Everyone knows plants grow best in a tepid climate with plenty of water. Plants need sunlight to go through the process of photosynthesis, which is how they produce the energy needed for them to survive. A greenhouse allows sunlight in and keeps the environment comfortable, but how?
The clear glass or plastic on greenhouse ceilings and walls allows sunlight into the structure. The plants absorb the sunlight and convert it to heat. As the heat is expelled it becomes trapped in the greenhouse. The sunlight also helps to warm the trapped air. This is the conversion of solar energy to thermal energy.
When the plants, soil, and air get warm and moist this is called convection. As the plants heat up, they release moisture and create humidity. Humidity also helps the plants to retain water. In freezing temperatures extra heat must be added to keep the temperature at a constant and during warm summer months, ventilation will let excess heat and humidity escape.
