Doing a search for heaters and found this.....not what I am looking for but
interesting idea.
Anyone heard of them??

Greenhouse Heating

Greenheat are a company who have produced two new products to heat the
greenhouse, The Greenheat Organic Greenhouse Heater and Fuel.

The heater is fuelled by Greenheat's organic fuel gel made from sugar cane
and they claim produces no smelly toxic waste gases. They state that upon
burning the gel fuel actually emits plant food (carbon dioxide and water
vapour).

The Heater retails at around £60 and the 5 litre fuel refill retails at
£7.99 providing over 65 hours of burn time.

Contact Greenheat, 87 Stokes Croft, Bristol BS1 3RD. Tel: 0117 923 2300
email: web: www.greenheat.co.uk


--
David Hill
Abacus Nurseries
www.abacus-nurseries.co.uk