Final answer:
Greenhouses provide a controlled environment where not only is the sunlight input manageable through the use of covers and various light sources, but also the Greenhouse Effect is harnessed to maintain optimal growing temperatures.
Step-by-step explanation:
Greenhouses are indeed controlled environments designed specifically for the optimal growth of plants. Contrary to the belief that sunlights input cannot be controlled in greenhouses, the reality is different. Not only can sunlight be manipulated through the strategic use of covers like blackout shade cloth to lengthen the night for certain plants but also, the exposure to light for long-day plants can be augmented using red light to promote early flowering during winter months.
Moreover, greenhouse management relies on the use of different types of lights such as fluorescent lights, which are rich in blue wavelengths, to encourage leafy growth and are excellent for starting seedlings. On the other hand, incandescent lamps provide red light to promote flowering in some types of plants. Additionally, the application of plant hormones can adjust the timing of fruit ripening, either hastening or delaying the process to meet specific requirements.
In greenhouses, the Greenhouse Effect also plays a significant role by trapping heat within the structure, allowing gardeners to maintain appropriate temperature levels for heat-loving or cold-sensitive plants like tomatoes and peppers. This phenomenon mirrors the natural greenhouse effect where gases in the atmosphere trap solar radiation and re-radiate it as heat, thus warming the environment.