location considerations
Your greenhouse should be located where it gets maximum sunlight. The first choice of location is the south or southeast side of a building or shade trees. Sunlight all day is best, but morning sunlight on the east side is sufficient for plants. Morning sunlight is most desirable because it allows the plant's food production process to begin early; thus growth is maximized. An east side location captures the most November to February sunlight. The next best sites are southwest and west of major structures, where plants receive sunlight later in the day. North of major structures is the least desirable location and is good only for plants that require little light.

Deciduous trees, such as maple and oak, can effectively shade the greenhouse from the intense late afternoon summer sun; however, they should not shade the greenhouse in the morning. Deciduous trees also allow maximum exposure to the winter sun because they shed their leaves in the fall. Evergreen trees that have foliage year round should not be located where they will shade the greenhouse because they will block the less intense winter sun. You should aim to maximize winter sun exposure, particularly if the greenhouse is used all year. Remember that the sun is lower in the southern sky in winter causing long shadows to be cast by buildings and evergreen trees on the greenhouse.

Good drainage is another requirement for the greenhouse site. When necessary, build the greenhouse above the surrounding ground so rainwater and irrigation water will drain away.

Other site considerations include the light requirements of the plants to be grown; locations of sources of heat, water, and electricity; and shelter from winter wind. Access to the greenhouse should be convenient for both people and utilities.

water / irrigation
Consider bringing a water source just inside your grow house (for maximum winter protection), and water your plants with either broad casting misting system hung from the ceiling, or discrete individual plant controlled drip systems.

electrical wiring
For the more avid horticulturist, consider bringing electricity into your greenhouse. But remember, electricity and water (moisture) don't mix, and your greenhouse will bring these two together. But with special consideration and proper wiring to code, this isn't an issue. Lighting must be waterproof, while heaters, exhaust fans, and other electrical items need to be properly grounded and suited for the environment.

ventilation
Balancing humidity and warmth, a well ventilated greenhouse retains enough moisture for healthy growth, with minimum external irrigation, and heat for a happy plant environment. If your green house is too humid, plants will rot. Too hot and too dry, and they will wither.

heaters
These are especially handy for extreme winters or plants requiring moderate temperature control. Heaters can keep the frost at bay and significantly extend a growing season for many plants, particularly those bearing fruit. With proper control in your greenhouse, plants like tomatoes and other above ground vegetables will winter well through the second or third frost cycles of the season. In the winter months there may not be enough light to encourage good produce, unless you are using a grow light.

grow lights
Grow-lights deliver a balanced and broad spectrum of light to encourage virtually any plant to grow, day or night. Installation is generally simple, but water resistant or water proof lighting products are the only way to go.

shelves
These store multiple rows of shorter plants and allow the gardener to prune, water, aerate and fertilize plants without having to bend over as frequently. Taller plants grown from the greenshouse soil may be hindered by lower shelving systems.

work bench
These store plants seeds, tools, and allow the gardener space to prune, water, aerate and fertilize the plants. Not all greenhouses need a workbench, but gardeners who are considering a nursery-style greenhouse can benefit from the extra space.

air-tight storage cabinet
Keeping your reference books and plant care notes handy, in a humid and tropical setting may seem futile, but it is possible to keep your reference and garden books in your greenhouse without having to throw them onto the compost heap. Airtight cabinets (with seals) will do the trick.

shade cloths
For sun sensitive plants in your greenhouse, a shade cloth will allow some sun light to come through, while preventing scorching and burning.