The primary purpose of a greenhouse is to create a controlled environment that enhances plant growth. Greenhouses provide protection from harsh weather conditions such as extreme temperatures, wind, rain, and pests, allowing for year-round cultivation of various plants, including vegetables, flowers, and herbs. The design of greenhouses optimizes sunlight exposure while maintaining appropriate humidity and temperature levels, which can be crucial for plant health. By regulating these factors, growers can extend the growing season, increase yields, and improve the overall quality of their crops, making greenhouses valuable in agriculture and horticulture.