A method is presented for either simultaneous or separate residue analysis of 2,6‐dinitro‐N,N‐dipropyl‐4‐trifluoromethylaniline (trifluralin) and N‐butyl‐N‐ethyl‐2, 6‐dinitro‐4‐trifluoromethylaniline (benfluralin) in turfgrass thatch and soil. Trifluralin and/or benfluralin residues are extracted from thatch and soil with acetohitrile‐water mixture, reextracted and purified with C18solid‐phase extraction (SPE) tubes, and quantified by megabore column gas chromatography with a nitrogen specific detector. Method sensitivity for both compounds is 0.05 mg/kg for thatch and 0.02 mg/kg for soil.