This study examines factors determining farmers’ investment in organic farming using a contextualized lab-in-the-field experiment with 220 small household farmers in Northern Vietnam. We focus on the role of network structure, information nudge, and social comparison between farmers using three types of networks: circle, star and complete. Our results suggest that, on average, around 64% of the land is invested in organic farming in the complete network in which each farmer is connected to all of the others, while only about 57% of the land is invested in the circle and star network. Moreover, social comparison (i.e., information about the average investment) performs better in a circle network than in a star network. Finally, information nudges about the socially optimal investment could encourage farmers’ coordination in all three networks, particularly in the complete network with an increase in organic investment up to 76%.