The commercial products humic acid (Actosol®), humic acid (Actosol®) + NPK and humic acid (Actosol®) + micro-elements (Fe, Mn, Cu) were tested against the root-knot nematode, Meloidogyne incognita, in vitro and in vivo on tomato and compared with the nematicide, Vydate. In vitro, Vydate at 2 ml l–1 water was the best treatment for inhibiting hatch (30.8% inhibition) and was significantly more effective than all other treatments, except Vydate at 4 ml l–1. Humic acid + micro-elements (2 ml l–1 water) was the least effective treatment for inhibiting hatch. Humic acid supplemented with micro-elements was significantly better than other products in reducing the number of surviving juveniles and achieving the highest percentage of nematode inhibition (49.2%), followed by the two concentrations of Vydate, which were not significantly different from one another. In vivo, all treatments significantly reduced the numbers of galls, embedded stages in roots, final population and population build-up (Pf/Pi) in all types of soil as compared to the untreated control. Materials appeared to be more effective at preventing nematode penetration of roots in sandy loam soil than in the other two soil types (sandy and clay). The double application of humic acid + NPK gave the best plant growth (fresh and dry weights) in sandy loam soil. All treatments reduced plant content of NPK in sandy soil except for humic acid + micro-elements and the two doses of Vydate.