This article is an empirical contribution on measuring farmers' ability to innovate, and on the effectiveness of a nudge-type non-monetary incentive on their (stated) intention to adopt an innovation such as the French “Label bas carbone”, a voluntary scheme that certifies carbon credits. We propose an original methodology for measuring farmers' capacity to innovate (“innovativeness”), adapting the scale of Goldsmith and Hofacker (1991) to the specificities of farmers' decisions in a professional setting. Based on an online survey with more than 6,000 responses from French farmers, we validate this scale and evaluate with a randomized experiment included in the questionnaire the net impact of a priming nudge targeting the most innovative farmers. The results indicate that the nudge tested has no significant or detectable impact on the surveyed sample, leading us to discuss the effectiveness of nudges when trying to influence high-stakes decisions.