Soil warming cable - Propogator

I've ordered a soil warming cable today, so should just get it before Xmas.

Does anyone know if I should use builders or sharp sand in the propogator bed, I'm guessing builders as it will hold the moisture for longer, any thoughts?

Steve...

 

I have always (30yrs) use sharp sand under and over the cables with no trouble ...And I only stand my plants on the surface ,In the winter I only water the plants but in the late spring I water the sand as well. The last couple of years I have put a capillary matting over the sand which I keep wet in spring and for autumn when I root my geraniums and fuchsias .
I'm sure there are many variations on this ..

Dave

 

I've no idea why the cable should be kept damp either ??

Dave

 

I'be had this posted for me on another forum, which should be of some interest here.

Greenhouse Heating

Thanks go to Tee Gee for providing the link.

Shiney and Davy, have a look just after the photo's, it says "keeps the sand moist at all times, thus giving me good heat distribution."

Steve...

 

Well we learn something every day.....

Dave

 

Hi all,

Re-why I wet my sand!

A lot depends upon how your cable is laid out in the sand and how far apart the lines of cable are.

In my early days I found that I was getting 'hot spots' and needless to say (sods law) these seemed to occur under trays where I least wanted them.

So I tried wetting the sand and I found that the heat was distributed more evenly!

Then I found that the water was evapourating rather quickly so I covered the bed with a sheet of plastic and this did a couple of things;

1) The evapourating moisture condensed on the underside of the plastic and I found that I only needed to wet my sand once per season as opposed to weekly!

This is very handy when your bed is covered in seed trays, it means you don't have to remove and replace them every time you need to wet the sand!

2) The plastic keeps the sand free of compost that tends to seep out of trays and containers, so there was no need to change the sand every year, in fact the sand I am using is the original sand I put in and that was teens of years ago!

3) These are pictures of my bed in use as of a few days ago and how it is today;

So basically all it amounts to is;

Do what you think is best for you, I do ...Tg