PRE and POST herbicides were evaluated for their effects on root growth of Kentucky bluegrass and tall fescue turf. All PRE treatments, bensulide at 14.0 kg ai ha−1, DCPA at 11.8 kg ha−1, dithiopyr at 0.4 kg ha−1, pendimethalin at 1.7 kg ha−1, and prodiamine at 0.6 kg ha−1, inhibited root growth when cores, 10 cm in diam and 2.5 cm deep, of herbicide-treated Kentucky bluegrass were placed into pots of perlite. Only prodiamine inhibited tall fescue rooting. None of the PRE treatments reduced rooting of grasses when 10-cm diam and 16-cm deep cores were sampled from the field. No differences in rooting were observed among any of the POST treatments on either species.