Greenhouses must, first and foremost, work as greenhouses. That means the orientation must be appropriate, they must get sufficient direct sun, be constructed so that the interior climate can be controlled, and be equipped so that plants, and other organisms, can be successfully grown in them. If, in addition to these technical requirements, the greenhouse can also be designed as an architectural amenity, so much the better. Some schools, unfortunately, have a greenhouse that was planned as an architectural amenity first, without sufficient attention being paid to the technicalities of greenhouse design. Those greenhouses do not work for the science program, the plants die, the science faculty uses the space for storage, and the architectural “amenity” becomes an architectural liability.
Proper ventilation, plus heating, cooling and appropriate humidity controls make a greenhouse work. Providing a tall space, but providing ventilation only in the lower portion, creates a layered environment in which the heat at the top eventually fills up the upper portion and intrudes where plants are growing and kills the plants. Ventilation should be both natural and mechanical with operable vents and fans on thermostats. Evaporative coolers often work well to control both heat and humidity. Operable shades are usually required to deal with changing sun angles and weather conditions.
Heating can be accomplished by a variety of means including gas heaters, electric heaters (very expensive to operate), steam heat off the building’s steam loop, solar heat from a rooftop panel system, and solar heat reradiated from a trombe wall. Solar heat radiation from a trombe wall must be carefully analyzed and designed.
Plants in greenhouses need water, thus a source of hot and cold water should be provided. This could be in the form of a large sink with a faucet to which a hose can be attached, or by means of a hose bib. When watering plants, water hits the floor; thus floor drains are needed. Electrical outlets are also needed and should be on a ground-fault interrupted circuit. Lighting, including “grow” lights should also be provided; grow lights could be hung from chains that would allow vertical adjustment for different plants and different conditions. Grow lights could be on a timer or photocell circuit to come on only when needed.
The location of the greenhouse is almost as important as its functional design. Greenhouses located remote from the classrooms of the teachers that could use them may not be used as frequently. A large Midwestern university plant science building had the greenhouses on the roof as architectural elements that, from the outside, looked like diamonds studded into the top of the tower. Unfortunately these greenhouses were on a separate floor from the teaching spaces for which they were planned and they were seldom used, becoming unsightly storage spaces. On the other hand, when a St. Louis area high school was renovated, a greenhouse was restored immediately adjacent to the ninth grade lab/classroom. This space became both an architectural amenity and a functioning, everyday facet of the instructional program partly because of its location.
Outdoor science spaces are amenities which can become the subject of many different student investigations. As noted above, wetlands on a campus can be a science course in themselves. Walk-in “Plant Window Outdoor Science Compound