Posted: 14/01/2013 at 15:55
Hi Yvonne Parsons2,
First off, better to ask and be a fool for a minute, than not ask and be a fool for life, so don't worry about being a 'newbie' no one's born a 'gardener.'
2 books to recommend - Greenhouse expert by Dr DG hessayon, and RHS Growing under Glass by Kenneth Beckett - Both are extremely good books. I didn't know a thing last year, but have read the books, and re-read them, and am now ordering a greenhouse and know exactly what I want and can achieve.
I've decided to go all out and get the Bio Green jumbo propagator with water trays and capillary matting. It comes with a thermostat, which means you can keep a constant temperature, though it may be worth putting a min-max temp thermometer in there just to check the soil temperature is as required.
If you want to heat a greenhouse (I don't know costs of running as haven't got mine yet) I would suggest buying a thermostat that your heater plugs into, assuming it's electric. This will shut it off once at the desired temperature and switch on when too cold. As I've mentioned, I don't know how much it costs to run a greenhouse, but everyone keeps saying expensive. A thermostat should be a given me thinks.
Going back to propagator, the Bio Green one comes with a polypropylene zip up case, which means heat is contained. This should also keep the price of heating down. It's over a meter long so can grow tons if you get the right trays. As people have said though, don't sow too early, as the light levels will lead to long, spindly plants, with the first true leaves a meter in the air if you're not careful with heat and light levels.