Roof greening is the practice of creating a green space on rooftops, often involving the installation of a growing medium and plants. A 'roof greening plan' would be a detailed design or blueprint that outlines the specific layout, types of plants, and construction requirements for a successful rooftop garden. This includes considerations for soil depth, irrigation systems, drainage, and structural support to ensure the garden can thrive on the rooftop without causing damage to the building.