Roots of tomato plants (Solanum lycopersicum) are vulnerable to soil-borne pathogens, including root-knot nematodes. Root-knot nematodes can cause yield losses ranging from 25-100 % in tomato crops. They also increase the vulnerability of tomatoes to infection by other soil-borne pathogens such as Fusarium oxyporum f.sp. lycopersici. Current chemical control methods of root-knot nematode have limitations, necessitating new eco-friendly alternatives, and biological products hold promise. In the present study, we tested if applying biological products can precondition field soil and modulate changes to the microbiome to reduce nematode infestation. Field soil was collected from a tomato field trial site where commercially available biological products (microbial, organic and fish+seaweed) were applied during the 2023/2024 crop season. Moneymaker seedlings were transplanted into free-draining plastic pots filled with 80:20 field soil:river sand in the glasshouse. After 14 days, the seedlings were inoculated with freshly extracted viable eggs (~10000) of Meloidogyne javanica. Roots were scored for galling, eggs were counted from infested roots, and rhizosphere and root samples were sequenced for bacterial communities. Tomato plants grown in preconditioned field soil had 26.3 % (Fish+seaweed), 31.8 % (Microbial) and 24.5 % (Organic) reductions in galling level compared with untreated controls. Roots of plants grown in the control soil and inoculated with M. javanica had significantly higher biomass due to a higher galling level. Metabarcoding 16S analysis detected higher abundances of well-known bacterial antagonists such as Streptomyces and Micromonospora in the roots of plants grown in preconditioned soil, suggesting they may contribute to nematode suppression. These findings indicated that biological products are promising alternatives for managing root-knot nematode infestation and merit further investigation.