Topic: Busy Hotbed

[Tee Gee]

I think I mentioned the other day that I have made a start and this is how my hotbed looked this morning:

Left end of hotbed:



Right end of hotbed:



Closer look of hotbed with propagator covers taken off:



Like many things they age and my coldframe has well and truly aged, and was in need of some serious repair for this year. i.e. it needed two new lids.

I did think of partially removing it and putting the  8'x6' I have on the allotment in its place but came to the conclusion it would be a bit intrusive on the overall look of the garden so I pumped for these:



This was my original coldframe which I built around 1985.



I think you will agree that the new ones look much better but I don't think these will last thirty+ years.

[daveyboi]

Looking good Tee Gee !!

Just trying to work out your setup here and  was wondering whether this is a manure hotbed or a bench with a sand bed with soil warming cable.

[Tee Gee]

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

[daveyboi]

Thanks for the fully detailed explanation which is very useful and much along the lines I thought it would be.
Just a further question do you use horticultural sand or have you got away with using builders sharp sand? I have used horticultural in my small setup but it is so expensive I should imagine on a bench this size.

Thanks Davy

[Tee Gee]

It is builders sharp sand and has been in place for around twenty years.

To keep it clean I place a sheet of visqueen (Builders h/d polythene)I also think that this prevents the sand from drying out as much as it did in my learning years.

What I find is that the constant thermostatic switching on and off the cable causes condensation between the sand and the sheeting and this returns moisture to the sand.

I also think that wetting the sand spreads the heat better and creates a nice humidity around the plants meaning the plants don't seem to damp off as much.

As I have mentioned before I think damping off is caused at soil level by the cooler air above soil level meeting the warm compost and this creates extremes in temperature at soil level where damping off generally occurs.

With the reasonably constant humidity around the plant in my case seems to reduce the advent of 'damping off' but not completely as sometimes I am troubled by plants damping off.

I hope this info helps!...Tg

[daveyboi]

Yes indeed it is all fully explained and is a giant version of my poor little cold frame which works well although I tend to use it mainly for growing on tomato plants prior to planting out doors. I do not have a thermostat but have it on a timer to come on at dusk or just before until dawn when it gets warmer out for frost protection later in the season or early on leave it on all the time.

Pictures in my gallery
http://www.allotments4all.co.uk/smf/index.php?action=gallery;su=user;cat=809;u=9619

Thanks again

[Tee Gee]

my poor little cold frame which works well

Don't be despondent Davy....In my book if it works that is all that is required of it.



This is a clearer picture of my set up.

[pumkinlover]

Is the visqueen under or over the sand Teegee?

[Tee Gee]

Is the visqueen under or over the sand Teegee?

It is over the sand, if you look closely at the above picture you can just see the edge of it.

There could well be a layer under it as well but I can't remember after all these years.

I seem to recall the base of the bed is formed of timber slats with 1" thick polystyrene sheeting (cavity insulation boards) over them and then possibly a sheet of visqueen to stop the sand from trickling out.

Then I put in a 2" bed of sand on in and laid out the soil warming cable and thermostat on it then I covered the cable with around another 1" of sand and put on the top sheet of visqueen.

[gray1720]

Oh bu**er! ANother thing I'm so jealous of, I have to build one!

Tee Gee, you are a bad person! Bloomin' good gardener by the looks, but a bad person!
(that's the closest I can see to a green-eyed monster)

Adrian