Many specialist books have been written on the siting and structure of these useful additions to the garden but our primary concern here is with their appearance. Appearance, however, has to be tempered with practicality, for some of the greenhouse models on the market are too small and contrived in shape to be of much use. The “plantsman” will first decide on the greenhouse that is suitable for his growing needs, considering its appearance second. The determining factors will be the type of crop he wishes to grow and how much time he can spare on the maintenance of the greenhouse.
The siting, as well as the function of the greenhouse, will to an extent determine the type you need. The materials of which it is constructed can be painted or stained softwood, cedar or metal. The shape may be of the ridge type, the lean-to, the hexagonal or many sided, which themselves might be ridged, or it can be dome-shaped.
Greenhouses can now be fully automatic, in watering, ventilation and shading, but such sophistication becomes practicable only when there is a reasonably large area of glass. Most people settle for a greenhouse which they use for over-wintering, and then for seed sowing in spring and the propagation of cuttings for later summer use. Tomatoes and pepper can be grown throughout the summer, but without automatic equipment their watering can become a chore. The smaller the greenhouse the more difficult it is to control the temperature, and therefore the watering.
A frame with underground heating would provide most people with all the glass they really need. The range of frame types is limited. It is reasonably easy to build your own of brick or, less permanently, of timber, with a simple lift-up framed glass top. If frames are not heated with underground wires, they can still be used to harden plants which have been raised from seed.
Both frames and greenhouse will need to be sited where sunshine is plentiful and therefore free from the overhang of trees. You must remember that in winter, snow is liable to build up on a greenhouse roof and must be cleared regularly. Overhanging trees will deposit collected snow with what might be disastrous results.
Frames and greenhouses should be serviced by hard, dry paths, wide enough for a wheelbarrow. Allow plenty for space around them for standing pots and boxes.
Treated as small, efficient working units, frames and greenhouses can make handsome features on their own and need little screening.