There are various varieties and many sizes of greenhouse in use today. The glass to ground with a span roofing has high eaves and vertical sides. It is best suited for growing carnations, tomato plants and lots of other plants requiring lots of light. The maximum amount of light is admitted heating the ground thus saving warmth.
Brick based spanned roof green-houses were mainly built in Victorian days to be able to grow pot plants and are totally unacceptable for tomatoes and carnations and so forth. They are still currently available with a wooden base. They usually have some type of staging, the base of which may be used for storage only since nothing will grow here.
The Dutch type span roofing has sloping sides which slope outwards. It is almost always glazed to the ground and for that reason suited to plant which need to have sufficient light. There is certainly one drawback with this particular design being unable to accommodate taller plants close to the glass sides.
The lean-to greenhouse is only recommended now where there isn't a suitable site for a span roof type. For maximum protection from the wind this kind is best built facing southerly. They have an advantage of gaining some heat radiated from your house wall. There are a large number of lean-to houses, most of these tend to be glass to ground while others have timber bases. The Dutch kind lean-to can give a great width and can be fixed against relatively low walls.
The three quarter span green house is just a modified lean-to which allows some north light to penetrate. Fruit trees for instance peaches may be grown or ornamental climbers because these may be trained against the high wall.
To provide the best of both worlds a dual purpose greenhouse can be acquired. These houses are glazed to the ground on one side only, the other side being boarded up to provide winter storage for fuchsias, dahlia tubers as well as other plants.
The real key element to a successful garden greenhouse is to admit the maximum amount of natural light as you possibly can.