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Gloucestershire, United Kingdom Gb

Propagator problem...
Hello once again. Last time I asked a question on this forum someone called Cliffo caused a bit of a stir. Hope it doesn't happen this time!
Last year I built my own propagator 1700mm x 500mm with a hinged lid covered in polythene. It is placed on the greenhouse bench which is Red Cedar. I followed the advice from Parasene and used 50mm of horticultural sharp sand above and below the soil warming cable. However, when the sand was damp, the weight was far too great for the bench and it nearly collapsed. I am looking for an alternative to sand and propose trying Perlite. I have bought 100L but before I use it in Feb, does anyone envisage any problems?



Only that it must be well watered before you start to empty it out of the bag. the stuff is terribly dusty and unpleasant in its dry state.

20 Dec, 2010


Good advice, thanks! Do you think it will conduct the heat as well as sand?

20 Dec, 2010


As water is a good conductor of heat it should do the job equally well. Perhaps you might consider putting some kind of reinforcement under your propagator because, even though Perlite is a lot lighter than sand, it will still be heavy from the weight of water.

20 Dec, 2010


Did not have time to type much before. but agree with Balcony, even perlite and water is going to be heavy, with pots or trays of cuttings etc on top of it. My propagating frame is based on 3 feet by 2 feet paving slabs on 3 inch fence posts.

20 Dec, 2010


I doubt any 'normal' greenhouse bench will take the weight of either sand or perlite when wet. Follow Owdb's advice and create a good solid sturdy structure.

20 Dec, 2010


Thanks for all the good advice. I will certainly add more support under the bench. However, I am still concerned about the conductivity of perlite. Presumably damp sand is recommended because it works well with water whereas my concern is that perlite is a good insulator and may prevent the warmth from the cable?
I contacted Parasene and they didn't even bother to reply!

21 Dec, 2010

How do I say thanks?

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