Horticultural glass is 3mm thick easily breakable, and will leave shards and splinters of glass. It is cheaper to replace, but much easier to damage.

Toughened glass is just that..Much harder to break and when it does it breaks in to thousands of little bits...Like a car windscreen...a lot less likely to cut you. More expensive but more durable.

Another option would be plastic, but this lets in less light than glass and inevitably gets scratched and blemished over a relatively short period.

Ok thanks Pimpernel...there's so many options to choose from out there :)

At the end of the day, you only get what you pay for. If you are an avid gardener and will get many hours of pleasure from your greenhouse, then buy the best you can afford. Toughened glass and a rigid aluminium will serve you well. Also what seems enormous at first, will soon be filled once the growing season starts.

Have you got kids around if so keep away from glass I have a young grandson and I replaced my greenhouse glass with 6mm polycarbonate? its cheap and very tough

No kids are teenages so i don't really have to worry too much about that steveg..I was just really wanting to know which is the very best for good results :)

Location is important. In a windy spot you will need a good quality aluminum or wooden greenhouse with toughened glass. In a sheltered spot you could get a plastic/horticultural glass windowed one.

Jan/Feb is the cheapest time to buy greenhouses.

thanks Kildermorie..yes it will be a sheltered posistion and good I have a couple of months to look around :)

Kate, also 'Think big'. I made the mistake of buying a 6' x 8' greenhouse, and very soon found it wasn't large enough.

Also, get electricity into it - you'll probably need a thermostatically controlled fan heater, which also blows cool air in the summer. You might also want a heated propagator in there in the future...so electricity to me is a 'must-have'.

Think like Spritz...Your Green House will generate your garden..I would look in to a second hand larger one..Ebay

Note that polycarbonate and other plastics are more flexible than glass, and have also been known to pop out of the frame in high winds--awkward in a snow storm!

Thanks again to you all..I'm going BIG 27 x 40ft :) jokes!! I'm taking all this on board and going to start looking around.

Check out the prices on 't' net, Kate, if you do buy new. We found a huge difference between sites. Also, your local GC and DIY stores - get quotes from them too.