Championship Field renovation 2016

removing poa

Fraze Mowing on Championship Field 2016

Dean Pearson

In May of 2016, the Seattle University Athletic Fields team undertook a major project to eradicate Poa Annua (Annual Bluegrass, commonly referred to as Poa) from Championship field.  Annual Bluegrass is an invasive grass with very shallow rooting that results in poor playing conditions for soccer.  It can spread very quickly by seed and loves the cool temperatures and wet climate of the Pacific Northwest.  There are two ways of suppressing or eradicating Poa.  One is by chemical means.  There are various forms of herbicides and growth regulars that will target and suppress Poa, but there are also mechanical means.  At Seattle University, we are committed to a vigorous Integrated Pest Management program avoiding herbicides in all instances and very little chemical application.  With this in mind, we decided to use one of the newest practices in sports turf maintenance, known as Fraze Mowing.  


We contracted Jared Minick, from Growing Innovations to ship his Koro Field Top Maker and operate it.  The machine operates by setting rotating blades to a desired depth, and shooting the debris up a conveyor belt.  We set the machine to negative 4mm depth, which means the blades where grabbing and pulling plant material 4 mm in depth.  Since Poa has much shallower roots than Perennial Ryegrass or Kentucky Bluegrass, the Top Maker is able to pull the plant out of the soil with minimal disruption to the desired grass.  The result was bare patches on the field where Poa was growing, and slightly beat up, but alive Kentucky Blue Grass and Perennial Rye.  In order to get the field back to top shape, we had an extensive over-seeding, aeration, and fertilization program in place post-Fraze Mow.  The results have been fantastic and we will look to using the practice of Fraze mowing in the future.