A Connecticut highway worker by the name of Maurice Mandell discovered the efficient way to seed while working on the steep embankments of the expressway in the 50’s. By mixing seed and keeping it suspended in water it could be sprayed directly onto the ground surface from tanks. Charles Finn, having previously designed the first straw mulch blower, took this idea and developed it into what is now known as the ‘Hydroseeder.’ This machine consisted of a 1000 gallon mixing tank and towable sprayer, pump and engine, with an internal paddle for a constant agitation of seeding. Since the technique of Hydroseeding was discovered in the 1950’s, it has been referred to as many things and has many common variants such as hydroseed, hydro seeding, spray grass and hydraulic seeding.
Hydroseeding, which differs slightly from hydromulching, is the hydraulic application of a mixture of seed, water, fertiliser and tracking dye sprayed on top of topsoil through a cannon or hose connected to a hydroseeder. It is distinguished from hydromulching by the fact that it doesn’t utilise a cellulosic fibre mulch in the mixture, despite both words often being used synonymously. Hydroseeding mixtures usually contain cover crop seeds of a single origin or a blend of seeds and a fertiliser mix that is based on an initial soil test of the site. The long-term soil-building benefits of a biologically-active soil conditioner such as a soluble humic acid, along with a binding/tackifing product, are commonly added to the mixture. The binder/tackifier essentially acts as a “glue” that holds the seeds to the soil so that they remain in place long enough to germinate without being washed away in a rain event. Hydroseeding solutions are usually utilised where mulch is not needed as the soil is healthy and irrigation is adequate, with binders and tackifiers added to the mixture to reduce the erosive forces of wind and rain on the seeds.
Hydroseeding can revegetate and cover a vast area very quickly, much quicker than direct seeding methods such as broadcast or drill seeding, and represents a far cheaper way to revegetate than rolled turf. It can be used to revegetate areas that are difficult or dangerous to access as well as flat areas, batters and slopes (with the addition of a binder) that are less than 2h:1v, stockpiles and mounds, making the task of providing erosion control for verges and soil stockpiles much easier. Hydroseeding can also cater for sites that require native vegetation, being able to provide custom seed and fertiliser blends to produce as little impact on the environment as possible.