Hydroseeding is a spray-on water-based mixture of grass seed, wood fiber and fertilizer. It is often used to grow grass on steep slopes to help prevent soil erosion. The process of hydroseeding involves fiber mulch, fertilizer, water, seed and sometimes lime being mixed together inside a tank, and then applied directly over a prepared ground, using a spray hose. Once the lawn area is thoroughly sprayed, the moist fiber mulch then works to produce a bond with the soil, and also gives the seeds a water-retaining layer to defend them against the sunlight, erosion and wind. Once the seeds start to germinate, and the fiber mulch gradually decompose, providing the soil with nutrients.