painting over the holidays lols

[Tee Gee]

The instructions for the warming cable state 'keep sand moist' but also states 'sand must not be wet how do you keep sand moist without wetting it?

To answer your question!

Typical sales gobble de gook written by a techie salesman not a regular user.

Back to the point!

Because you are wetting sand you will find that any surplus water will run off providing you have made provision for this to happen.

The base of my bed is a slab of polystyrene anout an inch thick so the surplus water escapes from around the sides of this.

Then I have spread about two inch of sand on this, next, I laid out my cable and topped that with another layer of sand.

Next; Fitted the 'stat into the top layer of sand.

Gave the bed a good soaking, the surplus water  drains off and now;

it is not wet but  it is  moist to comply with the jargon.

Then my secret ingredient that sales jargon does not give you;

What you will normally find, depending on what temperatures you are working with is.............the sand dries out!

OK one can wet it again which is not as easy as it sounds particularly when the bed is covered with trays of propagating equipment so to overcome this I place a sheet of pvc/polythene over the wetted sand and this does two things namely;

The sand does not dry out because the condensation formed under the pvc keeps the sand moist, and it spreads the heat better.

So one soaking lasts a season.

The other thing is; the pvc saves the sand being contaminated/mixed with compost that drains out of the propagating trays meaning the sand lasts for years.

and there you have it!...............my way!

[Susiebelle]

Thanks to both of you :-* :-*

Wish I had asked for advice before construction would have made decipghering 'gobbly gook' at lot easier.  The pvc on top of sand has to be a winner - so simple when some one points it out - many thanks

[davejg]

Thanks for that Tee Gee I want to build on for my new greenhouse fter christmas, I am now in full scrounger mode for all the bits you mentioned  ::)

[pumkinlover]

Eek! my soil warming cable was bought over 35 years ago, still works and I never knew you should keep it damp!! :-[ :-[
Thanks again A4A  :D

[sunloving]

I think its just that wet sand transmits heat more efficently than the cable in dry sand. 
ever taken anything out of the oven with a damp tea towel?
x sunloving

[pumkinlover]

Err... no .. but I won't now Thanks!!
Anne x

[plotstoeat]

I am new to this site and found this thread really useful. I bought a soil warming cable with my greenhouse two years ago but haven't got around to using it yet. Plan to do it in the next couple of weeks. Is there an ideal depth for the box? Is it practical to put compost directly on the top PVC layer rather than using trays?

[hippydave]

I am new to this site and found this thread really useful. I bought a soil warming cable with my greenhouse two years ago but haven't got around to using it yet. Plan to do it in the next couple of weeks. Is there an ideal depth for the box? Is it practical to put compost directly on the top PVC layer rather than using trays?

You dont want compost on the top layer you want sand, grow things in pots and trays not into the sand the warmth encourages the roots aswell as top growth. I just use 3" of sand in mine but Tee Gee's method sound very good.

[goodlife]

The idea of putting some sand down over the pvc layer is that the damp sand will ensure even temperature distribution under the trays and pots..if you were to put compost directly on it will dry out really quicly,,it may come too hot around cuttings and seeds...if you would get desease in you compost, it would infect the whole lot...in trays you can remove the trouble and rest would still be fine ;)
So..yes..you could put compost straight on..but it may create more problems than it is worth it.
Capillary matting can be used too instead of sand..and it is easier to change as and when things go bit grubby but sand is cheaper.
I've used both but personally I prefer sand

[plotstoeat]

Useful advice. Thanks. Found this link which confirms much of what has been said.

http://www.backwoodshome.com/articles2/sanders92.html

Ken

[Two Choices]

Excellent thread and my set up is very similar to TG's. After the initial watering I use a new dustbin liner over the wet sand, it keeps the moisture in and stops any 'nasties' growing in the sand. I also give the sand a soaking every couple of years with diluted Jeyes fluid, just in case.

One point for anyone building their first heated bed is to remember the weight of all that sand (my bed is 4ft X 2.5 ft) and to either 'beef up' their shelving or be ready to if building it in situ.  Hope this helps TC.