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I have a heated propagator which isn't yet in service this spring as we have moved our greenhouse from the back of the housewhere it had a ready water and electricity supply to the front of teh side garden where it will get full sun and, in theory, give better crops of tomatoes.    i'll use the propagator later on for cuttings and seeds needing bottom heat.

Meanwhile I have tomato and chilli seeds germinating with the help of radiators indoors and other seeds sown in trays which are dispersed on various sunny windo sills.


Years ago in a previous house I had a lovely greenhouse with a big sort of coldframe in it which was full of sand with a cable buried in it. It was great. I sowed all my seeds in trays in it. Now I just have my old dog's (she died) plastic bed which I've filled with damp sand and put a warming cable in it. It's in the greenhouse and I have electric propagators for sowing seeds, but when they are up I put them in the dog bed and cover it with clear plastic when frosts are expected.

Brumbull wrote (see)

Just  watched this Ben and i think there are definate advantages of having one of these especially if your striking cuttings

indeed, should last a while too! very simple to make, and due to the size of mine, helps keep the GH frost free too.


well brum, being a ninja, (well on saving cash! 3 women in the house!) I got my hands on panel heaters.. they are rubbish for heating a room or drying clothes, BUT, they cost pennies to run, typically less than 5 p a day, and that's them on all day. I have two, back to back on a wooden frame I constructed, connected to a thermostatic plug, I am finding just how powerful they are. Currently have a tent of bubblewrap inside my gh, it's a big 'tent' because gh is 10foot by 12. Basically tent is 2/3rds.. before I got the thermostat plug these two were keeping the gh at 18 degrees lol.. So next year I'm going to have bubblewrap up to about 4 foot wrapped around my staging, obviously moved inwards from the walls, but I think most stuff will be fine, quite tempted to see if just them two panels can keep whole gh frost free, if not I could add 2 more, honestly, 20p per 24 hrs, how can u say no? By the way, I do have the thicker safety glass due to my young kids, just incase that makes a difference.

Price for the heated bench is prob pennies a day btw.



Doing it on the cheap here using light bulbs for heat with a glass panel with the seed tray on top. The difference in temperature is quite impressive but the energy use is tiny Like a kilowatt a week. Air temp varies but typically 9 - 13 degrees with the soil temperature about 25 degrees.

A natural alternative can be grass clippings they belt out heat. It seems a bit wasteful to be spending out on heating for plants.



This is indeed what I researched also, the cost isn't really that high at pennies a day, I also liked the fact you can make it any shape or size to suit your needs. Currently, I have sown some birdeye chilli seeds and that's it, I'm not worried about rushing to germinate anything because I can do 8 trays in one go. The thing I wait for is the light intensity, once that's up, then it'll be all systems go. It makes a big difference as you don't end up having seed trays all over the house, and with 2 kids under 5 that doesn't work too well!


Nah, serious bud, if it's in the greenhouse like mine, you need one sunny day and temps are fine. It takes a while from cold otherwise, but the heaters work well providing you get the correct length for the size you need. I have only used some recycled compost bags to line the box, no need for polystyrene, it seems once you get the damp sand up to temp on a decent sized bench, it has no problems maintaining the temps. Just use the propagator kits from wilco etc, just to stick over trays and cell trays. Also saved a few 3 litre pop bottles with the bottom end cut off , make great bell cloches. Next year I'm going to try growing spinach through the winter in drain pipes sat on my bench. Be something to try eh?


well, when I get my shed sorted, I'm going to be able to do soooo sooo much more. Mainly because I'll be able to get at all my stuff.


actually going all out here, maybe we can arrange you and your wife to come around sometime? Not sure on your child/wife arrangements, but can accommodate for an afternoon, maybe a bbq etc.. Seem a top fella, be nice to meet you in real life.


What a friendly place this forum is. It would be lovely if you two could meet and discuss gardening because of the forum. I'm sure many of us have a lot in common.

Bunny ...
Whilst sat on a heated bench would be good

I use a small electric blanket ,i place it in a plastic bag,and place it in propergater that i built, on my bench ,i also have a thermastate connected to it. At my other house my father and i had a40foot by10foot gh.and we built a propergater down one side,we heated it by installing central heating in it ,we laid copper pipes in sand on the base of it,we had a small tank one end also a pump,in the tank we fitted a small imerstion heater element.we connected it all up,we also connected a thermastate to the heater,we found the central heating systerm sucsesfull. 


I'm now getting to grips with mark II propagator, this time its  a bit more complicated having thermostat control and a plate warmer as a heating element.

The Plate warmer comes from aldi  €17.99 and claims to be 60 watts (it might be about half that) its essentially a heating pad wrapped in aluminium foil and with a fabric cover. It claims to be able to warm plates to 65- 70 degrees C after 20 minutes but then its supposed to be used as a stack. I am testing it open and temperature seems much lower.    dimensions are 22cm by 1 metre with a wire loop running up and down just the once.

For temperature control I bought a room thermostat these go for as little as €8 plus vat mine was a little more at €12 total. These are very simple devices you can set the dial to between 5 and 35 degrees C and they open a relay at the set point no power required. This will need to be in close contact with the heat pad to avoid measuring air temperature instead of soil temp. my first version there can be a 15 degree difference between air and soil temperature. I  will have to monitor the system when its all together to ensure i don't cook the roots.  

 The wiring mods will be simple enough i just need to switch the live with the thermostat the relay is strong enough to switch 10 amps of ac. so my little current will be fine. the rcd on the circuit should trip if any water gets where it shouldnt. An extra layer of plastic should ensure the heater element stays dry. it will probably get built into a box Tomorrow.  I have a plc knocking about so if i wanted i could use that for control but i think its not needed at this stage. (a suitable plc can be had from 25 euro up used).  Maplin have a little project board for a temperature probe and relay but its 12volt and about 15 euro. 

 I wouldn't recommend doing this if you are not qualified, if you don't know what you are doing you could manage to kill yourself. It'd probably be easy to adapt this to 12 volt dc which would make it portable and safer.

 It looks like the thermostat is going to be over kill as it has one built in the temperatures climbing but still only about 23 degrees so far

 overnight it reached 28 degrees 5 more tomato plants were born using an average of 27 watts an hour, when on it draws 57 watts. Today I will build a box for it which hopefully will reduce the energy use further (room temp was around 8-10 degrees)

I have just bought a 24 m heat cable and thermostat which i have put on a 5 x 3 foot table.After laying out the kiln sand and wetting it with water i took my plants out of the propagator and covered the table with them. The problem i have now is  keeping the sand damp i thought watering the one patch the rest of the sand would draw it up which it doesn't .Its a task having to lift 100 of it to water anybody manage to get round this prob

I thought of running drip hoses in the sand

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