Hi Davy
It is an 7½ft x 2½ft bench with a sand bed and a thermostatically controlled soil warming cable.
I think it is by far the cheapest way to propagate as I can get as much as 14 full sized 14"x 8 trays on the bed.
Then when you consider I can put four punnets in each tray that means I can have 56 trays of seedlings on the go at one time.
Add to that I sometimes even sub-divide my punnets if say I am growing two or three varieties of the same genus, meaning I have the potential to have up to a couple of hundred varieties on the go at any one time although I would have to say I have never gone this far.
The other thing is because I use 70c square pots for pricking out I can get around 200 pricked out plants on it.
Alternatively with bedding I usually use 24 cell tray inserts so this gives me the potential to grow on around 330 bedding plants at one time.
In practice I use a mixture of the above i.e. I can propagate seeds,root cuttings and /or grow pricked out plants at the same time.
The bed temperature is set to give me a soil temperature of around 60-70°F (15-21°C) which is plenty for sowing & cuttings.
The greenhouse never gets below 40°F (4°C) due to my thermostatically controlled fan heater, which up to press this year has rarely been needed.
Initially I use propagator lids on my trays to confine the highish heat generated around the tray until the seed have germinated then I remove the lids.
This procedure allows the seeds to have warm feet (roots) and cool heads (leaves) which I find usually makes for good growing conditions.
There was a time when I also used grow lights to assist with this process but I do not bother any more.
In terms of monitoring my heating, I have a wireless controlled monitor that relays the inside greenhouse temperature into the house so I do not have to leave the house to check if all is OK.
So all in all relative to the number of plants I grow each year, which is in excess of 1000 plants and in my hay day this might have been nearer 2000, I think have my heating costs at an acceptable level.
Finally the bench becomes just another bench in the summer when I switch off the power.
I think I could say that I have most of the boxes ticked in terms of heating my greenhouse.
If you have any other queries about my set up give me a shout and I will help out if I can...Tg