Greenhouses are structures specifically designed to create and maintain an optimal environment for plant growth. They are often made of transparent materials such as glass or plastic, allowing sunlight to enter and heat the interior. Greenhouses are used by both hobbyists and commercial growers to extend the growing season, protect plants from harsh weather conditions, and control variables such as temperature, humidity, and light exposure. They are commonly used to grow fruits, vegetables, flowers, and other plants in a controlled and protected environment. Greenhouses can range in size from small backyard structures to large commercial facilities.