DIY electric propagators

timbim_2

Hi all,

I saw a while ago on gardeners world a feature on making your own electric propagator. I've just got round to thinking about doing it, and have had a look on the gardeners world site, but have drawn a blank on finding any instructions. I've done a few google searches as well, but so far have drawn a blank.

Does anybody know of where I might be able to find some instructions, or have any experience of doing this sort of thing themselves?

Tim

Poppycat

I remember that last year but cant recall how they did it

Poppycat

Here you go. I found it

http://www.bbc.co.uk/gardenersworld/video/toby_30minfix/heated_propagator.shtml

timbim_2

Ah. Many thanks, I was looking at the gardenersworld.co.uk site. That'll be both a nice piece of money saving, and much more suited to our garden!

annie123

I just heat wheat bags in the microwave, works fine with my peppers.

balloo_2

Just a thought Could I use underfloor heating the type that fits under the tiled flooring?? Because I can usually buy that on sale in the DIY stores.

alanobrien

That's a sand bed. You need to use the right cable i.e. capable of working in a damp environment as the sand should be wet for better heat conduction. Ideally you will also need a thermostat to control the temperature and reduce your power bill.

If you want something smaller try looking ar reptile (vivarium) heat mats on ebay. These come in a lot of different sizes are relatively cheap. I use them for seed germination and growing on of tropical plants so they should work well with most things.

Davesnave

I mean no offence to Poppycat, who I meet on another thread, but this is a rather idiotic BBC video about something that will take people a damn sight more than 30 minutes to plan, organise and carry out. They shouldn't feel bad about it if it does. Nonetheless, its a very useful resource, because there is too little out there on this subject.

Take your time when dealing with electric and building things. You could maybe make a few improvements to Toby's design too.

For example, the better you can retain the heat, the less you will spend on electricity, so make it twice as deep, a bit wider/longer and use polystyrene insulation boards on the base and sides to make it more efficient. Also, I'd use really decent plastic for a lining.

When I made one of these, I put a layer of Mypex/Phormisol between the cable and the layer of sand above. The reason for that was because I find it useful to root stuff in the sand as well/instead of in pots buried in the sand. The roots formed would otherwise get around the cable and move it when the plant was removed.

Above my bench, I built a simple framework made from roofing laths and an old double glazed window for the back. The front, top and sides were then covered with polythene; the front roll-upable. During the day, I'd roll up the front and place a loose-fitting cloth over the whole to keep the unit shaded and ventilated. Uncovered, the sand would dry out quite quickly.

I think you could probably use heat mats, such as those made by Hotbox. I have one of those too, but it's 12' 6" long, so I won't be trying it!

My design was adapted from one provided by the cable manufacturer, but I don't seem to be able to find that plan on the t'Interweb.:(

ETA: Just another thing, if you make one of these, especially a large or deep one, remember it will be very heavy. I have a solid angle iron frame now, but earlier models eventually destroyed two heavy duty tables. Greenhouse benching may not be enough!

timbim_2

Thanks for all the advice, one major flaw I spotted in his design was screwing into the length of a board, that's a big no-no, we've got plenty of scraps of wood we can use to reinforce the corners. Putting some insulation between the liner and the frame is a very good idea, and I'll definitely find something to put in there. We've got plenty of spare builders membrane that we're digging along one of our fences, to keep out the roots of next doors trees and bamboo!

The weight issue might be an interesting one, and I'll have a look at how well our greenhouse will take it, we've got a standard wooden bench built into the side of the greenhouse on one side, and with some fairly substantial timber on the other, but I may reinforce that under where we want to put it. I'll have to make a trip down to TP soon anyway, we've got a few timber needs popping up around the place, and we'll need some more sand.

Does anyone have any suggestions where to get the heating cable and thermostat? I've found this and this, but it seems a little expensive.

I'll post back as I get on with this, and may well post an account of the building of this, to help anyone else who comes to work on this sort of thing in the future.

Please go on posting advice and experiences, this could go on to become a good resource.

Many thanks,
Tim

Davesnave

Those prices look about right, judging by what I've seen in my wholesaler's catalogue.

These people have been around for a long time, though they're not cheap either:

http://www.simplycontrol.com/catalogue/soilwarming/default.asp

I know these guys still make the cables, but I don't know if they still sell to the public. Might be worth a call.

Warrick Warming Cables
101 Sedlescombe Road North
St. Leonards-On-Sea
East Sussex
TN37 7EJ

Tel: 01424-442485Business Type: Electrical Goods Warrick Warming Cables