Your greenhouse has one fundamental purpose: to provide an appropriate environment for growing plants of your choice. Greenhouse construction depends on your size requirement, purpose of the greenhouse, types of plants, available space, site location, architectural style of your house, and of course, your budget. The key to greenhouse construction lies in careful consideration of all the above-mentioned factors as well as meticulous planning of three things, namely, location, type of greenhouse and choice of structural materials.
Location: Site your greenhouse so that your plants get early morning sunlight as far as possible. The direction should complement the light requirements of your plants and keep the greenhouse from being buffeted by cold winter winds.
You could save costs if you build your greenhouse close to sources of heat, water and electricity. Be sure to ensure good drainage as well as easy access.
Deciduous trees can be of advantage if they provide shade in the hot afternoon, but not in early mornings in summers. They are good when you plant to maximize exposure to the winter sun as these trees shed leaves in the fall, and so do not limit light transmission during winters. Based on the same logic, it would not be a good idea to have evergreens or trees that keep their leaves year-round around your greenhouse as they could substantially block sunlight in the winters.
Type of Greenhouse: Your home greenhouse can be a lean-to which shares a common wall with your home. It has the advantage of easy access and lower costs by being located closer to utilities and by sharing a common wall. Your choice of the direction could additionally keep the greenhouse safe from winds. Keep in mind that snow could slide off the main structure on to your greenhouse, so choose a sloping roof for the greenhouse. Be sure to match the greenhouse style with the architecture of your house for aesthetic purpose.
A free-standing structure has the advantage of being larger and admitting more sunlight as these are located away from structures that could cast shadows. This type of greenhouse has a good ratio of cost to available growing space.
Structural materials: A variety of materials such as wood galvanized steel, aluminium or PVC are available as framing materials. Plastic materials are light and are not recommended where a great deal of snow or winds are commonly expected. Glazing materials are to be chosen according to frame compatibility. Acrylic, polycarbonate sheets, plastic films such as polyethylene or poly films, fiberglass and glass each have their own unique set of advantages and disadvantages. Foundations can be made of concrete or lumber, while flooring can be made of gravel, concrete or stone.
As well as the considerations above, greenhouse construction also involves heating, cooling, ventilating and watering systems.