Mulches for Establishing Grass On Steep Slopes: What Works?.

Construction of buildings and roads often results in cut and fill areas with steep slopes.  These areas are highly susceptible to erosion and in many cases the plans call for grass to be established quickly to prevent this.  In order to foster good grass establishment, a temporary ground cover is applied to protect the seed and young grass from erosion.  The primary types of ground cover used on construction sites are straw, erosion control blankets, and hydromulch, and these can be combined with polyacrylamide (PAM) for potentially greater erosion control.  Over the last 10 years, we have conducted numerous tests of these products on steep (usually 2:1) construction site slopes to evaluate their erosion control and grass establishment effects.  Several key findings are that any ground cover properly applied will greatly reduce erosion, PAM may improve erosion control with ground covers but is not a substitute, and there are no clear advantages of one type of ground cover over another.  The primary factor in controlling the success of grass establishment appears to be weather (rainfall patterns and temperature).  The temperature regime is a function of the time of year when the grass needs to be established, often beyond the control of the site manager, but it may be cost effective to supplement natural rainfall at critical times of grass establishment.