A process of preparing Arbuscular mycorrhiza (AM) fungi containing substrate for improving root colonization of a host plant is provided. The process includes (a) inoculating 15g 20g of the Arbuscular mycorrhizal (AM) fungi on 1 kg of coir pith fibre, to obtain an AM fungi containing coir pith substrate, (b) sowing seeds of the host plant on the AM fungi containing coir pith substrate, (c) adjusting a pH of the AM fungi containing coir pith substrate to 5.6 to 6.5 and (d) incubating the AM fungi containing coir pith substrate that is sowed with the seeds of the host plant at a room temperature and a moisture that ranges from 30% to 35% for 60-70 days to improve root colonization of the host plant.
