I read a blog from one of our talk radio media blasters ( maybe based in Asia ) a month or two ago that roots may not be so important. We resurfaced our putting green in June and laid L93 turf on the 12th and we had to replace a few strips because of contamination of barnyard grass on the 24th when the photo was taken. HOC 5mm 3 times per week.
https://www.youtube.com/watch?v=SgKy5s3p_Yk Here is youtube since I could not post a picture.
My latest biological granular formulation, BIO-RAIN PLUS was put below the sod at 20 grams per sq meter or 4lbs. per thousand.
Saludos Michael Marbella Golf CC