Allotment Gardening Advice Help Chat
Growing => Growing in Greenhouses & Polytunnels => Topic started by: Caretaker on January 16, 2014, 12:23
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I made a propagator last year with warming cable and thermostat and this is on the greenhouse bench, I have put sand in to cover the heating cable as advised by the makers 4 bags about 3 inches, it seems a bit heavy, can I use something lighter than sand?
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Grit sand is the stuff you really need to use as it doesn't 'cake' so much when wet. I don't think there is anything else you could use. But I'm looking forward to others suggestions.
Cheers, Tony.
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Just a thought, could perlite be used?
Its nice and light.
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Just a thought, what about the flame retardant polystyrene beads like in bean bags
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I was also thinking of Perlite, this is what I found on Google.
Expanded Perlite Use in Horticulture
In horticultural applications, perlite is used throughout the world as a component of soilless growing mixes where it provides aeration and optimum moisture retention for superior plant growth. For rooting cuttings, 100% perlite is used. Studies have shown that outstanding yields are achieved with perlite hydroponic systems.
Other benefits of horticultural perlite are its neutral pH and the fact that it is sterile and weed-free. In addition, its light weight makes it ideal for use in container growing.
Other horticultural applications for perlite are as a carrier for fertilizer, herbicides and pesticides and for pelletizing seed. Horticultural perlite is as useful to the home gardener as it is to the commercial grower. It is used with equal success in greenhouse growing, landscaping applications and in the home in house plants.
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I made one too, about twenty years ago and still going strong. About 4 ft x 2 ft. Takes 2 x 25Kg bags of sharp sand each year to cover the heating cable. 3 inches of sand is far more than I'd recommend. My cable rests on about 3/4 inch of sand and is covered by the same amount. Cost of sand is less than 4 quid from Wickes. At each season's end the sand gets brushed into the lawn so it's not wasted.
As a matter of fact I just set mine up last weekend for the new season's sowings, starting with onion seed