What occurs in a glass greenhouses so that it becomes warmer inside then outside?

In glass greenhouses, sunlight enters through the transparent glass and warms the interior surfaces, such as plants and soil. These surfaces then emit heat in the form of infrared radiation, which is trapped inside the greenhouse due to the glass, preventing it from escaping. This phenomenon, known as the greenhouse effect, leads to higher temperatures inside the greenhouse compared to the outside environment, creating a warm microclimate that is ideal for plant growth.