What should be done to the growing media before planting in vegetated roofs?

Moistening the growing media prior to planting is essential for several reasons. When the growing media is adequately moistened, it ensures that the roots of the plants can easily access the water they need for establishment and growth. Dry media can lead to a phenomenon known as hydrophobicity, where the soil repels water, making it difficult for the water to penetrate and reach the plant roots. This can result in poor plant establishment and increased stress for the plants.

Additionally, moist media facilitates better seed-to-soil contact for seeds that may be directly sown, promoting germination and contributing to a more successful growth outcome. It also allows for improved nutrient availability in the media, as water helps dissolve nutrients, making them more accessible to plants. Overall, pre-moistening the growing media establishes a suitable environment for plant survival and growth, which is crucial in the specialized conditions of a vegetated roof.