The hydraulic seeding and mulching industry has come a long way since its original development in the 1950s. The basic elements of the process, however, have remained the same, with a few exceptions. The types and specific characteristics of hydraulic mulch materials, for instance, continue to grow and become more diverse.
Originally, hydraulic mulches were made of cellulose fiber. Then, new wood fiber technologies were proven to provide significant advantages in both mixing and on-the-ground performance. By producing a more fibrous material with the right fiber size distribution, key performance characteristics provided superior results in vegetation establishment and erosion control.
What makes a good hydraulic mulch material? To determine the answer, we need to consider exactly what we are trying to accomplish. It generally is agreed that protection of the seed, providing moisture to the seed and accelerating germination and growth are all keys to success. Another important factor is physical ground coverage. If a house painter uses an inferior paint and slaps it on thin with a low-quality brush, the wall coverage will look poor and the surface will be exposed to wear from environmental effects. Such is the case with hydraulic mulching—the quality characteristics of the fiber and the rate at which it is applied are critical.
The following is a short list of hydraulic mulch characteristics and the benefits derived from using each:
- Quality raw materials. These have no germination or growth inhibitors.
- Long fiber lengths that interlock. This characteristic promotes superior erosion control.
- Varied fiber sizes. Using several sizes facilitates faster moisture absorption.
- Thermally refined fibers. They provide greater moisture retention and physical ground coverage.
This takes us to the price vs. cost game. Again, the paint comparison holds true. If a painter uses the cheaper, thinner paint, it may take twice as much product to cover the same area. Due to the competitive landscape within today’s market, many contractors feel compelled to cut back on materials. In order to ensure success of specified hydraulic mulch projects, one must follow more detailed specifications and inspection requirements.
The industry must make a concerted effort to educate project engineers, architects and specifiers as to the features and benefits of hydraulic mulch material offerings. Today’s hydraulic mulch material product hierarchy includes materials ranging from cellulose fiber to 100% wood fiber. The upper end includes stabilized mulch matrix, bonded fiber matrix, flexible growth medium and extended-term fiber matrices that can last more than 18 months in arid regions.
Resources are available to architects and engineers to help create solid hydraulic seeding and mulching specifications. Some websites include product performance data and application rate charts. New material selection software is available free of charge and allows specifiers to enter site-specific project data and soil results.
If we can educate specifiers, contractors and project owners about the various hydraulic erosion control options that are available to them, we can help ensure project success while “keeping it green.”