What does this mean?
In simple terms, this means that seed and a growth medium, most commonly being yard compost mixed with bark fines, is blown onto a prepared surface via a blower truck. Unlike hydroseeding, this application goes on dry and provides the establishment of vegetation quicker than hydroseeding. It is effective on difficult slopes 3:1 or greater and where access is limited. The depth of the growth medium varies depending on the application. For example, if you are topdressing on a 5:1 slope a depth of 12.5-25mm is sufficient, while a slope of 1:1 would require a 100mm depth for erosion control. The growth medium protects the soil surface from direct rainfall impact, reduces the velocity of runoff, and fosters the growth of vegetation by conserving moisture and preventing the washing away of seed.