We empirically assess the responsiveness of Senegalese onion producers to significant changes in product market conditions, whereby onions are sold no longer based on volume but on weight and with labeling certifying quality. A village-level randomized information campaign on the upcoming introduction of these market reforms induced significant increase by farmers in the use of quality-enhancing inputs. Delays in the effective introduction of scales enabled us to show positive price returns from these quality- enhancing investments. These results point to the importance of improvements in the functioning of product markets to trigger technology adoption by farmers. Introduction of scales and labels was, however, not sustained as it challenged the market power of wholesale intermediaries. For these reforms to be sustainable, effective market regulation would be necessary.