Hydroseeding (or hydraulic mulch seeding, hydro-mulching, hydraseeding) is a planting process that uses a slurry of seed and mulch. It is often used as an erosion control technique on construction sites, as an alternative to the traditional process of broadcasting or sowing dry seed.
The hydroseeding slurry is transported in a tank, either truck- or trailer-mounted and sprayed over prepared ground. Helicopters have been used to cover larger areas. Aircraft application may also be used on burned wilderness areas after a fire, and in such uses may contain only soil stabilizer to avoid introducing non-native plant species. Hydroseeding is an alternative to the traditional process of broadcasting or sowing dry seed. A study conducted along the lower Colorado River in Arizona, the United States found that hydroseeding could be used to restore riparian vegetation in cleared land.
The slurry often has other ingredients including fertilizer, tackifying agents, fiber mulch, and green dye.
The first commercial hydroseeder was invented in United States in the early 1950s and was used in the United Kingdom in the 1960s.
Advantages of Hydroseeding is if planting a relatively large area, hydroseeding can be completed in a very short period of time. It can be very effective for hillsides and sloping lawns to help with erosion control and quick planting. Hydroseeding will typically cost less than planting with sod, but more than broadcast seeding. Results are often quick with high germination rates producing grass growth in about a week and mowing maintenance beginning around 3 to 4 weeks from the date of application. Fiber mulch accelerates the growing process by maintaining moisture around the seeds thereby increasing the rate of germination.